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Vibrio parahaemolyticus Risk Assessment - Appendix 10: Additional Information: What-if Scenarios

July 19, 2005

Table of Contents


Table A10-1.Predicted Mean Annual Illnesses with and without Mitigation
RegionSeasonPredicted Mean Number of Illnesses per Annuma
BaselineImmediate Refrigeration (~1 log10 Reduction)2-log10 Reduction4.5-log10 Reduction
Gulf Coast LouisianaSpring505 (36, 1.6x103)54 (3.0, 180)5.2 (0.35, 17)0.017 (1.1x10-3, 0.053)
Summer1,406 (109, 4.4x103)139 (7.6, 490)15 (1.1, 47)0.046 (3.5x10-3, 0.15)
Fall132 (6.4, 470)8.8 (0.34, 34)1.3 (0.060, 5.0)4.2x10-3 (2.0x10-4, 0.016)
Winter6.7 (0.16, 26)0.80 (0.04, 2.5)0.070 (1.7x10-3, 0.30)2.2x10-4 (3.9x10-6, 9.8x10-4)
Gulf Coast (Non-Louisiana)Spring193 (13, 630)29 (1.5, 98)2.0 (0.13, 6.3)6.2x10-3 (4.1x10-4, 0.020)
Summer299 (22, 980)42 (2.6, 140)3.1 (0.22, 10)9.7x10-3, (7.0x10-4, 0.032)
Fall51 (2.0, 180)7.7 (0.32, 28)0.51 (0.021, 1.8)1.6x10-3 (6.6x10-5, 5.8x10-3)
Winter2.9 (0.08, 11)0.72 (0.04, 2.3)0.028 (9.0x10-4, 0.11)8.8x10-5 (1.4x10-6, 3.5x10-4)
 Mid-AtlanticSpring4.4 (0.25, 15)0.53 (0.024, 2.0)0.045 (2.7x10-3, 0.16)1.4x10-4 (8.5x10-6, 5.1x10-4)
Summer6.9 (0.36, 25)0.83 (0.040, 3.2)0.070 (3.8x10-3, 0.26)2.2x10-4 (1.2x10-5, 8.0x10-4)
Fall3.8 (0.08, 17)0.64 (0.025, 2.4)0.037 (8.0x10-4, 0.16)1.2x10-4 (1.5x10-6, 5.2x10-4)
Winter0.012 (1.0x10-3, 0.041)0.01 (5.0x10-4, 0.037)1.1 x 10-4 (5.4x10-6, 4.1x10-4)3.4x10-7 (0.0, 2.3x10-6)
 Northeast AtlanticSpring3.0 (0.07, 12)0.33 (0.013, 1.2)0.031 (8.0x10-4, 0.13)9.7x10-5 (1.8x10-6, 3.9x10-4)
Summer14 (0.64, 53)1.7 (0.099, 6.2)0.14 (7.0x10-3, 0.53)4.4x10-4 (2.1x10-5, 1.6x10-3)
Fall1.7 (0.05, 6.8)0.55 (0.029, 1.8)0.018 (5.0x10-4, 0.073)5.6x10-5 (0.0, 2.3x10-4)
Winter0.027 (1.0x10-3, 0.083)0.024 (1.1x10-3, 0.0812.5 x 10-4 (1.1x10-5, 8.7x10-4)8.6x10-7 (0.0, 4.9x10-6)
 Pacific Northwest (Dredged)Spring0.42 (1.9x10-3, 1.5)0.051 (9.0x10-4, 0.16)4.7x10-3 (1.7x10-5, 1.7x10-2)1.5x10-5 (0.0, 5.1x10-5)
Summer3.9 (0.06, 16)0.37 (0.010, 1.5)0.044 (6.0x10-4, 0.20)1.4x10-4 (1.5x10-6, 6.5x10-4)
Fall0.024 (6.0x10-4, 0.085)8.1 x 10-3 (4.0x10-4, 0.031)2.1 x 10-4 (6.6x10-6, 7.4x14)6.7x10-7 (0.0, 4.2x10-6)
Winter6.0 x 10-4 (0.0, 2.2x 10-3)5.0 x 10-4 (1.9x10-5, 2.0x1035.5 x 10-6 (0.0, 2.2x10-5)1.5x10-8 (0.0, 0.0)
Pacific Northwest (Intertidal)bSpring18 (0.03, 82)10 (0.02, 50)0.22 (3.0x10-4, 1.1)7.0x10-4 (0.0, 3.5x10-3)
Summer173 (3.8, 750)96 (1.9, 420)2.1 (0.039, 9.4)6.8x10-3 (1.3x10-4, 0.03)
Fall1.0 (0.01, 4.3)0.49 (0.01, 1.7)8.5x10-3 (1.0x10-4, 0.029)2.7x10-5 (0.0, 1.1x10-4)
Winter3.3 x 10-3 (1.0x10-4, 0.013)3.2 x 10-3 (1.0x10-4, 0.013)3.4 x 10-5 (0.0, 1.4x10-4)9.2x10-8 (0.0, 0.0)

aValues in parentheses are the 5th percentile and 95th percentile of the uncertainty distribution. Values rounded to 2 significant digits. See Appendix 7 for actual illness numbers
b After intertidal exposure

