Food
Chapter IV: Growth/Survival Tables
Analysis and Evaluation of Preventive Control Measures for the Control and Reduction/Elimination of Microbial Hazards on Fresh and Fresh-Cut Produce
Chapter IV
Incidence Tables | Outbreaks Tables | Growth/Survival Tables
Outbreaks Associated with Fresh Produce: Incidence, Growth, and Survival of Pathogens in Fresh and Fresh-Cut Produce
Table G/S-1: Survival and Growth of Pathogenic Bacteria on Raw Melons
| Pathogen | Melon Type | pH | Mode of Inoculation | Storage Conditions | Temperature (°C) | Initial Counts (log10 CFU) | Incubation Time | Final Counts (log10 CFU) | Unit | Comments | Reference |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Campylobacter jejuni | Watermelon, cubes | 3.0 | Spot inoculation, cells suspended in saline. 0.02 ml inoculated per cube. | 24 cm2 cubes with 0.05 ml of lemon juice added per cube. Stored in covered sterile stainless-steel trays. | 25-29 | 2.9 | 6 h | 2 | CFU/cube |
pH 4.8 after 6 h. | Castillo and Escartin 1994 |
| C. jejuni | Watermelon, cubes | 5.5 | Spot inoculation, cells suspended in saline. 0.02 ml inoculated per cube. | 24 cm2 cubes without lemon juice. Stored in covered sterile stainless-steel trays. | 25-29 | 2.7 | 6 h | 2.1 | CFU/cube |
pH 5.5 after 6 h. | Castillo and Escartin 1994 |
| C. jejuni | Watermelon, cubes | 5.5 | Spot inoculation, cells suspended in saline. 0.02 ml inoculated per cube. | 24 cm2 cubes without lemon juice. Stored in sterile stainless-steel trays with cover. | 25-29 | 2.4 | 6 h | 1.6 | CFU/cube |
pH 5.5 after 6 h. | Castillo and Escartin 1994 |
| Escherichia coli O157:H7 (4 strains) |
Cantaloupe, rind surface | NRa | Spot inoculation, cells diluted in 0.1% peptone. | Melons were held in covered plastic boxes with 93 + 5% relative humidity. | 25 5 |
~5.2 ~5.2 |
21 d 8 d |
~7.1 <1.0 |
CFU/cm2 CFU/cm2 |
- | Del Rosario and Beuchat 1995 |
| E. coli O157:H7 (4 strains) | Cantaloupe, cubes | 7.01 | Cell suspension diluted in 0.1% peptone and added to sample. | Cubes placed in sealed stomacher bags and incubated. | 25 5 |
3.0 ~3.1 |
34 h 34 h |
~7.0 ~3.1 |
CFU/g CFU/g |
- | Del Rosario and Beuchat 1995 |
| E. coli O157:H7 (4 strains) | Watermelon, cubes | 5.56 | Cell suspension diluted in 0.1% peptone and added to sample. | Cubes placed in sealed stomacher bags and incubated. | 25 5 |
3.0 3.0 |
34 h 34 h |
~8.7 ~3.0 |
CFU/g CFU/g |
- | Del Rosario and Beuchat 1995 |
| E. coli O157:H7 (4 strains) | Watermelon, rind surface | - | Spot inoculation, cells diluted in 0.1% peptone. | Melons were held in covered plastic boxes with 93 + 5% relative humidity. | 25 5 |
~5.2 ~5.2 |
14 d 14 d |
~6.4 <1.0 |
CFU/cm2 CFU/cm2 |
- | Del Rosario and Beuchat 1995 |
| Salmonella (5 serotypes) | Cantaloupe, cubes | 6.67 | Cell suspension diluted in Butterfield's phosphate buffer, added to sample. | Cubes placed in open stomacher bags and incubated aerobically. | 23 5 |
2.0 2.0 |
24 h 24 h |
~7.2 ~1.6 |
CFU/g CFU/g |
- | Golden and others 1993 |
| Salmonella (5 serotypes) | Honeydew, cubes | 5.95 | Cell suspension diluted in Butterfield's phosphate buffer, added to sample. | Cubes placed in open stomacher bags and incubated aerobically. | 23 5 |
2.0 2.0 |
24 h 24 h |
~8.0 ~1.8 |
CFU/g CFU/g |
- | Golden and others 1993 |
| Salmonella (5 serotypes) | Watermelon, cubes | 5.90 | Cell suspension diluted in Butterfield's phosphate buffer, added to sample. | Cubes placed in open stomacher bags and incubated aerobically. | 23 5 |
2.0 2.0 |
24 h 24 h |
8.6 ~1.9 |
CFU/g CFU/g |
- | Golden and others 1993 |
| Shigella flexneri | Watermelon, cubes | NR | Spot inoculation, cells suspended in saline. 1 drop (Pasteur pipette) inoculated per cube. | 12 cm2 cubes, inoculated and stored in sterile covered glass trays. | 22-26 | 2.8 | 6 h | 4.5 | CFU/cm2 | - | Fernandez Escartin and others 1989 |
| S. sonnei |
Watermelon, whole | NR | 30 ml of inoculum was injected into the whole watermelon through the stem scar. | 30 ml of inoculum was injected and incubated. | 30 22 |
2.0 2.0 |
2 d 4 d |
~9.0 ~9.0 |
CFU/g CFU/g | Inoculated with > 102 CFU/g. Melon rotten within 1-2 days at 30°C and 2-3 days at 22°C. | Fredlund and others 1987 |
| a Not reported | |||||||||||
Table G/S-2: Survival and Growth of Pathogenic Bacteria on Raw Fruit Other than Melons
| Pathogen | Fruit Type | pH | Mode of Inoculation | Storage Conditions | Temperature (°C) | Initial Counts (log10 CFU) | Incubation Time | Final Counts (log10 CFU) | Unit | Comments | Reference |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Campylobacter jejuni | Papaya, cubes | 3.0 | Spot inoculation, cells suspended in saline. 0.02 ml inoculated per cube. | 24 cm2 cubes with 0.05 ml of lemon juice added. Stored in sterile stainless-steel trays with cover. | 25-29 | 3.3 | 6 h | <1.0 | CFU/cube |
pH 3.6 after 6 h. | Castillo and Escartin 1994 |
| C. jejuni | Papaya, cubes | 5.0 | Spot inoculation, cells suspended in saline. 0.02 ml inoculated per cube. | 24 cm2 cubes without lemon juice. Stored in sterile stainless-steel trays with cover. | 25-29 | 2.8 | 6 h | 1.7 | CFU/cube | pH 5.0 after 6 h. | Castillo and Escartin 1994 |
| Escherichia coli O157:H7 | Apple (Golden delicious, fresh cut tissue) | NRa | Spot inoculation, 25 µl inoculated per wound. Inoculum suspended in 0.85% saline. | Apples were wounded (one wound per fruit) aseptically by removing a cyclinder of tissue 3 mm in diameter by 3 mm deep. Stored in plastic boxes on fruit pack trays. | 24 | 2.0 4.0 6.0 |
48 h 48 h 48 h |
~5.5 ~6.0 ~6.5 |
CFU per wound | - | Janisiewicz and others 1999 |
| E. coli O157:H7 (2 strains) | Apples (Red delicious, ground) | 4.10 | Cell suspension in tryptone soy broth, inoculated into sample. | Ground apples were stored in a plastic stomacher bag. | 4 10 25 |
~7.5 | 18 d 12 d 5 d |
~6.8 ~5.8 ~8.5 |
CFU/ml CFU/ml CFU/ml | Final pH 5.11. At 25oC no growth within 24 h. | Fisher and Golden 1998 |
| E. coli O157:H7 (2 strains) | Apple (Golden delicious, ground) | 3.84 | Cell suspension in tryptone soy broth, inoculated into sample. | Ground apples were stored in a plastic stomacher bag. | 4 10 25 |
~7.5 | 18 d 12 d 5 d |
~7.2 ~6.8 ~8.2 |
CFU/ml CFU/ml CFU/ml | Final pH 4.95. At 25oC no growth within 24 h. | Fisher and Golden 1998 |
| E. coli O157:H7 (2 strains) | Apples (Rome, ground) | 3.70 | Cell suspension in tryptone soy broth, inoculated into sample. | Ground apples were stored in a plastic stomacher bag. | 4 10 25 |
~7.5 | 18 d 12 d 5 d |
~6.8 ~7.0 ~7.5 |
CFU/ml CFU/ml CFU/ml | Final pH 3.91. At 25oC no growth within 24 h. Slight growth at 48 h followed by decline. | Fisher and Golden 1998 |
| E. coli O157:H7 (2 strains) |
Apples (Winesap, ground) | 3.47 | Cell suspension in tryptone soy broth, inoculated into sample. | Ground apples were stored in a plastic stomacher bag. | 4 10 25 |
~7.5 | 18 d 12 d 5 d |
~7.0 ~7.0 ~7.0 |
CFU/ml CFU/ml CFU/ml | Final pH 4.03. | Fisher and Golden 1998 |
| E. coli O157:H7 | Apple (5 cultivars, whole) |
3.5-4.9 | Infected with 0.1 ml of saline suspension of cells, then wholes were sealed with tape. | Stored in plastic tub at room temperature. | 20-25 | 5.0-5.2 | 2 d | 4.8 - 8.3 | CFU/apple | Survival and growth depended on cultivars and days post harvest. dropped fruit did not differ from tree-picked fruit in promoting growth. | Dingman 2000 |
| E. coli O157:H7 (2 strains) | Orange (Hamlin, peeled) | 6.0-6.5 | Spot inoculation, 20 µl inoculated and spread over 1/8 of total suface area. Inoculum suspended in Butterfield's phosphate buffer. | Inoculated fruit were individually packed in perforated plastic containers. | 4 8 24 |
3.5 | 14 d 14 d 1 d |
~3.2 ~2.5 ~7.5 |
CFU/g CFU/g CFU/g | pH of surface 6.0-6.5. Juice pH 3.8. | Pao and others 1998 |
| Listeria monocytogenes (2 strains) | Orange, (Hamlin, peeled) | 6.0-6.5 | Spot inoculation, 20 µl inoculated and spread over 1/8 of total suface area. Inoculum suspended in Butterfield's phosphate buffer. | Inoculated fruit were individually packed in perforated plastic containers. | 4 8 24 |
3.9 | 14 d 14 d 1 d |
~4.0 ~3.3 ~5.5 |
CFU/g CFU/g CFU/g | - | Pao and others 1998 |
| Staphylococcus aureus (2 strains) |
Orange, (Hamlin, peeled) | 6.0-6.5 | Spot inoculation, 20 µl inoculated and spread over 1/8 of total suface area. Inoculum suspended in Butterfield's phosphate buffer. | Inoculated fruit were individually packed in perforated plastic containers. | 4 8 24 |
~2.8 | 14 d 14 d 1 d |
~2.0 ~2.0 ~3.5 |
CFU/g CFU/g CFU/g | - | Pao and others 1998 |
| Salmonella Chester | Apple (Golden delicious, disks) | 4.1 | Dip inoculation, 30 s. Cells suspended in phosphate-buffered saline (pH 7.2). | NR | 8 | ~ 5.5 | 66 h | ~ 5.3 | CFU/disk | Acidity did not markedly affect viability | Liao and Sapers 2000 |