Table A10-2. Predicted Mean Levels of Pathogenic Vibrio parahaemolyticus per gram in Oysters at Retail after Mitigation Treatments that Reduce Pathogen Levels
Predicted Mean Levels of Pathogenic Vibrio parahaemolyticus per grama
RegionSeasonNo MitigationImmediate Refrigeration (~1 log10 Reduction)2 log10 Reduction4.5 log10 Reduction
Gulf Coast (Louisiana)Spring39 (12, 88)4.2 (0.84, 12)0.39 (0.11, 0.89)1.2x10-3 (3.6×10-4, 2.8×10-3)
Summer100 (37, 220)10 (2.3, 29)1.0 (0.36, 2.2)3.3×10-3 (1.2×10-3, 6.8×10-3)
Fall10 (1.8, 25)0.65 (0.09, 2.1)0.10 (0.016, 0.24)3.1×10-4×(5.0×10-5,×7.7×10-4
Winter0.48 (0.04, 1.6)0.059 (0.013, 0.16)5.0×10-3 (3.9×10-4, 0.018)1.6×10-5 (9.9×10-7, 5.7×10-5)
Gulf Coast (Non-Louisiana)Spring28 (7.6, 65)4.2 (0.82, 12)0.28 (0.075, 0.65)8.8×10-4 (2.4×10-4, 2.0×10-3)
Summer73 (24, 160)10 (2.4, 28)0.73 (0.24, 1.6)2.3×10-3 (7.5×10-4, 5.0×10-3)
Fall4.4 (0.64, 12)0.65 (0.09, 2.1)0.043 (5.6×10-3, 0.12)1.4×10-4 (1.8×10-5, 4.0×10-4)
Winter0.23 (0.026, 0.80)0.060 (0.014, 0.17)2.3×10-3 (2.7×10-4, 7.5×10-3)7.2×10-6 (5.0×10-7, 2.4×10-5)
Mid-Atlantic Spring7.3 (1.7, 18)0.88 (0.14, 2.7)0.073 (0.015, 0.17)2.3×10-4 (5.1×10-5, 5.4×10-4)
Summer21 (3.8, 54)2.6 (0.46, 7.6)0.21 (0.036, 0.54)6.7×10-4 (1.1×10-4, 1.7×10-3)
Fall0.54 (0.035, 2.0)0.09 (0.014, 0.32)5.1×10-3 (3.3×10-4, 0.019)1.6×10-5 (9.7×10-7, 6.0×10-5)
Winter2.4×10-3 (4.0×10-4, 5.8×10-3)2.3×10-3 (4.0×10-4, 5.4×10-3)2.4×10-5 (3.5×10-6, 6.1×10-5)7.5×10-8 (0.0, 5.0×10-7)
Northeast AtlanticSpring0.88 (0.064, 3.0)0.097 (0.015, 0.29)8.9×10-3 (6.2×10-4, 0.032)2.8×10-5 (1.5×10-6, 1.0×10-4)
Summer4.3 (0.68, 12)0.52 (0.11, 1.5)0.042 (6.8×10-3, 0.11)1.3×10-4 (2.1×10-5, 3.7×10-4)
Fall0.088 (0.012, 0.29)0.030 (7.1×10-3, 0.08)9.9×10-4 (1.2×10-4, 3.4×10-3)3.2×10-6 (0.0, 1.2×10-5)
Winter2.5×10-3 (4.0×10-4, 6.3×10-3)2.3×10-3 (4.2×10-4, 5.9×10-3)2.4×10-5 (3.5×10-6, 6.1×10-5)8.3×10-8 (0.0, 5.0×10-7)
Pacific Northwest (Dredged)bSpring0.22 (0.002, 0.87)0.022 (1.1×10-3, 0.076)2.1×10-3 (2.0×10-5, 9.2×10-3)6.9×10-6 (0.0, 3.0×10-5)
Summer2.3 (0.10, 11)0.20 (0.02, 0.68)0.023 (9.9×10-4, 0.097)7.4×10-5 (3.0×10-6, 3.1×10-4
Fall5.8×10-3 (6.0×10-4, 0.018)1.9×10-3 (4.0×10-4, 5.0×10-3)4.9×10-5 (5.9×10-6, 1.4×10-7)1.7×10-7 (0.0, 9.9×10-7)
Winter1.9×10-4 (2×10-5, 6.1×10-4)1.7×10-4 (1.9×10-5, 5.6×10-4)1.9×10-6 (0.00, 6.4×10-6)5.5×10-9 (0.0, 0.0)
Pacific Northwest (Intertidal)cSpring3.7 (0.014, 19)1.9 (9.2×10-3, 9.7)0.035 (1.2×10-4, 0.20)1.1×10-4 (3.9×10-7, 6.3×10-4)
Summer38 (2.0, 140)20 (0.95, 84)0.38 (0.018, 1.5)1.2×10-3 (5.6×10-5, 4.9×10-3)
Fall0.086 (3.0×10-3, 0.30)0.038 (2.2×10-3, 0.13)6.9×10-4 (3.0×10-5, 2.3×10-3)2.2×10-6 (8.7×10-8, 7.3×10-6)
Winter4.0×10-4 (3.0×10-5, 1.4×10-3)3.7×10-4 (3.0×10-5, 1.3×10-3)4.0×10-6 (3.4×10-7, 1.4×10-5)1.3×10-8 (1.1×10-9, 4.3×10-8)