| S. Chester | Apple (Golden delicious, disks) | 4.1 | Dip inoculation, 30 s. Cells suspended in phosphate-buffered saline (pH 7.2). | NR | 20 | ~ 5.5 | 66 h | ~ 10.4 | CFU/disk | Increased to ca. 10.2 log10 CFU/disk within 18 h | Liao and Sapers 2000 |
| S. Typhi | Papaya, cubes | 5.69 | Spot inoculation, cells suspended in saline. 1 drop (Pasteur pipette) inoculated per cube. | 12 cm2 cubes, inoculated, and stored in covered glass trays. | 25-27 | 2.9 | 6 h | 4.3 | CFU/cube | - | Fernandez Escartin and others 1989 |
| S. Typhi | Papaya, cubes | 3.59 | Spot inoculation, cells suspended in saline. 1 drop (Pasteur pipette) inoculated per cube. | 12 cm2 cubes, 0.05 ml lemon juice added, inoculated, and stored in covered glass trays. | 25-27 | 3.0 | 6 h | 3.8 | CFU/cube | - | Fernandez Escartin and others 1989 |
| Salmonella (2 serotypes) | Orange, (Hamlin, peeled) | 6.0-6.5 | Spot inoculation, 20 µl inoculated and spread over 1/8 of total suface area. Inoculum suspended in Butterfield's phosphate buffer. | Inoculated fruit were individually packed in perforated plastic containers. | 4 8 24 |
4.4 | 14 d 14 d 1 d |
~3.5 ~2.5 ~7.6 |
CFU/g CFU/g CFU/g | - | Pao and others 1998 |
| Shigella (3 species) | Papaya, cubes | 5.69 | Spot inoculation, cells suspended in saline. 1 drop (Pasteur pipette) inoculated per cube. | 12 cm2 cubes, inoculated and stored in covered glass trays. | 25-27 | 2.0-2.4 | 6 h | 3.8-4.2 | CFU/cube | S. sonnei, S. flexneri, S. dysenteriae |
Fernandez Escartin and others 1989 |
| a Not reported | |||||||||||
Table G/S-3: Survival and Growth of Pathogenic Bacteria on Raw Tomatoes
| Pathogen | Produce Type | pH | Method of Inoculation | Storage Conditions | Temperature (°C) | Initial Counts (log10 CFU) | Incubation Time | Final Counts (log10 CFU) | Unit | Comments | Reference |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Listeria monocytogenes (2 strains) | Tomato (chopped) | 4.1 | Cells suspended in 0.1 M phosphate buffer, 10 ml mixed in 1000 g of tomatoes. | Stored in sealed bags with 3% O2 and 97% N2 or ambient air. Tomatoes either unwashed or washed in 210-280 ppm chlorine prior to chopping. | 10 | 4.5-4.8 | 10 d | ~3.5-4.2 | CFU/g | Subjectively judged to be inedible after 10 days due to deterioration. | Beuchat and Brackett 1991 |
| L. monocytogenes (2 strains) | Tomato (chopped) | 4.1 | Cell suspension in 0.1 M phosphate buffer, 10 ml mixed in 1000 g of tomatoes. | Stored in sealed bags with 3% O2 and 97% N2 or ambient air. Tomatoes either unwashed or washed in 210-280 ppm chlorine prior to chopping. | 21 | 5 | 8 d | 1.0-3.5 | CFU/g | Survival slightly better in chlorine treated samples. | Beuchat and Brackett 1991 |
| L. monocytogenes (2 strains) | Tomato (whole, cherry) | Nra | Dip inoculation, inoculum suspended in 0.1 M phosphate buffer. | Stored in sealed bags with 3% O2 and 97% N2 or ambient air. Tomatoes either not washed or washed in 210-280 ppm chlorine. | 10 | 3.5-3.7 | 20 d | 3.5-5.0 | CFU/g | Significant growth observed only for Scott A inoculated onto chlorine treated tomatoes stored in air. Little difference between strains, tomato treatments, or storage conditions. | Beuchat and Brackett 1991 |
| L. monocytogenes (2 strains) | Tomato (whole, cherry) | NR | Dip inoculation, inoculum suspended in 0.1 M phosphate buffer. | Stored in sealed bags with 3% O2 and 97% N2 or ambient air. Tomatoes either not washed or washed in 210-280 ppm chlorine. | 21 | 3.4-3.6 | 2-8 d | 4.8-5.5 | CFU/g | Significant growth observed only for Scott A inoculated onto chlorine treated tomatoes stored in air. Little difference between strains, tomato treatments, or storage conditions. | Beuchat and Brackett 1991 |
| Salmonella Baildon | Tomato (diced) | 4.50-4.52 | Cells suspended in deionized water; 30 ml mixed with 2270 g of tomatoes. | Tomatoes (450 g) were sealed in plastic bags. Stored for up to 12 d. | 4 | 0.4 | 12 d | <1.0 | CFU/g | Not detected in 6 enriched 25-g samples analyzed each day (0, 2, 5, 8, 12 d). | Weissinger and others 2000 |
| S. Baildon | Tomato (diced) | 4.50-4.52 | Cells suspended in deionized water; 30 ml mixed with 2270 g of tomatoes. | Tomatoes (450 g) were sealed in plastic bags. Stored for up to 12 d. | 4 | 3.4 | 12 d | 1.8 | CFU/g | Counts were reduced by 0.40, 0.67. and 0.75 log10 CFU/g after 2, 5, and 8 d, respectively. | Weissinger and others 2000 |
| S. Baildon | Tomato (diced) | 4.39-4.41 | Cell suspended in deionized water; 20 ml mixed with 600 g of tomatoes. | Tomatoes (100 g) were sealed in plastic bags. Stored for up to 72 h. | 21 | 0.79 | 72 h | 8.1 | CFU/g | Counts were 5.32 and 7.60 log10 CFU/g after 24 and 48 h, respectively. | Weissinger and others 2000 |
| S. Baildon | Tomato (diced) | 4.39-4.41 | Cells suspended in deionized water; 20 ml mixed with 600 g of tomatoes. | Tomatoes (100 g) were sealed in plastic bags. Stored for up to 72 h. | 30 | 0.79 | 72 h | 7.94 | CFU/g | Counts were 7.30 and 7.90 log10 CFU/g after 24 and 48 h, respectively. | Weissinger and others 2000 |
| S. Montevideo | Tomato (cut slices) | 4.31-4.52 | Spot inoculation, inoculum suspended in distilled water. 25 µl inoculated onto each slice. | Tomato sliced into quarters. | 25 | 3.4 4.4 7.4 |
12 h 12 h 12 h |
~7.5 ~8.0 ~9.5 |
CFU/slice | - | Wei and others 1995 |
| S. Montevideo | Tomato (mature green, wounded) | 4.33-4.52 | Spot inoculation, inoculum suspended in distilled water. 25 µl inoculated onto each wounded area. | Tomatoes were punctured to a depth of 1-mm and 0.6-cm in diameter in eight separate areas. | 25 | 3.0 4.0 7.0 |
24 h | ~4.8 ~5.5 ~7.0 |
CFU per wounded area | - | Wei and others 1995 |
| S. Montevideo | Tomato (ripe, chopped) | 4.1 | Cell suspension in 0.05 M potassium phosphate buffer. 1ml inoculated into 50 g sample. | 1-cm cubes. Stored in stomacher bags. | 5 20 30 |
4.4 | 96 h 22 h 22 h |
~4.2 ~6.0 ~7.0 |
CFU/g CFU/g CFU/g |
Tomatoes inedible after 22 h at 20 or 30°C and after 96 h at 5°C. | Zhuang and others 1995 |
| S. Montevideo | Tomato (stem scar) | NR | Spot inoculation, inoculum suspended in distilled water. 25 µl inoculated onto stem scar. | - | 20 25 |
8.0 8.0 |
7 d 7 d |
6.5 5.8 |
CFU/stem scar | - | Wei and others 1995 |
| S. Montevideo | Tomato (stem scar) | NR | Spot inoculation, inoculum suspended in TSB. 25 µl inoculated onto stem scar. | - | 20 25 |
7.2 7.2 |
7 d 7 d |
4.6 6.3 |
CFU/stem scar | - | Wei and others 1995 |
| S. Montevideo | Tomato (whole, mature green) | NR | Dip inoculation, inoculum suspended in 0.1 M phosphate buffer. | Stored individually in open plastic bags with relative humidity between 45-60%. | 10 20 30 |
~1.4 | 1-18 d 7 d 2 d |
~ 2.2 ~4.0 ~5.0 |
CFU/cm2 | Populations declined at 20 and 30°C after day 7. | Zhuang and others 1995 |
| S. Montevideo | Tomato, skin | NR | Spot inoculation, cells suspended in distilled water. Sterile filter discs submerged in inoculum and placed on tomatoes. | Filter discs were dried at room temperature for 2 h and removed from tomatoes. Tomatoes were stored at 83% (20°C) or 72% (25°C) relative humidity. | 20 25 |
5.8 5.8 |
5 d 3 d |
<1 <1 |
CFU/area inoculated | - | Wei and others 1995 |
| S. Montevideo | Tomato, skin | NR | Spot inoculation, cells suspended in TSB. Sterile filter discs submerged in inoculum and placed on tomatoes. | Filter discs were dried at room temperature for 2 h and removed from tomatoes. Tomatoes were stored at 83% (20°C) or 72% (25°C) relative humidity. | 20 25 |
5.5 5.5 |
7 d 7 d |
2.6 4.1 |
CFU/area inoculated | - | Wei and others 1995 |
| Salmonella (3 serotypes) |
Tomato (cut, small pieces) | 4.0-4.40 | Cell suspension in saline, 0.1 ml inoculated into 20 g of sample. | Inoculated samples sealed in polyethylene plastic bags. | 22 30 |
1.1 | 24 h | 6.3-6.9 7.2-8.4 |
CFU/g CFU/g |
Final pH 3.90-4.36. S. Enteriditis, S. Infantis, and S. Typhimurium. |
Asplund and Nurmi 1991 |
| aNot reported | |||||||||||
Table G/S-4: Survival and Growth of Pathogenic Bacteria on Raw Vegetables Other than Tomatoes, Sprouts, Lettuce, and Salads
| Pathogen | Produce Type | pH | Mode of Inoculation | Storage Conditions | Temperature (°C) | Initial Counts (log10 CFU) | Incubation Time | Final Counts (log10 CFU) | Unit | Comments | Reference |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Aeromonas hydrophila (2 strains) |
Asparagus | NRa | Dip inoculation, 1 min. Cells suspended in 0.1M potassium phosphate buffer. | Samples stored in 6% CO2, 79% N2, and 15% O2 in glass jars. | 15 4 |
4.5 4.5 |
4 d 14 d |
~8.0 ~ 7.5 |
CFU/g CFU/g | Asparagus first became unacceptable for consumption on day 6 (15°C) or day 21 (4°C). | Berrang and others 1989a |
| A. hydrophila (2 strains) |