aValues in parentheses are the 5th percentile and 95th percentile of the uncertainty distribution. Values rounded to 2 significant digits. See Appendix 7 for actual predicted levels.

Table A10-3. Predicted Mean Numbers of Pathogenic Vibrio parahaemolyticus per Serving of Oysters after Mitigation Treatments that Reduce Pathogen Levels
RegionSeasonAt HarvestaNo MitigationbImmediate Refrigeration2 log10 reductionb4.5 log10 reductionb
Gulf Coast (Louisiana)Spring3207.9×103 (2.3×103, 1.8×104)840 (170, 2.4×103)78 (22, 180)0.25 (0.072, 0.57)
Summer7202.1×104 (7.5×103, 4.4×104)2.0×103 (470, 5.8×103)210 (73, 440)0.66 (0.23, 1.4)
Fall802.0×103 (320, 5.1×103)130 (18, 420)20 (3.2, 49)0.06 (0.01, 0.16)
Winter1898 (8.1, 330)12 (2.6, 33)1.0 (0.078, 3.6)3.2×10-3 (2.0×10-4, 0.012)
Gulf Coast (Non-Louisiana)Spring3205.6×103 (1.5×103, 1.3×104)850 (170, 2.4×103)56 (15, 130)0.18 (0.048, 0.41)
Summer7201.5×104 (4.9×103, 3.2×104)2.0×103 (480, 5.7×103)150 (49, 320)0.47 (0.15, 1.0)
Fall80880 (110, 2.5×103)130 (19, 430)8.6 (1.1, 25)0.027 (3.7×10-3, 0.08)
Winter1847 (5.1, 160)12 (2.7, 35)0.46 (0.054, 1.5)1.5×10-3 (1.0×10-4, 4.9×10-3)
Mid-AtlanticSpring661.5×103 (330, 3.5×103)180 (27, 550)15 (3.1, 35)0.047 (0.01, 0.11)
Summer2604.3×103 (750, 1.1×104)520 (92, 1.5×103)43 (7.3, 110)0.14 (0.023, 0.34)
Fall18110 (7.1, 410)18 (2.8, 64)1.0 (0.07, 3.9)3.2×10-3 (2.0×10-4, 0.012)
Winter1.20.48 (0.09, 1.2)0.46 (0.08, 1.1)4.9×10-3 (7.0×10-4, 0.012)1.5×10-5 (0.0, 1.0×10-4
 Northeast AtlanticSpring14180 (12, 620)20 (2.9, 59)1.8 (0.13, 6.5)5.7×10-3 (3.0×10-4, 0.02)
Summer78860 (130, 2.5×103)100 (22, 300)8.5 (1.4, 23)0.027 (4.2×10-3, 0.074)
Fall1217 (2.4, 57)6.1 (1.4, 16)0.20 (0.024, 0.68)6.4×10-4 (0.0, 2.4×10-3)
Winter1.20.5 (0.09, 1.2)0.47 (0.085, 1.2)4.9×10-3 (7.0×10-4, 0.012)1.7×10-5 (0.0, 1.0×10-4)
Pacific Northwest (Dredged)Spring443 (0. 4, 160)4.5 (0.23, 15)0.43 (4.1×10-3, 1.9)1.4×10-3 (0.0, 6.0×10-3)
Summer24460 (21, 2.1×103)40 (4.7, 140)4.7 (0. 2, 19)0.015 (6.0v10-4, 0.062)
Fall0.681.2 (0.12, 3.6)0.39 (0.081, 1.0)9.9×10-3 (1.2×10-3, 0.03)3.3×10-5 (0.0, 2.0×10-4)
Winter0.080.04 (0.00, 0.12)0.034 (3.9×10-3, 0.11)3.8×10-4 (0.0, 1.3×10-3)1.1×10-6 (0.0, 0.0)
Pacific Northwest (Intertidal)Spring280740 (2.6, 3.7×104)380 (1.9, 2.0×103)7.1 (0.025, 40)0.022 (8.0×10-5, 0.13)
Summer3.0×1037.5×103 (370, 3.0×104)4.1×103 (190, 1.7×104)77 (3.6, 310)0.24 (0.011, 0.98)
Fall1017 (0.50, 74)7.7 (0.45, 27)0.14 (5.6×10-3, 0.47)4.4×10-4 (2.0×10-5, 1.5×10-3)
Winter0.180.08 (0.01, 0.28)0.075 (6.6×10-3, 0.26)8.0×10-4 (7.0×10-5, 2.8×10-3)2.5×10-6 (2.2×10-7, 8.7×10-6)

aMean number of pathogenic V. parahaemolyticus consumed per serving (average over variabilities and uncertainties)
bValues in parentheses are the 5th percentile and 95th percentile of the uncertainty distribution. Values rounded to 2 significant digits. See Appendix 7 for actual predicted levels.

Impact of overnight submersion of oysters during intertidal harvesting on the predicted risk of illness

 

Table A10-4. Effect of Overnight Submersion of Oysters during Intertidal Harvest on Predicted Risk in the Pacific Northwest Harvest Region
Type of HarvestSeasonMean Risk per Serving
Baseline Intertidal HarvestWinter1.7×10-9
Spring1.3×10-5
Summer1.4×10-4
Fall3.9×10-7
Overnight Submersion of Intertidal HarvestaWinter8.1×10-10
Spring8.7×10-7
Summer1.0×10-5
Fall2.7×10-8

aThis assumes levels of V. parahaemolyticus in oysters after submersion overnight are similar to dredged.

Predicted Effects of Maximum Time-to-Refrigeration on Illness Using Ice (Rapid Refrigeration) or Conventional Refrigeration (Air- Circulated)

Tables A10-5 to A10-8 show the impact of rapid cooling with ice on predicted reduction in levels of total V. parahaemolyticus at-retail compared with the baseline levels. Figures A10-1 to A10-6 show predicted effects on illness of maximum time-to-refrigeration of oyster shellstock with conventional refrigeration (i.e., up to 10 hours to reach no-growth temperatures) for each season and region. Figures A10-7 -A10-12 show predicted effects on illness of maximum time-to-refrigeration of oyster shellstock with rapid cooling on ice (i.e., 1 hour to reach no-growth temperatures) for each season and region. Figures A10-13 to A10-18 compare the predicted effects between conventional refrigeration and rapid cooling for the summer harvest of all 6 harvesting regions. As mentioned in Chapter VII of the technical document, predicted reductions for regions and seasons with lower air temperatures are less dramatic than those with higher air temperatures as shown in the figures below.

Effect of Limiting Time to Refrigeration followed by rapid cooling (icing) on the mean and 90th %-tile of total Vp/g at retail (point of consumption)

 

Table A10-5. Best estimate of the Mean total Vp/g at retail for all region/seasons
RegionSeasonTime-to-Refrigeration
1 hr2 hr3 hr4 hrbaseline
Gulf Louisianawinter25a313744290
spring9701.6×1032.5×1033.8×1032.3×104
summer2.3×1033.8×1036.1×1039.1×1036.0×104
fall1702704006105.7×103
Gulf non-Louisianawinter26313642140
spring9701.6×1032.4×1033.4×1031.6×104
summer2.3×1033.8×1035.8×1038.3×1034.2×104
fall1762653835282.5×103
 Northeast Atlanticwinter1.31.41.41.41.5
spring284056.077510
summer1652303104102.5×103
fall1416182052
Mid-Atlanticwinter1.31.31.31.31.4
spring1903205007504.2×103
summer6801.0×1031.5×1032.1×1031.2×104
fall324356773300
Pacific Northwest (dredged)winter0.0070.0070.0070.0070.008
spring0.540.741.01.39.1
summer4.16.18.712100
fall0.0700.0800.0910.1020.230
 Pacific Northwest (intertidal)winter0.0150.0150.0150.0150.017
spring47546063150
summer5206006607001.7×103
fall1.61.61.81.93.9

aLevels of V. parahaemolyticus at-retail after cooling at various time intervals after harvest; values are rounded to 2 significant digits