Asparagus | NR | Dip inoculation, 1 min. Cells suspended in 0.1M potassium phosphate buffer. | Samples stored in ambient air in glass jars. | 15 4 |
4.5 4.5 |
4 d 21 d |
~8.0 ~ 7.5 |
CFU/g CFU/g | Asparagus first became unacceptable for consumption on day 4 (15°C) or day 15 (4°C). | Berrang and others 1989a |
| A. hydrophila (2 strains) |
Broccoli | NR | Dip inoculation, 1 min. Cells suspended in 0.1M potassium phosphate buffer. | Samples stored in 10% CO2, 79% N2, and 11% O2 in glass jars. | 15 4 |
5.1 4.0 |
4 d 14 d |
~8.2 ~6.0 |
CFU/g CFU/g | Broccoli first became unacceptable for consumption on day 10 (15°C) or day 21 (4°C). | Berrang and others 1989a |
| A. hydrophila (2 strains) |
Broccoli | NR | Dip inoculation, 1 min. Cells suspended in 0.1M potassium phosphate buffer. | Samples stored in ambient air in glass jars. | 15 4 |
5.1 4.0 |
4 d 14 d |
~8.2 ~6.0 |
CFU/g CFU/g | Broccoli first became unacceptable for consumption on day 6 (15°C) or day 21 (4°C). | Berrang and others 1989a |
| A. hydrophila (2 strains) |
Cauliflower | NR | Dip inoculation, 1 min. Cells suspended in 0.1M potassium phosphate buffer. | Samples stored in ambient air in glass jars. | 15 4 |
4.0 3.5 |
4 d 14 d |
~8.5 ~ 5.9 |
CFU/g CFU/g | Cauliflower first became unacceptable for consumption on day 6 (15°C) or day 21 (4°C). | Berrang and others 1989a |
| A. hydrophila (2 strains) |
Cauliflower | NR | Dip inoculation, 1 min. Cells suspended in 0.1M potassium phosphate buffer. | Samples stored in 3% CO2, 79% N2, and 18% O2 in glass jars. | 15 4 |
4.0 3.5 |
4 d 14 d |
~8.5 ~6.0 |
CFU/g CFU/g | Cauliflower first became unacceptable for consumption on day 8 (15°C) or day 21 (4°C). | Berrang and others 1989a |
| A. hydrophila (1 strain) | Endive (chicory) | NR | Cell suspension added to samples. | Stored in moderate vacuum packaging containers under moderate vacuum. | 6.5 | 3.2 | 3-7 d | ~7.0 | CFU/g | - | Aytac and Gorris1994 |
| A. hydrophila (1 strain) | Endive (chicory) | NR | Cell suspension added to samples. | Stored in moderate vacuum packaging container in ambient air. | 6.5 | 3.2 | 3 d | 6.5 | CFU/g | Populations declined to Log 1.0 CFU/g by day 7. | Aytac and Gorris1994 |
| A. hydrophila | Vegetable salads (mixed vegetable) | 6.0 | Cell suspension, injected through a silicone septum. Cells suspended in brain heart infusion broth. | Samples sealed and stored in polypropylene plastic film. | 4 15 |
3.0 3.0 |
9 d 24 h |
~3.5 ~7.9 |
CFU/g | Population at 15°C steadily declined from 24 h to 6 d. | Garcia-Gimeno and others 1996 |
| Clostridium botulinum (10 strains) | Broccoli | 6.9 | Spot inoculation, spores prepared in broth, heat shocked, and diluted in distilled water. | Samples loosely packaged and stored in sealed polyethylene bags. | 21 | 2.0 | 3 d |
NR | spores/g | 6/6 samples toxic. Spoilage observed. | Larson and others 1997 |
| C. botulinum (10 strains) | Broccoli | 6.9 | Spot inoculation, spores prepared in broth, heat shocked, and diluted in distilled water. | Samples loosely packaged and stored in sealed polyethylene bags. | 12 | 2.0 | 9 d | NR | spores/g | 3/6 samples toxic. Gross spoilage observed. | Larson and others 1997 |
| C. botulinum (10 strains) | Broccoli | 6.9 | Spot inoculation, spores prepared in broth, heat shocked, and diluted in distilled water. | Samples loosely packaged and stored in sealed polyethylene bags. | 4 | 2.0 | 30 d | NR | spores/g | 0/6 samples toxic. Gross spoilage observed. | Larson and others 1997 |
| C. botulinum nonproteolytic (8 strains) |
Butternut squash | NR | Spore suspension (2.5 ml) added to 500 g sample. | 1-inch cubes, inoculated and sealed in a polystyrene tray. | 10 5 |
3.0 3.0 |
7 d 21 d |
NR | spores/g | Toxin detected at 7 d (10°C) or 21 d (5°C). No change in appearance. Final pH 6.4 (5°C), 6.7 (10°C). | Austin and others 1998 |
| C. botulinum proteolytic (10 strains) |
Butternut squash | NR | Spore suspension (2.5 ml) added to 500 g sample. | 1-inch cubes, inoculated and sealed in a polystyrene tray. | 15 25 |
2.0 2.0 |
14 d 3 d |
NR | spores/g | Toxin detected at 14 d (15°C) or 3 d (25°C). 15°C samples dry and moldy. Swelling of packaged observed in 25°C samples. Final pH 6.5 (15°C), 6.2 (25°C). | Austin and others 1998 |
| C. botulinum (12 strains) |
Cabbage (shredded) | NR | Spore suspension (1 ml), heat shocked, sprayed onto sample. Spores were suspended in gel-phosphate buffer. | Samples were sealed in 3-qt pouches and stored vented or not vented. Vented bags were placed with space between samples so that air could circulate. | 4.4 12.7 21 |
2.1 2.1 2.1 |
28 d 28 d 28 d |
2.2 2.0 NDb |
MPN spores/g | No toxin detected in samples stored at 4.4°C or 12.7°C. Toxin detected in non-vented samples stored at 21°C after 7 d. Samples were judge to be inedible prior to toxin detection. | Petran and others 1995 |
| C. botulinum (10 strains, 5 type A and 5 type B) |
Cabbage (shredded) | 6.2 | Spore suspended in water, 1 ml heat shocked suspension added to sample. | Stored in ethylene vinyl alcohol bags. Sealed in MAP of 70% CO2 and 30% N2. | 22-25 | 0.8-1.8 | 6 d | NR | spores/g | No toxin detected. | Solomon and others 1990 |
| C. botulinum (10 strains, 5 type A and 5 type B) |
Cabbage (shredded) | 6.2 | Spore suspended in water, 1 ml heat shocked suspension added to sample. | Stored in ethylene vinyl alcohol bags. Sealed in MAP of 70% CO2 and 30% N2. | 22-25 | 2-2.3 | 4 d | NR | spores/g | 5/6 bags toxic. Cabbage acceptable. Only type A grew and produced toxin. | Solomon and others 1990 |
| C. botulinum (10 strains, 5 type A and 5 type B) |
Cabbage (shredded) | 6.2 | Spore suspended in water, 1 ml heat shocked suspension added to sample. | Stored in ethylene vinyl alcohol bags. Sealed in MAP of 70% CO2 and 30% N2. | 22-25 | 2.9 | 4 d | NR | spores/g | 2/2 bags toxic. Cabbage acceptable. Only type A grew and produced toxin. | Solomon and others 1990 |
| C. botulinum (5 strains, type A) | Cabbage (shredded) | 6.2 | Spore suspended in water, 1 ml heat shocked suspension added to sample. | Stored in ethylene vinyl alcohol bags. Sealed in MAP of 70% CO2 and 30% N2. | 22-25 | 1.6-2.1 | 6 d | NR | spores/g | No toxin detected. | Solomon and others 1990 |
| C. botulinum (5 strains, type A) | Cabbage (shredded) | 6.2 | Spore suspended in water, 1 ml heat shocked suspension added to sample. | Stored in ethylene vinyl alcohol bags. Sealed in MAP of 70% CO2 and 30% N2. | 22-25 | 2.5-3.0 | 4 d 5 d 6 d |
NR | spores/g | 5/10 bags toxic at 4 d, 8/10 bags toxic at 5 d, and 9/10 bags toxic at 6 d. Cabbage acceptable. | Solomon and others 1990 |
| C. botulinum (10 strains) | Cabbage (shredded) | 6.4 | Spot inoculation, spores prepared in broth, heat shocked, and diluted in distilled water. | Samples stored in polyethylene bags and vacuum sealed. | 4 12 21 |
2.0 | 37 8 4 |
NR | spores/g | 0/6 samples were toxic at end of storage for all three temperatures. Gross spoilage was observed. | Larson and others 1997 |
| C. botulinum (10 strains) | Carrot (sliced) | 6.3 | Spot inoculation, spores prepared in broth, heat shocked, and diluted in distilled water. | Samples stored in polyethylene bags and vacuum sealed. | 4 12 21 |
2.0 | 78 d 14 d 4 d |
NR | spores/g | 0/6 samples were toxic at end of storage for all three temperatures. Gross spoilage was observed. | Larson and others 1997 |
| C. botulinum nonproteolytic (8 strains) |
Coleslaw | NR | Spore suspension (1 ml) injected through gas-tight septum. | Samples in original package. | 5 10 |
3.0 | 21 d | NR | spores/g | No toxin detected after 21 d. No change in appearance. | Austin and others 1998 |
| C. botulinum proteolytic (10 strains) |
Coleslaw | NR | Spore suspension (1 ml) injected through gas-tight septum. | Samples in original package. | 15 25 |
2.0 | 21 d | NR | spores/g | No toxin detected after 21 d. No change in appearance. | Austin and others 1998 |
| C. botulinum (10 strains) |
Green beans | 6.3 | Spot inoculation, spores prepared in broth, heat shocked, and diluted in distilled water. | Samples loosely packaged and stored in sealed polyethylene bags. | 4 12 21 |
2.0 | 35 9 7 |
NR | spores/g | 0/6 samples toxic at end of storage for all three temperatures. Gross spoilage observed. | Larson and others 1997 |
| C. botulinum proteolytic (10 strains) |
Mushroom (enoki) | NR | Spores suspended in trypticase peptone glucose yeast extract, 0.1ml inoculated per package. | Stored under anaerobic conditions in sealed bags. | 6 15 15 27 |
3.0 | 21 d 7 d 14 d 2 d |
No toxin No toxin Toxin Toxin |
spores/ package | Spoilage evident when toxin detected. | Malizio and Johnson 1991 |
| C. botulinum proteolytic (10 strains) |
Mushroom (enoki) | NR | Spores suspended in trypticase peptone glucose yeast extract, 0.1ml inoculated per package. | Stored under anaerobic conditions in sealed bags. | 15 27 27 |
2.0 | 14 d 2 d 4 d |
Toxin No toxin Toxin |
spores/ package | Spoilage evident when toxin detected. | Malizio and Johnson 1991 |
| C. botulinum proteolytic (10 strains) |
Mushroom (enoki) | NR | Spores suspended in trypticase peptone glucose yeast extract, 0.1ml inoculated per package. | Stored under anaerobic conditions in sealed bags. | 15 21 27 27 |
1.0 | 14 d 21 d 2 d 4 d |
No toxin Toxin No toxin Toxin |
spores/ package | Spoilage evident when toxin detected. | Malizio and Johnson 1991 |
| C. botulinum proteolytic (10 strains) |
Onion | NR | Spore suspension (2.5 ml) added to 500 g sample. | 5-mm slices, inoculated and sealed in polystyrene trays. | 25 | 3.0 | 6 d | - | spores/g | Toxin detected at 6 d. Swelling of package observed but no change in appearance of onions. | Austin and others 1998 |
| C. botulinum nonproteolytic (8 strains) |
Rutabaga | NR | Spore suspension (2.5 ml) added to 500 g sample. | 1-inch cubes, inoculated and sealed in polystyrene tray. | 5 10 |
3.0 3.0 |
21 d | NR | spores/g | No toxin detected after 21 d. No change in appearance. | Austin and others 1998 |
| C. botulinum proteolytic (10 strains) |
Rutabaga | NR | Spore suspension (2.5 ml) added to 500 g sample. | 1-inch cubes, inoculated and sealed in polystyrene tray. | 15 25 |
2.0 2.0 |
21 d | NR | spores/g | No toxin detected after 21 d (15°C). No change in appearance. At 25°C toxin detected at 7 d. decay evident. Final pH 5.9. | Austin and others 1998 |
| C. botulinum nonproteolytic (8 strains) |
Stir fry vegetables | NR | Spore suspension (1 ml) injected into sealed bags through gas-tight septum. | Stored in plastic film. | 5 10 |
3.0 3.0 |
21 d | 3.0 3.3 |
CFU/g | No toxin detected after 21 d. No change in appearance. | Austin and others 1998 |
| C. botulinum proteolytic (10 strains) |
Stir fry vegetables | NR | Spore suspension (1 ml) injected into sealed bags through gas-tight septum. | Stored in plastic film. | 15 | 2.0 | 21 d | 2.8 | CFU/g | No toxin detected at 21 d. No change in appearance. | Austin and others 1998 |
| C. botulinum proteolytic (10 strains) |
Stir fry vegetables | NR | Spore suspension (1 ml) injected into sealed bags through gas-tight septum. | Stored in plastic film. | 25 | 2.0 | 11 d | >4.5 | CFU/g | Toxin detected at 11 d. Soft appearance. Final pH 4.2. | Austin and others 1998 |
| Escherichia coli O157:H7 (5 strains) | Carrot (shredded) | 7.1 | Dip inoculation, 1 min. Cells suspended in deionized water. | Stored in polyolefin L-bags consisting 3% O2 and 97% N2. | 5 12 21 |
2.5 | 3 d 3 d 7 d |
<1 <1 4.2 |
CFU/g | Samples held at 5°C and 12°C were positive upon enrichment through day 14. | Abdul-Raouf and others 1993 |
| E. coli O157:H7 (5 strains) | Carrot (shredded) | 7.1 | Dip inoculation, 1 min. Cells suspended in deionized water. | Stored in air in polyolefin L-bags. | 5 12 21 |
5.3 | 3 d 14 d 7 d |
4.6 6.3 6.0 |
CFU/g | Samples held at 5°C were positive upon enrichment through day 14. | Abdul-Raouf and others 1993 |
| E. coli O157:H7 (5 strains) | Carrot (shredded) | 7.1 | Dip inoculation, 1 min. Cells suspended in deionized water. | Stored in air in polyolefin L-bags. | 5 12 21 |
2.5 | 3 d 3 d 7 d |
<1 <1 3.8 |
CFU/g | Samples held at 5°C and 12°C were positive upon enrichment through day 14. | Abdul-Raouf and others 1993 |
| E. coli O157:H7 (5 strains) | Carrot (shredded) | 7.1 | Dip inoculation, 1 min. Cells suspended in deionized water. | Stored in polyolefin L-bags consisting 3% O2 and 97% N2. | 5 12 21 |
5.3 | 3 d 14 d 7 d |
4.1 6.6 6.5 |
CFU/g | Samples held at 5°C were positive upon enrichment through day 14. | Abdul-Raouf and others 1993 |
| E. coli O157:H7 (5 strains) | Cucumber (sliced) | 7.3 | Dip inoculation, 1 min. Cells suspended in deionized water. | 5-mm discs, stored in 3% O2 and 97% N2 in polyolefin L-bags. | 5 12 21 |
5.1 | 10 d 10 d 7 d |
2.3 5.4 4.6 |
CFU/g | - | Abdul-Raouf and others 1993 |
| E. coli O157:H7 (5 strains) | Cucumber (sliced) | 7.3 | Dip inoculation, 1 min. Cells suspended in deionized water. | 5-mm discs, stored in 3% O2 and 97% N2 in polyolefin L-bags. | 5 12 21 |
2.3 | 3 d 3 d 7 d |
<1 <1 2.6 |
CFU/g | Samples stored at 5 and 12°C were positive upon enrichment through day 3 and day 7, respectively. | Abdul-Raouf and others 1993 |
| E. coli O157:H7 (5 strains) | Cucumber (sliced) | 7.3 | Dip inoculation, 1 min. Cells suspended in deionized water. | 5-mm discs, stored in air in polyolefin L-bags. | 5 12 21 |
5.1 | 10 d 10 d 7 d |
3.4 5.7 2.6 |
CFU/g | - | Abdul-Raouf and others 1993 |
| E. coli O157:H7 (5 strains) | Cucumber (sliced) | 7.3 | Dip inoculation, 1 min. Cells suspended in deionized water. | 5-mm discs, stored in air in polyolefin L-bags. | 5 12 21 |
2.3 | 3 d 3 d 7 d |
<1 <1 3.1 |
CFU/g | Samples stored at 5 and 12°C were positive upon enrichment through day 3 and day 10, respectively. | Abdul-Raouf and others 1993 |
| Listeria monocytogenes (1 strain) |
Asparagus | NR | Cells injected into samples. | Stored in hemetically sealed bags. | 2 4 8 12 20 |
5.0 5.0 5.0 5.0 5.0 |
6-24 d 6-24 d 3-24 d 3-15 d 3-6 d |
4.5 5.0 7.0 9.0 9.0 |
CFU/g CFU/g CFU/g CFU/g CFU/g |
Approximately 1 log increase at 2 and 4°C within 3 d followed by decrease. | Castillejo Rodriguez and others 2000 |
| L. monocytogenes (2 strains) | Asparagus | NR | Dip inoculation, 1 min. Cells suspended in 0.1M potassium phosphate buffer. | Samples stored in 6% CO2, 79% N2, and 15% O2 in glass jars. | 15 4 |
4.0/4.8 4.2/4.8 |
6 d 21 d |
~7.3 ~5.8/6.5 |
CFU/g CFU/g | Asparagus first became unacceptable for consumption on day 6 (15°C) or day 21 (4°C). | Berrang and others 1989b |
| L. monocytogenes (2 strains) | Asparagus | NR | Dip inoculation, 1 min. Cells suspended in 0.1M potassium phosphate buffer. | Samples stored in ambient air in glass jars. | 15 4 |
4.0/4.8 4.2/4.8 |
4 d 14 d |
~7.0 ~5.0/5.5 |
CFU/g CFU/g | Asparagus first became unacceptable for consumption on day 4 (15°C) or day 14 (4°C). | Berrang and others 1989b |
| L. monocytogenes (2 strains) | Broccoli | NR | Dip inoculation, 1 min. Cells suspended in 0.1M potassium phosphate buffer. | Samples stored in 10% CO2, 79% N2, and 11% O2 in glass jars. | 15 4 |
5.0/5.5 4.0 |
10 d 21 d |
~8.8 ~4.0/4.5 |
CFU/g CFU/g | Broccoli first became unacceptable for consumption on day 10 (15°C) or day 21 (4°C). | Berrang and others 1989b |
| L. monocytogenes (2 strains) | Broccoli | NR | Dip inoculation, 1 min. Cells suspended in 0.1 M potassium phosphate buffer. | Samples stored in ambient air in glass jars. | 15 4 |
5.6 4.0 |
10 d 21 d |
~8.7 ~3.8/4.0 |
CFU/g CFU/g | Broccoli first became unacceptable for consumption on day 6 (15°C) or day 14 (4°C). | Berrang and others 1989b |
| L. monocytogenes (5 strains) |
Butternut squash | 6.3 | Cell suspension, 10 ml of cells added to sample. Cells suspended in 0.1% peptone. | 2.5-cm cubes, inoculated, and transferred to a foam tray. Sealed and stored in a bag. | 4 10 |
3.0 | 9 d | ~6.5 ~8.5 |
CFU/g | - | Farber and others 1998 |
| L. monocytogenes (1 strain) | Cabbage (shredded) | NR | Cells suspended in Butterfield's phosphate buffer, 1 ml added to sample. | Samples in stored gas impermeable plastic bags and sealed in ambient atmosphere. | 5 | 3.6 | 13 d/17 d | 4.6/2.1 | CFU/g | - | Kallander and others 1991 |
| L. monocytogenes (1 strain) | Cabbage (shredded) | NR | Cells suspended in Butterfield's phosphate buffer, 1 ml added to sample. | Samples in stored gas impermeable plastic bags and sealed in 70% CO2 and 30% N2. held refrigerated for first 24 h. | 5 | 3.0 | 17 d | ~4.9 | CFU/g | - | Kallander and others 1991 |
| L. monocytogenes (1 strain) | Cabbage (shredded) | 6.32 (day 1) | Cells suspended in Butterfield's phosphate buffer, 1 ml added to sample. | Samples in stored gas impermeable plastic bags and sealed in ambient atmosphere. held refrigerated for first 24 h. | 25 | 4.1 | 2 d/6-9 d | ~6.0/<1.3 | CFU/g | - | Kallander and others 1991 |
| L. monocytogenes (1 strain) | Cabbage (shredded) | 6.32 (day 1) | Cells suspended in Butterfield's phosphate buffer, 1 ml added to sample. | Samples stored in gas impermeable plastic bags and sealed in 70% CO2 and 30% N2. | 25 | 4.0 | 2 d/6-9 d | ~4.5/<1.3 | CFU/g | - | Kallander and others 1991 |
| L. monocytogenes (1 strain) |
Cabbage (shredded) | NR | Cells suspended in 0.1M potassium phosphate buffer and added to sample. | Samples were mixed, drained and adjusted to incubation temperature within 3 h. | 5 | 4.0 | 25-64 d | ~8.0 | CFU/g | - | Beuchat and others 1986 |
| L. monocytogenes (5 strains) |
Carrot | NR | Cell suspension, 1 to1.6 ml of inoculum injected through a gas-tight septum. Cells suspended in 0.1% peptone. | Samples purchased from the store. Stored in original packaging. | 4 10 |