Table A10-6. Best estimate of the 90th percentile of the distribution of total Vp/g at retail for all region seasons
RegionSeasonTime-to-Refrigeration
1 hr2 hr3 hr4 hrBaseline
Gulf Louisianawinter35a404551120
spring1.1×1031.9×1032.9×1034.4×1034.6×104
summer3.8×1036.8×1031.1×1041.8×1042×105
fall1602102803702.8×103
Gulf non-Louisianawinter3539444884
spring1.2×1031.9×1032.8×1033.9×1032.6×104
summer3.8×1036.7×1031.1×1041.6×1041.2×105
fall1602102703301.0×103
Northeast Atlanticwinter2.32.32.32.32.3
spring27333945100
summer2403304405602.5×103
fall1819212228
Mid-Atlanticwinter2.12.12.12.12.2
spring1401902603301.3×103
summer9901.5×1032.2×1033.1×1032.2×104
fall2327293148
Pacific Northwest (dredged)winter0.0150.0150.0160.0160.017
spring0.700.861.01.22.6
summer5.77.69.81240
fall0.0980.100.110.120.15
Pacific Northwest (intertidal)winter0.0280.0280.0280.0280.030
spring1113141527
summer240280310330800
fall0.400.400.410.420.51

a aLevels of V. parahaemolyticus at-retail after cooling at various time intervals after harvest; values are rounded to 2 significant digits

Effect of Limiting Time to Refrigeration followed by conventional cooling on the mean and 90th %-tile of total Vp/g at retail (point of consumption)

 

Table A10-7. Best estimate of the Mean total Vp/g at retail for all region/seasons
RegionSeasonTime-to-Refrigeration
1 hr2 hr3 hr4 hrBaseline
Gulf Louisianawinter43a557089290
spring4.0×1036.2×1038.9×1031.2×1042.2×104
summer9.8×1031.5×1042.3×1043.1×1046.0×104
fall6209501.4×1031.9×1035.7×103
Gulf non-Louisianawinter43556882140
spring4.0×1036.1×1038.6×1031.1×1041.6×104
summer9.8×1031.5×1042.2×1042.8×1044.2×104
fall6209301.3×1031.7×1032.5×103
 Northeast Atlanticwinter1.41.41.41.41.5
spring90140200270510
summer4606709301.2×1032.5×103
fall2125303552
Mid-Atlanticwinter1.31.31.41.41.4
spring8601.3×1031.9×1032.5×1034.2×103
summer2.4×1033.7×1035.2×1036.9×1031.2×104
fall78110150190310
Pacific Northwest (dredged)winter0.0070.0080.0080.0080.008
spring1.52.23.14.39.1
summer14213244100
fall0.100.120.150.170.23
Pacific Northwest (intertidal)winter0.0160.0160.0170.0170.017
spring110130140150150
summer1.2×1031.4×1031.5×1031.6×1031.7×103
fall3.63.64.04.23.9

aLevels of V. parahaemolyticus at-retail after cooling at various time intervals after harvest; values are rounded to 2 significant digits

Table A10-8. Best estimate of the 90th percentile of the distribution of total Vp/g at retail for all region seasons
RegionSeasonTime-to-Refrigeration
1 hr2 hr3 hr4 hrbaseline
Gulf Louisianawinter48a566573120
spring4.3×1037.3×1031.2×1041.8×1044.7×104
summer1.9×1043.4×1045.5×1048.3×1042.0×105
fall3404706508802.8×103
Gulf non-Louisianawinter4856637084
spring4.3×1037.2×1031.1×1041.6×1042.6×104
summer1.9×1043.3×1045.3×1047.5×1041.3×105
fall3404706107601.0×103
 Northeast Atlanticwinter2.32.32.32.32.3
spring45576880100
summer5908401.1×1031.5×1032.5×103
fall2223252628
Mid-Atlanticwinter2.12.22.22.22.2
spring3304806508301.3×103
summer3.3×1035.3×1037.9×1031.1×1042.2×104
fall3135394248
Pacific Northwest (dredged)winter0.0160.0160.0160.0160.017
spring1.21.41.72.02.6
summer1217222740
fall0.120.130.130.140.15
Pacific Northwest (intertidal)winter0.0290.0290.0290.0290.030
spring2124262727
summer550650730780800
fall0.490.490.500.510.51

aLevels of V. parahaemolyticus at-retail after cooling at various time intervals after harvest; values are rounded to 2 significant digits

Effect of Limiting Time to Refrigeration (Conventional Cooling and Rapid cooling on Ice) on Average Levels of Total Vp/g at Retail (Point of Consumption)

Figure A10-1. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Coast, Non- Louisiana Harvest)

Figure A10-1. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Coast, Non- Louisiana Harvest).

Figure A10-2. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Coast, Louisiana Harvest)

Figure A10-2. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Coast, Louisiana Harvest).

Figure A10-3. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Northeast Atlantic Harvest)

Figure A10-3. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Northeast Atlantic Harvest).

Figure A10-4. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Mid-Atlantic Harvest)

Figure A10-4. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Mid-Atlantic Harvest).

Figure A10-5. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Dredged Harvest)

Figure A10-5. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Dredged Harvest).

Figure A10-6. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Intertidal Harvest)

Figure A10-6. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Intertidal Harvest).

Figure A10-7. Predicted Effect of Maximum Time to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Gulf Coast, Non-Louisiana Harvest)

Figure A10-7. Predicted Effect of Maximum Time to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Gulf Coast, Non-Louisiana Harvest).