2.3 2.3 |
9 d 9 d |
1.0 <1.0 |
CFU/g | - | Farber and others 1998 |
| L. monocytogenes (2 strains) | Carrot (shredded) | - | Dip inoculation, cells suspended in 0.1 M potassium phosphate buffer. | Carrots washed or unwashed in 200-250 ppm prior to shredding. Stored in ambient air or in 3% O2 and 97% N2. | 5 15 |
1.1-2.6 <1.0 |
24 d 7 d |
3.8-4.6 3.4-5.8 |
CFU/g | Similar results obtained for unwashed carrots stored at 5°C. Population declined to <1 log CFU/g (day 7) in unwashed carrots stored at 15°C. | Beuchat and Brackett 1990a |
| L. monocytogenes (2 strains) | Carrot (whole) | - | Dip inoculation, cells suspended in 0.1 M potassium phosphate buffer. | Carrots washed or unwashed in 200-250 ppm. Stored in ambient air or in 3% O2 and 97% N2. | 5 15 |
1.8-2.4 2.5-3.0 |
18 d 7 d |
<1.0 <1.0 |
CFU/g | - | Beuchat and Brackett 1990a |
| L. monocytogenes (2 strains) | Cauliflower | NR | Dip inoculation, 1 min. Cells suspended in 0.1 M potassium phosphate buffer. | Samples stored in 3% CO2, 79% N2, and 18% O2 in glass jars. | 15 4 |
3.4/4.0 2.8/ 3.0 |
8 d 21 d |
~6.8/7.1 ~3.0/3.6 |
CFU/g CFU/g | Cauliflower first became unacceptable for consumption on day 8 (15°C) or day 21 (4°C). | Berrang and others 1989b |
| L. monocytogenes (2 strains) | Cauliflower | NR | Dip inoculation, 1 min. Cells suspended in 0.1 M potassium phosphate buffer. | Samples stored in ambient air in glass jars. | 15 4 |
3.4/4.0 2.8/ 3.0 |
8 d 14 d |
~6.2/6.8 ~2.3/3.6 |
CFU/g CFU/g | Cauliflower first became unacceptable for consumption on day 6 (15°C) or day 14 (4°C). | Berrang and others 1989b |
| L. monocytogenes (5 strains) |
Coleslaw | 6.6 | Cell suspension, 1 to1.6 ml of inoculum injected through a gas-tight septum. Cells suspended in 0.1% peptone. | Samples were purchased from the store. Stored in original packaging. | 4 10 |
2.5 2.5 |
9 d | ~4.0 ~5.0 |
CFU/g | - | Farber and others 1998 |
| L. monocytogenes (1 strain) |
Endive (chicory) | NR | Cell suspension added to samples. | Stored in moderate vacuum packaging containers under moderate vacuum. | 6.5 | 3.3 | 7 d | ~2.5 | CFU/g | - | Aytac and Gorris1994 |
| L. monocytogenes (1 strain) |
Endive (chicory) | NR | Cell suspension added to samples. | Stored in moderate vacuum packaging container in ambient air. | 6.5 | 3.3 | 7 d | ~5.2 | CFU/g | - | Aytac and Gorris1994 |
| L. monocytogenes (1 strain) | Endive (broad leaved) | - | Dip inoculation, 10 min. Cells suspended in sterile distilled water. | Samples were inoculated, drained, sealed, and stored in polypropylene pouches. | 10 | 4.5 | 7 d | 5.2 | CFU/g | - | Carlin and Nguyen-the 1994 |
| L. monocytogenes (1 strain) | Endive (curly leaved) | - | Dip inoculation, 10 min. Cells suspended in sterile distilled water. | Samples were inoculated, drained, sealed, and stored in polypropylene pouches. | 10 | 4.2 | 7 d | 4.5 | CFU/g | - | Carlin and Nguyen-the 1994 |
| L. monocytogenes (3 strains) | Endive (broad leaved) | NR | Dip inoculation, 10 min. Cells suspended in sterile distilled water. Strains inoculated independently. | Samples were inoculated, drained, sealed, and stored in polypropylene pouches. | 10 | 4.1-4.8 | 7 d | 6.1-7.0 | CFU/g | When lower inoculation levels were used, populations inccreased faster during initial storage but final populations were lower. | Carlin and others 1995 |
| L. monocytogenes (3 strains) | Endive (broad leaved) | NR | Dip inoculation, 10 min. Cells suspended in sterile distilled water. | Stored in 90-mm diameter petri dishes and placed in plastic boxes. Boxes contained wet absorbent paper. Stored in modified atmosphere of 10% CO2, 10% O2. | 3 10 |
~3.9-4.0 ~4.1-4.2 |
10 d 8 d |
~3.5-4.5 ~6.2-6.7 |
CFU/g | Higher initial CO2 levels caused significant spoilage. | Carlin and others 1996 |
| L. monocytogenes (3 strains) | Endive (broad leaved) | NR | Dip inoculation, 10 min. Cells suspended in sterile distilled water. | Stored in 90-mm diameter petri dishes and placed in plastic boxes. Boxes contained wet absorbent paper. Stored in ambient air. | 3 10 |
~3.6-3.9 ~4.1-4.2 |
10 d 8 d |
~4.0-5.0 ~6.2-6.7 |
CFU/g | - | Carlin and others 1996 |
| L. monocytogenes (5 strains) |
Onion | 5.8 | Cell suspension, 10 ml of cells added to sample. Cells suspended in 0.1% peptone. | 1-cm slices, inoculated, and transferred to foam trays. Sealed and stored in bags. | 4 10 |
4.0 3.5 |
9 d | ~3.0 ~4.8 |
CFU/g | - | Farber and others 1998 |
| L. monocytogenes (5 strains) |
Rutabaga | 6.3 | Cell suspension, 10 ml of cells added to sample. Cells suspended in 0.1% peptone. | 0.5 by 0.5 by 7.5cm sticks, inoculated, and transferred to foam trays. Stored and sealed in bags. | 4 10 |
3.0 3.0 |
9 d | ~4.0 ~6.0 |
CFU/g | - | Farber and others 1998 |
| L. monocytogenes (5 strains) |
Stir fry vegetables | 6.8 | Cell suspension, 1-1.6 ml of inoculum injected through a gas-tight septum. Cells suspended in 0.1% peptone. | Samples purchased from the store. Stored in original packaging. | 4 10 |
2.5 2.5 |
9 d | ~3.0 ~5.5 |
CFU/g | - | Farber and others 1998 |
| Samonella Typhi | Jicama (cubes) | 3.30 | Spot inoculation, cells suspended in saline. 1 drop (Pasteur pipette) inoculated per cube. | 12 cm2 cubes, 0.05 ml lemon juice added, inoculated, and stored in covered glass trays. | 25-27 | 3.1 | 6 h | 3.4 | CFU/cube | - | Fernandez Escartin and others 1989 |
| S. Typhi | Jicama (cubes) | 5.97 | Spot inoculation, cells suspended in saline. 1 drop (Pasteur pipette) inoculated per cube. | 12 cm2 cubes, inoculated, and stored in covered glass trays. | 25-27 | 3.2 | 6 h | 4.7 | CFU/cube | - | Fernandez Escartin and others 1989 |
| Shigella dysenteriae (1 strain) |
Jicama (cubes) | 5.97 | Spot inoculation, cells suspended in saline. 1 drop (Pasteur pipette) inoculated per cube. | 12 cm2 cubes, inoculated and stored in covered glass trays. | 25-27 | 1.5 | 6 h | 2.2 | CFU/cm2 | - | Fernandez Escartin and others 1989 |
| S. flexneri (1 strain) |
Carrot salad | NR | Cells suspended in water and added to sample. | Samples stored in 50 ml polypropylene centrifuge tubes. | 5 | ~6.7 | 11 d | ~2.5 | CFU/g | - | Rafii and Lunsford 1997 |
| S. flexneri (1 strain) |
Green pepper (chopped) | NR | Cells suspended in water and added directly to sample. | Samples stored in 50 ml polypropylene centrifuge tubes. | 4 | 6.7 | 12 d | 4.3 | CFU/g | - | Rafii and Lunsford 1997 |
| S. flexneri (1 strain) |
Coleslaw | NR | Cells suspended in water and added directly to sample. | Samples stored in 50 ml polypropylene centrifuge tubes. | 4 | ~5.1 | 16 d | ~4.3 | CFU/g | - | Rafii and Lunsford 1997 |
| S. flexneri (1 strain) |
Cabbage (chopped) | NR | Cells suspended in water, added directly to sample. | Samples stored in 50 ml polypropylene centrifuge tubes. | 4 | 6.5 | 26 d | 3.1 | CFU/g | - | Rafii and Lunsford 1997 |
| S. flexneri (1 strain) | Onion (chopped) | NR | Cells suspended in water and added to sample. | Samples stored in 50 ml polypropylene centrifuge tubes. | 4 | 6.7 | 12 d | 5.3 | CFU/g | - | Rafii and Lunsford 1997 |
| S. sonnei | Parsley (chopped leaves) | NR | Parsley was immersed in suspension of cells in 0.05 M potassium phosphate buffer (pH 6.8) for 1 min while being agitated, then dried at 21°C for 1 h. | Leaves (300 g) placed in 9-liter pans. | 21 | 3.5 | 1 d | 6.2 | CFU/g | Subjective examination revealed that parsley was edible. | Wu and others 2000 |
| S. sonnei | Parsley (whole leaves) | NR | Parsley was immersed in suspension of cells in 0.05 M potassium phosphate buffer (pH 6.8) for 1 min while being agitated, then dried at 21°C for 1 h. | Leaves (300 g) placed in 9-liter pans. | 21 | 3.2 | 7 d | 3.8 | CFU/g | Subjective examination revealed that parsley was edible. | Wu and others 2000 |
| S. sonnei | Parsley (whole or chopped leaves) | NR | Parsley was immersed in suspension of cells in 0.05 M potassium phosphate buffer (pH 6.8) for 1 min while being agitated, then dried at 21°C for 1 h. | Leaves (300 g) placed in 9-liter pans. | 4 | 3.2-3.5 | 14 d | 0.4-0.8 | CFU/g | Subjective examination revealed that parsley was edible. | Wu and others 2000 |
| S. sonnei (3 strains) |
Parsley (chopped) | - | Dip inoculation, cells suspended in 0.05 M potassium phosphate-buffered saline. 1200 g sample inoculated and dried. Chopped after drying. | Stored in 9-liter plastic pans. | 4 21 |
6.48/3.49 | 2 d | ~9.2/~6.3 | CFU/g | The pathogen grew to 9.2 and 6.3 log CFU/g within 2 d at 21°C, followed by a decline. Inoculated chopped parsley stored at 4°C declined throughout a 14 day storage period. | Wu and others 2000 |
| S. sonnei (3 strains) |
Parsley (whole, leaves) | - | Dip inoculation, cells suspended in 0.05 M potassium phosphate-buffered saline. 1200 g sample inoculated and dried. | Stored in 9-liter plastic pans. | 21 | 3.23/6.19 | 7 d/7 d | ~3.0/~6.5 | CFU/g | An increase of <1 log within 1 day at 21°C, followed by a decline in population after 2 d. Inoculated parsley stored at 4°C declined thoroughout the 14 day storage period. | Wu and others 2000 |
| S. sonnei (1 strain) |
Cabbage (shredded) | 6.8 | Dip inoculation, cells suspended in Butterfield's phosphate buffer. | Stored under vacuum in gas impermeable bags. | 24+ 2 0-6 |
3.2 3.5 |
1 d/7 d 7 d |
7.0/<-0.52 3.5 |
MPN/g | - | Satchell and others 1990 |
| S. sonnei (1 strain) |
Cabbage (shredded) | 6.8 | Dip inoculation, cells suspended in Butterfield's phosphate buffer. | Stored in modified atmosphere (30% N2, 70% CO2) in gas impermeable bags. | 24+ 2 0-6 |
3.4 2.6 |
1 d/7 d 7 d |
7.0/3.7 2.5 |
MPN/g | - | Satchell and others 1990 |
| S. sonnei (1 strain) |
Cabbage (shredded) | 6.8 | Dip inoculation, cells suspended in Butterfield's phosphate buffer. | Stored anaerobically in gas impermeable bags. | 24+ 2 0-6 |
3.6 3.8 |
2 d/7 d 7 d |
7.0/4.4 -0.081 |
MPN/g | - | Satchell and others 1990 |
| Shigella (3 species) |
Jicama (cubes) | 5.97 | Spot inoculation, cells suspended in saline. 1 drop (Pasteur pipette) inoculated per cube. | 12 cm2 cubes, inoculated and stored in covered glass trays. | 25-27 | 2.5-2.6 | 6 h | 3.3-4.0 | CFU/cm2 | S. sonnei, S. flexneri, S. dysenteriae |
Fernandez Escartin and others 1989 |
| aNot reported | |||||||||||
Table G/S-5: Survival and Growth of Pathogenic Bacteria on Raw Lettuce and Salads
| Pathogen | Produce Type | pH | Mode of Inoculation | Storage Conditions | Temperature (°C) | Initial Counts (log10 CFU) | Incubation Time | Final Counts (log10 CFU) | Unit | Comments | Reference |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Clostridium botulinum (10 strains) | Lettuce (intact) | 6.2 | Spot inoculation, spores prepared in broth, heat shocked, and diluted in distilled water. | Samples stored in polyethylene bags and vacuum sealed. | 4 12 21 |
2.0 | 50 d 13 d 6 d |
NR | NR | At 4°C, 0/6 toxic. At 12°C, 0/6 toxic. At 21°C, 2/6 toxic. Gross spoilage observed when toxin detected. | Larson and others 1997 |
| C. botulinum nonproteolytic (8 strains) |
Mixed salad | NRa | Spore suspension, 1 ml injected through gas-tight septum. | Samples in original package. | 5 10 15 25 |
3.0 | 21 d 21 d 14 d 4 d |
3.7 3.7 >4.5 >4.4 |
spores/g | No toxin at 5 or 10°C. Toxin detected at 14 d (15°C) and 4 d (25°C). Moderate browning at time of toxin detection. Final pH 5.3-5.9. | Austin and others 1998 |
| C. botulinun proteolytic (10 strains) |
Mixed salad | NR | Spore suspension, 1 ml injected through gas-tight septum. | Samples in original package. | 15 15 25 |
1.0 2.0 |
21 d 21 d 7 d |
NR NR >4.5 |
spores/g | No toxin at 15°C. Extensive decay observed when toxin detected (7 d at 25°C). | Austin and others 1998 |
| C. botulinum (12 strains) |
Romaine lettuce (shredded) | NR | Spore suspension (1 ml), heat shocked, sprayed onto sample. Spores were suspended in gel-phosphate buffer. | Samples were sealed in 3-qt pouches and stored vented or not vented. Vented bags were placed with space between samples so that air could circulate. | 4.4 12.7 21 |
2.0 2.0 2.0 |
28 d 28 d 28 d |
2.0 2.1 NDb |
MPN spores/g | No toxin detected in samples stored at 4.4°C or 12.7°C. Toxin detected in non-vented samples stored at 21°C after 14 d and in vented samples after 21 d. Samples were judge to be inedible prior to toxin detection. | Petran and others 1995 |
| C. botulinum nonproteolytic (8 strains) |
Romaine lettuce | NR | Spore suspension, 1 ml injected through gas-tight septum. | Samples in original package. | 5 10 |
3.0 | 21 d | NR | spores/g | Toxin not detected. No change in appearance. | Austin and others 1998 |
| C. botulinun proteolytic (10 strains) |
Romaine lettuce | NR | Spore suspension, 1 ml injected through gas-tight septum. | Samples packaged in film. | 15 15 25 |
1.0 2.0 |
21 d 21 d 9 d |
NR NR >4.5 |
spores/g | Toxin not detected at 15°C. No change in appearance. Extensive decay observed when toxin detected at 25°C. | Austin and others 1998 |
| Escherichia coli O157:H7 | Lettuce (shredded) | ~7.4 | Dip inoculation, 1 min. Cells suspended in deionized water. | Stored in polyolefin L-bags consisting 3% O2 and 97% N2. | 5 12 21 |
5.3 | 14 d 3 d/14 d 3 d/7 d |
3.1 7.0/8.0 8.5/8.7 |
CFU/g | - | Abdul-Raouf and others 1993 |
| E. coli O157:H7 | Lettuce (shredded) | ~7.4 | Dip inoculation, 1 min. Cells suspended in deionized water. | Stored in air in polyolefin L-bags. | 5 12 21 |
5.3 | 14 d 3 d/14 d 3 d/7 d |
4.2 6.8/7.5 8.5/8.8 |
CFU/g | - | Abdul-Raouf and others 1993 |
| E. coli O157:H7 | Iceberg lettuce (shredded) | NR | Dip inoculation (1 min) in 0.1 M phosphate buffer (pH 7.0) suspension before mild heat treatment (50°C, 90 s). | Stored in plastic bags for up to 18 d. | 5 | 3.4 | 18 d | 2.9 | CFU/g | Counts on heated lettuce were similar to counts on unheated lettuce. | Li and others 2001 |
| E. coli O157:H7 | Iceberg lettuce (shredded) | NR | Dip inoculation (1 min) in 0.1 M phosphate buffer (pH 7.0) suspension before mild heat treatment (50°C, 90 s). | Stored in plastic bags for up to 7 d. | 15 | 3.4 | 7 d | 7.6 | CFU/g | Counts on heated lettuce were significantly higher than counts on unheated lettuce stored for 4 and 7 d. | Li and others 2001 |
| E. coli O157:H7 | Iceberg lettuce (pieces) | Dip inoculation, 30 s. Cells suspended in trypticase soy broth. | Stored in sealed plastic bags. | 4 | ~3.9 | 4 | ~3.7 | CFU/g | - | Lin and others 2000 | |
| Listeria monocytogenes (1 strain) | Butterhead lettuce | NR | Dip inoculation, 10 mins. Cells suspended in sterile distilled water. | Samples were drained on absorbent paper, sealed, and stored in polypropylene pouches. | 10 | 4.4 | 7 d | 5.3 | CFU/g | - | Carlin and Nguyen-the 1994 |
| L. monocytogenes (5 strains) | Ceasar salad | 6.3 | Cells suspended in 0.1% peptone, 1-1.6 ml injected through a gas-tight septum. | Samples purchased from store, inoculated, and stored in original packaging. | 4 10 |
~3.0 ~3.0 |
9 d | ~3.0 ~6.0 |
CFU/g | - | Farber and others 1998 |
| L. monocytogenes (1 strain) |
Lettuce (pieces) | NR | Inoculated with contaminated gloved hands. Inoculum diluted in sterile water. | Stored in sealed plastic bags. | 5 12 25 |
5.4 3.8 4.6 |
14 d 14 d 14 d |
6.5 6.9 5.9 |
CFU/g | Levels of L. monocytogenes estimated by randomly selecting 5 colonies from plate count agar and streaking onto McBride Listeria Agar. | Steinbruegge and others 1988 |
| L. monocytogenes (2 strains) | Lettuce (shredded) | NR | Dip inoculation, 1 min. Cells suspended in 0.1 M phosphate buffer. | Produce washed in 200-250ppm chlorine and stored in Cryvovac L-bags in 3% O2 and 97% N2. | 5 10 |
4.1 4.2 |
15 d 10 d |
~5.0 ~8.0 |
CFU/g | - | Beuchat and Brackett 1990b |
| L. monocytogenes (2 strains) | Lettuce (shredded) | NR | Dip inoculation, 1 min. Cells suspended in 0.1 M phosphate buffer. | Produce not washed and stored in Cryvovac L-bags in 3% O2 and 97% N2. | 5 10 |
4.8 4.8 |
15 d 10 d |
~4.8 ~7.7 |
CFU/g | - | Beuchat and Brackett 1990b |
| L. monocytogenes (2 strains) | Lettuce, whole leaves | NR | Dip inoculation, 1 min. Cells suspended in 0.1 M phosphate buffer. | Produce not washed and stored in Cryvovac L-bags in 3% O2 and 97% N2. | 5 10 |
4.6 4.7 |
15 d 10 d |
5.4 6.8 |
CFU/g | - | Beuchat and Brackett 1990b |
| L. monocytogenes (2 strains) | Lettuce, whole leaves | NR | Dip inoculation, 1 min. Cells suspended in 0.1M phosphate buffer. | Produce washed in 200-250ppm chlorine and stored in Cryvovac L-bags in 3% O2 and 97% N2. | 5 10 |
4.3 4.7 |
15 d 10 d |
4.9 6.8 |
CFU/g | - | Beuchat and Brackett 1990b |
| L. monocytogenes (1 strain) | Lamb's lettuce | NR | Dip inoculation, 10 mins. Cells suspended in sterile distilled water. | Samples were drained on absorbent paper, sealed, and stored in polypropylene pouches. | 10 | 4.1 | 7 d | 4.0 | CFU/g | - | Carlin and Nguyen-the 1994 |
| L. monocytogenes | Iceberg lettuce (pieces) | Dip inoculation, 30 s. Cells suspended in trypticase soy broth. | Stored in sealed plastic bags. | 4 | ~4.1 | 4 | ~4.4 | CFU/g | - | Lin and others 2000 | |
| Salmonella Baildon | Iceberg lettuce (shredded) | 6.06-7.00 | Cells suspended in deionized water, 30 ml mixed with 2270 g of lettuce. | Lettuce (450g) was sealed in plastic bags. Stored for up to 12 d. | 4 | 0.3 | 12 d | <1.0 | CFU/g | Detected in 6 of 6 enriched samples (25 g) after 2, 5, and 8 d, and 1 of 6 samples after 12 d. | Weissinger and others 2000 |
| S. Baildon | Iceberg lettuce (shredded) | 6.06-7.00 | Cells suspended in deionized water; 30 ml mixed with 2270 g of lettuce. | Lettuces (450g) was sealed in plastic bags. Stored for up to 12 d. | 4 | 3.3 | 12 d | 1.8 | CFU/g | Counts were 3.24, 3.07, and 2.69 log10 CFU/g after 2, 5, and 8 d, respectively. | Weissinger and others 2000 |