Figure A10-8. Predicted Effect of Maximum Time to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Gulf Coast, Louisiana Harvest)

Figure A10-8. Predicted Effect of Maximum Time to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Gulf Coast, Louisiana Harvest).

Figure A10-9. Predicted Effect of Maximum Time to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Northeast Atlantic Harvest)

Figure A10-9. Predicted Effect of Maximum Time to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Northeast Atlantic Harvest).

Figure A10-10. Predicted Effect of Maximum Time to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Mid-Atlantic Harvest)

Figure A10-10. Predicted Effect of Maximum Time to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Mid-Atlantic Harvest).

Figure A10-11. Predicted Effect of Maximum Time to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Pacific Northwest Dredged Harvest)

Figure A10-11. Predicted Effect of Maximum Time to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Pacific Northwest Dredged Harvest).

Figure A10-12. Predicted Effect of Maximum Time to Refrigeration with Rapid (on (on ice) Cooling of Oyster Shellstock (Pacific Northwest Intertidal Harvest)

Figure A10-12. Predicted Effect of Maximum Time to Refrigeration with Rapid (on (on ice) Cooling of Oyster Shellstock (Pacific Northwest Intertidal Harvest).

 

 

Figures on Effect of Limiting Time to Refrigeration (conventional cooling and rapid cooling) on the 90th percentile of the distribution of total V. parahaemolyticus/g at retail (point of consumption)

Figure A10-13. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Non- Coast, Louisiana Harvest)

Figure A10-13. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Non- Coast, Louisiana Harvest).

Figure A10-14. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Coast Louisiana Harvest)

Figure A10-14. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Coast Louisiana Harvest).

Figure A10-15. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Northeast Atlantic Harvest)

Figure A10-15. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Northeast Atlantic Harvest).

Figure A10-16. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Mid-Atlantic Harvest)

Figure A10-16. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Mid-Atlantic Harvest).

Figure A10-17. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Dredged Harvest)

Figure A10-17. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Dredged Harvest).

Figure A10-18. Predicted Effect of Maximum Time-to-Refrigeration with Rapid Conventional (Air Circulated) Cooling of Oyster Shellstock (Pacific Northwest Intertidal Harvest)

Figure A10-18. Predicted Effect of Maximum Time-to-Refrigeration with Rapid Conventional (Air Circulated) Cooling of Oyster Shellstock (Pacific Northwest Intertidal Harvest).

Figure A10-19. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Gulf Coast, Non-Louisiana Harvest)

Figure A10-19. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Gulf Coast, Non-Louisiana Harvest).

Figure A10-20. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Gulf Coast, Louisiana Harvest)

Figure A10-20. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Gulf Coast, Louisiana Harvest).

Figure A10-21. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Northeast Atlantic Harvest)

Figure A10-21. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Northeast Atlantic Harvest).

Figure A10-22. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Mid-Atlantic Harvest)

Figure A10-22. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Mid-Atlantic Harvest).

Figure A10-23. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Pacific Northwest Dredged Harvest)

Figure A10-23. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Pacific Northwest Dredged Harvest).

Figure A10-24. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Pacific Northwest Intertidal Harvest)

Figure A10-24. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Pacific Northwest Intertidal Harvest).

Table A10-9 shows the impact of rapid cooling on ice on reducing the levels of V. parahaemolyticus with the corresponding decrease in risk per serving.

Table A10-9. Percentage Reduction of Vibrio parahaemolyticus /g versus Risk After Immediate Refrigeration with Icing for the Gulf Coast (Louisiana) Summer Harvest
Time-to-Refrigeration (h)% reduction of total Vp/g% reduction of risk per serving
196.2%96.5%
293.6%94.1%
389.9%90.7%
484.8%85.9%



 

Figures on Effect of Limiting Time to Refrigeration (conventional cooling and rapid cooling) on the Reduction of Risk Per Serving

Figure A10-25. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Coast, Louisiana Harvest)

Figure A10-25. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Coast, Louisiana Harvest).

Figure A10-26. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Northeast Atlantic Harvest)

Figure A10-26. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Northeast Atlantic Harvest).

Figure A10-27. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Mid-Atlantic Harvest)

Figure A10-27. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Mid-Atlantic Harvest).

Figure A10-28. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Dredged Harvest)

Figure A10-28. Predicted Effect of Maximum Time-to-Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Dredged Harvest).

Figure A10-29. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Intertidal Harvest)

Figure A10-29. Predicted Effect of Maximum Time to Refrigeration with Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Intertidal Harvest).

Figure A10-30. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Gulf Coast, Non-Louisiana Harvest)

Figure A10-30. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Gulf Coast, Non-Louisiana Harvest).

Figure A10-31. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Gulf Coast, Louisiana Harvest)

Figure A10-31. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Gulf Coast, Louisiana Harvest).