| S. Montevideo | Iceberg lettuce (pieces) | Dip inoculation 30 s. Cells suspended in trypticase soy broth. | Stored in sealed plastic bags. | 4 | ~4.1 | 4 | ~4.4 | CFU/g | - | Lin and others 2000 | |
| Shigella sonnei | Lettuce (shredded) | NR | Spot inoculated. | Strain isolated from outbreak and inoculated onto lettuce. | 5 | NR | 7 d |
1 log decrease | CFU/g | - | Davis and others 1988 |
| S. sonnei | Lettuce (shredded) | NR | Spot inoculated. | Strain isolated from outbreak and inoculated onto lettuce. | 15 | 3.1 | - | - | CFU/g | 5 h generation time. | Davis and others 1988 |
| S. sonnei (1 strain) |
Lettuce (shredded) | NR | Spot inoculated. | Strain isolated from outbreak and inoculated onto lettuce. | 22 | 3.1 | 12 h | 6.3 | CFU/g | S. sonnei survived but did not grow at 5 and 15°C. | Davis and others 1988 |
| aNot reported bNot determined |
|||||||||||
Table G/S-6: Survival and Growth of Pathogenic Bacteria in Unpasteurized Juice
| Pathogen | Juice Type | pH | Mode of Inoculation | Conditions | Temperature (°C) | Initial Counts (log10 CFU) | Incubation Time | Final Counts (log10 CFU) | Unit | Comments | Reference |
|---|---|---|---|---|---|---|---|---|---|---|---|
| Escherichia coli O157:H7 (1 strain) |
Apple, cider | 3.7 | Cells suspended in 0.85% NaCl solution, 1 ml added to 100 ml sample. | Full strength apple cider. Stored in flask on a shaker at 150 rpm. | 26 | 6 | 6 d | 4.5 | CFU/ml | - | Janisiewicz and others 1999 |
| E. coli O157:H7 | Apple, cider | 3.6-4.0 | Cells suspended in 0.1 M phosphate buffered saline, 0.5 ml added to sample. | 6 different lots of apple cider used. | 8 | 5.0 | 15-34 d | <1.0 | CFU/ml | Populations initially increased slightly, remained stable through day 12 then decreased to undetectable levels. Growth was questioned by authors. Addition of sodium benzoate (0.1%) resulted in more rapid decline (undetectable between day 3-15). | Zhao and others 1993 |
| E. coli O157:H7 | Apple, cider | 3.6-4.0 | Cells suspended in 0.1 M phosphate buffered saline, 0.5 ml added to sample. | 6 different lots of apple cider used. | 8 | 2.0 | 11-15 d | <1.0 | CFU/ml | Steady population decline. | Zhao and others 1993 |
| E. coli O157:H7 (2 strains) | Apple, cider (filter sterilized) | 3.5 | Culture grown in tryptic soy broth, added to sample. | Inoculum grown in apple juice adjusted to pH 6.5. | 21 4 |
~5.3 | 7 d 7 d |
<1.5 2.2 |
CFU/ml | - | Uljas and Ingham 1998 |
| E. coli O157:H7 | Apple, cider | 3.6-4.0 | Cells suspended in 0.1 M phosphate buffered saline, 0.5 ml added to sample. | 6 different lots of apple cider used. | 25 | 5.0 | 3-6 d | <1.0 | CFU/ml | Initial increase in population 24-48 h followed by decline. Growth was questioned by authors. higher numbers achieved in higher pH juice. More rapid decline when yeast levels were high. | Zhao and others 1993 |
| E. coli (O157:H7) | Apple, cider | 3.6-4.2 | NR | Room temperature for up to 11 d. | 20-25°C | 4.3 | 7 d | 2.5 - 41 | CFU/ml | Rate of inactivation in cider from McIntosh apples was more rapid than in cider from Red delicious, Golden delicious, or Melrose apples. | Dingman 2000 |
| E. coli O157:H7 | Apple, juice | 3.70 | Cells suspended in 0.85% NaCl solution, 1 ml added to sample. | Full strength apple juice. Stored in flask on a shaker at 150 rpm. | 26 | 6.0 | 6 d | 5.5 | CFU/ml | - | Janisiewicz and others 1999 |
| E. coli O157:H7 | Apple, juice | 3.62 | Cells suspended in 0.85% NaCl solution, 1 ml added to sample. | Juice diluted with 50% water. Stored in flask on a shaker at 150 rpm. | 26 | 6.0 | 6 d | 5.0 | CFU/ml | - | Janisiewicz and others 1999 |
| E. coli O157:H7 | Apple, juice | 3.55 | Cells suspended in 0.85% NaCl solution, 1 ml added to sample. | Juice diluted with 75% water. Stored in flask on a shaker at 150 rpm. | 26 | 6.0 | 6 d | 4.5 | CFU/ml | - | Janisiewicz and others 1999 |
Table G/S-7: Survival and Growth of Pathogenic Organism on Sprout Seeds or Raw Sprouts
| Pathogen | Produce Type | Mode of Inoculation | Storage Conditions | Temperature (°C) | Initial Counts (log10 CFU) | Incubation Time | Final Counts (log10 CFU) | Unit | Comments | Reference |
|---|---|---|---|---|---|---|---|---|---|---|
| Aeromonas hydrophila | Sprouts, mung bean | Diluted suspension inoculated onto sprouts. | Stored in rigid plastic containers, 400 mB. | 6.5 | 5.0 | 5 d | ~6.8 | CFU/g | Sprouts obtained from local retail market. | Aytac and Gorris 1994 |
| A. hydrophila | Sprouts, mung bean | Diluted suspension inoculated onto sprouts. | Stored in rigid plastic containers. | 6.5 | 5.0 | 7 d | ~9.2 | CFU/g | Sprouts obtained from local retail market. | Aytac and Gorris1994 |
| Escherichia coli O157:H7 (5 strains) |
Seeds, alfalfa | Dip inoculation 1 min. Cells suspended in deionized water. | Inoculated seeds were dried (5.1-6.2% moisture) before storage in sealed containers. | 5 | 3 | 54 weeks | <0.3 | CFU/g | Counts decreased to 1.5 log10 CFU/g within 38 weeks. detected by enrichment at 54 weeks. | Taormina and Beuchat 1999b |
| E. coli O157:H7 (5 strains) | Seeds, alfalfa | Dip inoculation, 1 min. Cells suspended in deionized water. | Inoculated seeds were dried (5.1-6.2% moisture) before storage in sealed containers. | 25 | 3 | 54 weeks | <0.3 | Counts decreased to 0.74 and <0.3 log10 CFU/g after 8 and 12 weeks, respectively. detected by enrichment after 38 weeks but not 54 weeks. | Taormina and Beuchat 1999b | |
| E. coli O157:H7 (5 strains) | Seeds, alfalfa | Dip inoculation, 1 min. Cells suspended in deionized water. | Inoculated seeds were dried (5.1-6.2% moisture) before storage in sealed containers. | 37 | 3 | 54 weeks | <0.3 | Counts decreased and <0.3 log10 CFU/g within 8 weeks. detected by enrichment after 38 weeks, but not 54 weeks. | Taormina and Beuchat 1999b | |
| E. coli O157:H7 (5 strains) | Sprouts, alfalfa | Dip inoculation of seeds, 1 min. Cells suspended in Butterfield's phosphate buffer. | Counts were monitored during sprout production in glass jars. | 25 | NR | 5 d | 7.1-8.0 | CFU/g | Seeds were treated with disinfectants before sprouting. | Lang and others 2000 |
| E. coli O157:H7 (5 strains) | Sprouts, alfalfa | Dip inoculation of seeds, 1 min. Cells suspended in deionized water. Sprouts produced from inoculated, dried seeds. | Counts were monitored during sprout production in plastic boxes. | 21 | 2.3 | 72 h | 7.1 | CFU/g | Sprouts contained 7.4 and 7.2 log10 CFU/g after 24 and 48 h, respectively. | Taormina and Beuchat 1999a |
| E. coli O157:H7 | Sprouts alfalfa | Dip inoculation of seeds, 10 min. Cells suspended in 0.1% peptone. | Counts were monitored during sprout production in covered trays. | 22 | 3.1 | 10 d | 5.7 | CFU/g | Counts reached ca. 5.8 log10 CFU/g within 2 d. | Castro-Rosas and Escartin 2000 |
| E. coli O157:H7 (5 strains) | Sprouts alfalfa | Sprouts were produced at 21°C from inoculated seeds containing 2.7 log10 CFU/g. | Stored in closed plastic boxes. | 9 | 6.0-6.9 | 12 d | 5.6-6.5 | CFU/g | Subjective evaluation revealed sprouts were edible. | Taormina and Beuchat 1999a |
| Salmonella (5 serotypes) |
Sprouts alfalfa | Spot inoculation (0.1 ml) of 10 g of sprouts. Cells were suspended in 0.05 M phosphate buffer (pH 6.8). | Stored in closed clear plastic boxes. | 10 | 7.7 | 11 d | 6.9 | CFU/g | Sprouts were subjectively judged to be edible after 11 d. | Weissinger and others 2001 |
| S. Stanley | Seeds, alfalfa | Dip inoculation 1 min. Cells suspended in deionized water. | Inoculated seeds were dried before storage in sealed containers. | 8, 21 | 2.5 | 9 weeks | 1.81 | CFU/g | Seeds stored at 8°C for 9 weeks, then 21°C for 8 weeks contained 0.92 log10 CFU/g. | Jaquette and others 1996 |
| S. Stanley | Alfalfa seeds | Dip inoculation, cells suspended in 30 ml deionized water, seeds added to suspension and mixed for 1 min. | Seeds placed on wire screens, dried under a laminar flow hood for 24 h. Seeds stored in plastic bags at 21°C for 48 h and then stored at 8°C. | 21 | 2.5 | 8 weeks | 0.9 | CFU/g | - | Jaquette and others 1996 |
| S. Typhi | Sprouts, alfalfa | Dip inoculation of seeds, 10 min. Cells suspended in 0.1% peptone. | Counts were monitored during sprout production in covered trays. | 22 | 2.5 | 6 d | 3.7 | CFU/g | Counts increased to ca. 6.1 log10 CFU/g within 1 d, then decreased through 6 d. | Castro-Rosas and Escartin 2000 |
| S. Typhi | Sprouts, alfalfa | Dip inoculation of seeds, 10 min. Cells suspended in 0.1% peptone. Sprouts produced at 22°C for 7 d. | Stored in closed trays. | 4-7 | 4.8 | 15 d | 4.5 | CFU/g | Decreases have no practical significance to safety. | Castro-Rosas and Escartin 2000 |