Figure A10-32. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Northeast Atlantic Harvest.)

Figure A10-32. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Northeast Atlantic Harvest.)

Figure A10-33. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Mid-Atlantic Harvest.)

Figure A10-33. Predicted Effect of Maximum Time-to-Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Mid-Atlantic Harvest.)

Figure A10-34. Predicted Effect of Maximum Time to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Pacific Northwest Dredged Harvest)


 

Figure A10-34. Predicted Effect of Maximum Time to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Pacific Northwest Dredged Harvest)

Figure A10-35. Predicted Effect of Maximum-Time-to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Pacific Northwest Intertidal Harvest)

Figure A10-35. Predicted Effect of Maximum-Time-to Refrigeration with Rapid (on ice) Cooling of Oyster Shellstock (Pacific Northwest Intertidal Harvest).

 

Comparison on Impact of Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock on Reduction of Mean Risk Per Serving

Figure A10-36. Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Coast, Non-Louisiana Summer Harvest)

Figure A10-36. Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Coast, Non-Louisiana Summer Harvest).

Figure A10-37. Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Coast, Louisiana Summer Harvest)

Figure A10-37. Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock (Gulf Coast, Louisiana Summer Harvest).

Figure A10-38. Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock (Northeast Atlantic Summer Harvest)

Figure A10-38. Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock (Northeast Atlantic Summer Harvest).

Figure A10-39. Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock (Mid-Atlantic Summer Harvest)

Figure A10-39. Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock (Mid-Atlantic Summer Harvest).

Figure A10-40. Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Summer Dredged Harvest)

Figure A10-40. Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Summer Dredged Harvest).

Figure A10-41. Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Summer Intertidal Harvest)

Figure A10-41. Rapid (on ice) Cooling versus Conventional (Air-Circulated) Cooling of Oyster Shellstock (Pacific Northwest Summer Intertidal Harvest).

Effect of Deviation from Compliance on "At-Harvest" Guidance Levels Scenarios

The impact on illness and effect on harvest at different V. parahaemolyticus guidance levels for "at harvest" control was evaluated in Chapter VI of the technical document. It was recognized that deviation from compliance with these harvest guidance levels can occur in any region and season. The Louisiana Gulf Coast Summer harvest was selected as the region/season combination for illustrative example because the Gulf has the highest summer temperatures and Louisiana has the longest potential time for having oysters out of the water.

Selected levels of deviation from compliance (ranging from 0 to 50%) with different guidance levels (ranging from 100 to 100,000/g) were evaluated. The analyses were accomplished by altering the baseline model to represent the potential effect of the different levels of deviation from compliance. In other words, the impact of the different guidance levels determined in the above evaluation of the 10,000 V. parahaemolyticus/g was used as the 100% compliance (or 0% deviation from compliance) control and the outcome when 0, 10, 30, or 50% of the oysters containing more V. parahaemolyticus/g than the guidance level in question were allowed to reach the consumer. As seen in Table A10-10, the lower the standard level in question, the greater the impact of deviation from compliance on both percentage illnesses averted and loss of oyster harvest. At an "at-harvest" guidance level of 100 V. parahaemolyticus/g, a 30% deviation from compliance only reduces illness by 82% as compared to the 98% reduction predicted if 100% compliance were met.

At 10,000 and 100,000 V. parahaemolyticus/g the differences in illness reduction between 100% compliance and 70% compliance are not large. Therefore, as demonstrated in Figures A10-19 to A10-23, as the level of the microbiological criterion increases, the impact of compliance is less important. Conversely, strict microbiological criteria must be matched with a high level of compliance if they are to be effective.

Table A10-10. Effect of Compliance Levels on the Effectiveness of Controlling Total Vibrio parahaemolyticus in Oysters at the Time of Harvest for Gulf Coast Louisiana Summer
Total Vp/g At Time of HarvestaCompliance LevelbReduction in Mean Risk per Serving (%)Harvest Diverted (%)cIllness Averted (%)d
100/g50%47.7%33.0%64.9%
70%66.7%46.2%82.1%
90%85.7%59.4%94.2%
100%95.3%66.0%98.4%
1000/g50%29.6%10.6%37.3%
70%41.3%14.9%50.4%
90%53.0%19.1%62.6%
100%58.9%21.3%68.2%
5000/g50%11.4%2.8%14.4%
70%15.9%3.9%19.9%
90%20.4%5.1%25.4%
100%22.7%5.6%28.1%
10,000/g50%6.4%1.4%8.2%
70%8.9%2.0%11.4%
90%11.4%2.6%14.6%
100%12.7%2.9%16.2%
100,000/g50%0.57%0.12%0.79%
70%0.77%0.17%1.11%
90%0.99%0.22%1.43%
100%1.10%0.25%1.58%

a Assumes that the level of Vibrio parahaemolyticus (Vp) is known in oysters at the time of harvest.
b The compliance level is the percentage oyster harvest, which is removed from the raw oyster consumption market; this percentage is assumed to have the same distribution of Vp/g as under the baseline (no mitigation) scenario.
c Refers to the harvest that would need to be diverted from the "raw market".
d Assuming that the volume of product available for raw consumption is impacted (i.e., reduced) according to the estimate of the % of harvest lost from the raw market.