| S. Typhi | Sprouts alfalfa | Seeds were germinated for 24 h, then inoculated with cells suspended in 0.1% peptone. | Counts were monitored during sprout production in covered trays. | 22 | 3.4 | 8 d | 2.4 | CFU/g | Counts decreased by ca. 1 log10, suggesting inability to compete with aerobic microorganisms, which were present at 7.5 log10 CFU/g when sprouts were inoculated with S. Typhi. | Castro-Rosas and Escartin 2000 |
| Vibrio cholerae | Sprouts, alfalfa | Dip inoculation of seeds, 10 min. Cells suspended in 0.1% peptone. | Counts were monitored during sprout production in covered trays. | 22 | 2.5 | 6 d | 3.7 | CFU/g | Counts increased to ca. 5.8 log10 CFU/g within 1 d, then decreased through 6 d. | Castro-Rosas and Escartin 2000 |
| V. cholerae | Sprouts alfalfa | Seeds were germinated for 24 h, then inoculated with cells suspended in 0.1% peptone. | Counts were monitored during sprout production in covered trays. | 22 | 2.5 | 8 d | 0.5 | CFU/g | Counts decreased by ca. 2 log10, suggesting inability to compete with aerobic microorganisms, which were at 7.5 log10 CFU/g when sprouts were inoculated with V. cholerae. | Castro-Rosas and Escartin 2000 |
| V. cholerae | Sprouts, alfalfa | Dip inoculation of seeds, 10 min. Cells suspended in 0.1% peptone. Sprouts produced at 22°C for 7 d. | Stored in closed trays. | 4-7 | 3.1 | 15 d | 2.1 | CFU/g | Decreases have no practical significance to safety. | Castro-Rosas and Escartin 2000 |
Table G/S-8: Survival of Pathogenic Viruses on Raw Produce
| Pathogen | Produce Type | Mode of Inoculation | Storage Conditions | Temperature (°C) | Initial Counts (log10 CFU) | Incubation Time | Final Counts (log10 CFU) | Unit | Comments | Reference |
|---|---|---|---|---|---|---|---|---|---|---|
| Coxsackie virus B5 | Carrot, whole | 0.05 ml spot inoculated onto sample. Virus suspended in water. | Samples were left uncovered. | 4 | ~2.6 | 1 d 5 d |
~1.6 <0.6 |
PFU/sample | Presence of moisture improved survival. Survival significantly better in closed containers with high humidity. Presence of feces improved survival. | Konowalchuk and Speirs 1975 |
| Coxsackie virus B5 | Carrot, whole | 0.05 ml spot inoculated onto sample. Virus suspended in dilute feces (1%). | Samples were left uncovered. | 4 | ~2.6 | 1 d 5 d |
~1.7 ~1.2 |
PFU/sample | Presence of moisture improved survival. Survival significantly better in closed containers with high humidity. Presence of feces improved survival. | Konowalchuk and Speirs 1975 |
| Coxsackie virus B5 | Carrot, whole | Spot inoculation, 0.05 ml inoculated onto sample. Virus suspended in undiluted feces. | Samples were left uncovered. | 4 | ~2.6 | 1 d 5 d |
~1.9 ~1.4 |
PFU/sample | Presence of moisture improved survival. Survival significantly better in closed containers with high humidity. Presence of feces improved survival. | Konowalchuk and Speirs 1975 |
| Coxsackie virus B5 | Celery | 0.05 ml spot inoculated onto sample. Virus suspended in water or dilute feces (1%). | Samples were enclosed in polyethylene bags which contained a dish of water to maintain humidity. | 4 | ~2.6 | 8 d | ~2.6 | PFU/sample | Presence of moisture improved survival. Survival significantly better in closed containers with high humidity. Presence of feces improved survival. | Konowalchuk and Speirs 1975 |
| Coxsackie virus B5 | Celery | 0.05 ml spot inoculated onto sample. Virus suspended in water or dilute feces (1%). | Samples were left uncovered. | 4 | ~2.6 | 1 d | ~2.0 | PFU/sample | Presence of moisture improved survival. Survival significantly better in closed containers with high humidity. Presence of feces improved survival. | Konowalchuk and Speirs 1975 |
| Coxsackie virus B5 | Lettuce, pieces | Spot inoculation, 0.1 ml inoculated onto each 16-mm disc. Virus grown in hep-2 cells, diluted in phosphate buffered saline. | Lettuce discs were stored in capped storage flasks with no moisture. | 4 | 2.0 | 7 d | ~1.9 | - | - | Konowalchuk and Speirs 1974 |
| Coxsackie virus B5 | Lettuce, pieces | Spot inoculation, 0.1ml inoculated onto each 16-mm disc. Virus grown in hep-2 cells, diluted in phosphate buffered saline. | Lettuce discs were stored in capped storage flasks with low moisture levels. | 4 | 2.0 | 7 d | ~1.6 | - | - | Konowalchuk and Speirs 1974 |
| Coxsackie virus B5 | Lettuce, pieces | Spot inoculation, 0.1 ml inoculated onto each 16-mm disc. Virus grown in hep-2 cells, diluted in phosphate buffered saline. | Lettuce discs were stored in capped storage flasks with high moisture levels. | 4 | 2.0 | 7 d | ~1.9 | PFU/sample | - | Konowalchuk and Speirs 1974 |
| Coxsackie virus B5 | Radish, whole root | 0.05 ml spot inoculated onto sample. Virus suspended in water. | Samples were left uncovered. | 4 | ~2.6 | 1 d 5 d |
~1.6 <0.6 |
PFU/sample | Presence of moisture improved survival. Survival significantly better in closed containers with high humidity. Presence of feces improved survival. | Konowalchuk and Speirs 1975 |
| Coxsackie virus B5 | Radish, whole root | 0.05 ml spot inoculated onto sample. Virus suspended in dilute feces (1%). | Samples were left uncovered. | 4 | ~2.6 | 1 d 5 d |
~1.8 ~1.3 |
PFU/sample | Presence of moisture improved survival. Survival significantly better in closed containers with high humidity. Presence of feces improved survival. | Konowalchuk and Speirs 1975 |
| Coxsackie virus B5 | Radish, whole root | 0.05 ml spot inoculated onto sample. Virus suspended in undiluted feces. | Samples were left uncovered. | 4 | ~2.6 | 1 d 5 d |
~2.0 ~1.7 |
PFU/sample | Presence of moisture improved survival. Survival significantly better in closed containers with high humidity. Presence of feces improved survival. | Konowalchuk and Speirs 1975 |
| Enteroviruses (5 strains) |
Lettuce | Virus suspended in saline, 1 ml inoculated per 100 g sample. | Samples were kept in 150-200 ml beakers. | 3.1 | Unknown | 11 d | - | TCD50/ml | 0.5 log decrease observed. | Bagdasaryan 1964 |
| Enteroviruses (5 strains) |
Tomato, whole | Virus suspended in saline, 1 ml inoculated per 100 g sample. | Samples were kept in 150-200 ml beakers. | 3-8 | Unknown | 15 d | - | TCD50/ml | 1 log decrease observed. | Bagdasaryan 1964 |
| Enteroviruses (5 strains) |
Tomato, whole | Virus suspended in saline, 1 ml inoculated per 100 g sample. | Samples were kept in 150-200 ml beakers. | 18-21 | Unknown | 15 d | - | TCD50/ml | 1 to 2.5 log decrease observed. | Bagdasaryan 1964 |
| Hepatitis A virus (strain hM 175) | Lettuce (pieces) | Inoculum contained 5% fetal bovine serum. | Samples were held in loosely covered petri dishes to allow air flow. | 4 22 |
7.3 7.3 |
12 d 12 d |
6.9 3.3 |
PFU/ml | - | Bidawid and others 2001 |
| Hepatitis A virus (strain hM 175) | Lettuce (pieces) | Inoculum contained 5% fetal bovine serum. | Samples held inside heat sealed plastic bag. | 4 22 |
7.3 7.3 |
12 d 12 d |
7.1 6.1 |
PFU/ml | - | Bidawid and others 2001 |
| Hepatitis A virus (strain hM 175) | Lettuce (pieces) | Inoculum contained 5% fetal bovine serum. | Samples held in heat sealed plastic bags containing 70% CO2 and 30% N2. | 4 22 |
7.3 7.3 |
12 d 12 d |
7.2 6.9 |
PFU/ml | - | Bidawid and others 2001 |
| Rotavirus SA-11 | Carrot, pieces | 0.1 ml spot inoculated onto sample. Virus grown on MA-104 cells. Virus suspended in Tris-buffered saline. | Samples stored in uncovered containers. | 4 25 |
4.5 4.5 |
25 d 15 d |
~1.2 ~1.0 |
PFU/ml | - | Badawy and others 1985 |
| Rotavirus SA-11 | Carrot, pieces | Immersion inoculation, 200 ml of 105 PFU/ml. Virus grown on MA-104 cells. Virus suspended in Tris-buffered saline. | Samples stored in uncovered containers. | 4 25 |
3.0 2.8 |
4 d 2 d |
<1.0 <1.0 |
PFU/ml | - | Badawy and others 1985 |
| Rotavirus SA-11 | Lettuce, pieces | 0.1 ml spot inoculated onto sample. Virus grown on MA-104 cells. Virus suspended in Tris-buffered saline. | Samples stored in uncovered containers. | 4 25 |
4.5 | 30 d 25 d |
2.5 1.1 |
PFU/ml | - | Badawy and others 1985 |
| Rotavirus SA-11 | Lettuce, pieces | Immersion inoculation, 200 ml of 105 PFU/ml. Virus grown on MA-104 cells. Virus suspended in Tris-buffered saline. | Samples stored in uncovered containers. | 4 25 |
4.5 | 25 d 15 d |
~1.2 ~1.2 |
PFU/ml | - | Badawy and others 1985 |
| Rotavirus SA-11 | Radish, whole root | 0.1 ml spot inoculated onto sample. Virus grown on MA-104 cells. Virus suspended in Tris-buffered saline. | Samples stored in covered containers. | 4 25 |
4.5 4.5 |
30 d 4 d |
~1.5 ~2.5 |
PFU/ml | - | Badawy and others 1985 |
| Rotavirus SA-11 | Radish, whole root | Immersion inoculation, 200 ml of 105 PFU/ml. Virus grown on MA-104 cells. Virus suspended in Tris-buffered saline. | Samples stored in uncovered containers. | 4 25 |
3.6 3.6 |
5 d 4 d |
~1.0 ~2.0 |
PFU/ml | - | Badawy and others 1985 |