Figure A10-42. Percentage of Illnesses Averted

Figure A10-42. Percentage of Illnesses Averted

Figure A10-43. Percentage Reduction in Mean Risk per Serving

Figure A10-43. Percentage Reduction in Mean Risk per Serving

Figure A10-44. Percentage of Oyster Harvest Diverted from the "Raw Market" or Subjected to Preventive Controls

Figure A10-44. Percentage of Oyster Harvest Diverted from the "Raw Market" or Subjected to Preventive Controls.

Figure A10-45. Percentage Reduction in Mean Risk per Serving versus Percentage of Harvest Diverted from the "Raw Market" or Subjected to Preventive Controls

Figure A10-45. Percentage Reduction in Mean Risk per Serving versus Percentage of Harvest Diverted from the "Raw Market" or Subjected to Preventive Controls

Figure A10-46. Percentage of Illnesses Averted versus Percentage of Harvest Diverted From the "Raw Market" or Subjected to Preventive Controls


 

Figure A10-46. Percentage of Illnesses Averted versus Percentage of Harvest Diverted From the "Raw Market" or Subjected to Preventive Controls.

 

Effect of Deviation from Compliance on "At-Retail" Guidance Levels Scenarios

The impact of deviation from compliance at retail was evaluated in a similar manner to that at harvest. Selected levels of deviation from compliance (ranging from 0 to 50%) with different guidance levels (ranging from 100 to 100,000/g) was evaluated. Impact of deviation from compliance at retail is much higher at the higher standard levels at retail compared to that of at-harvest deviation from compliance (compare Tables A10-4 and A10-5). As seen in Table A10-5, like deviation from compliance at harvest, the lower the standard level in question, the greater the impact of deviation from compliance on loss of oyster harvest to the raw market. However, in the case of illness, deviation from compliance at retail appears to have a greater impact when the guidance level is high, even though a compliance rate of 100% does not result in 100% reduction in illness. At a retail guidance level of 100 V. parahaemolyticus/g, a 30% deviation from compliance reduces illness by approximately 90% as compared to the ~100% reduction predicted if 100% compliance were met. A rate of 50% deviation from compliance would result in approximately 74% reduction in illness versus the ~100% predicted if 100% compliance were met. If the guidance level was increased to 5, 000 V. parahaemolyticus/g, 50% compliance results in a larger decrease in the reduction of illness (approximately 63%) compared to ~100% predicted if there was 100% compliance.

At 10,000 and 100,000 V. parahaemolyticus/g the differences in illness reduction between 100% compliance and 70% compliance are larger than at 100 or 1,000. Therefore, as demonstrated in Figures A10-24 to A10-27, as the level of the microbiological criterion increases, the impact of compliance is more important on illness. Conversely, strict microbiological criteria must be matched with a high level of compliance if they are to be effective.

A deviation from compliance rate of 30% would substantially impact the reduction in risk of illness per serving (Table A10-11) for the higher guidance criteria. It is interesting to note that like at-harvest guidance, at 50% deviation from compliance of the lower guidance levels (100 and 1,000 V. parahaemolyticus/g), although the harvest is reduced by half of that at 100% compliance, reduction in illness is not equivalent. At the higher guidance levels, reduction in illness at 50% deviation from compliance is closer to half that at 100% compliance.

Effect of Deviation from Compliance on "At-Cooldown" Guidance Levels Scenarios

Table A10-11. Effect of Compliance Levels on the Effectiveness of Controlling Total Vibrio parahaemolyticus in Oysters at Retail for Gulf Coast Louisiana Summer
Total Vp/g At-RetailaCompliance LevelbReduction in Mean Risk per Serving (%)Harvest Diverted (%)cIllness Averted (%)d
100/g50%50.0%49.0%74.5%
70%70.1%68.6%90.6%
90%90.0%88.2%98.8%
100%~100%98.0%~100%
1000/g50%50.0%43.5%71.7%
70%70.0%60.9%88.3%
90%90.0%78.3%97.8%
100%~100%87.0%~100%
5000/g50%49.8%34.5%67.1%
70%69.9%48.3%84.4%
90%89.7%62.1%96.1%
100%99.6%69.0%99.9%
10,000/g50%49.5%29.7%64.6%
70%69.4%41.5%82.1%
90%89.2%53.4%96.0%
100%99.0%59.399.7%
100,000/g50%45.3%13.9%53.4%
70%63.4%19.4%71.2%
90%781.6%25.0%86.9%
100%90.6%27.8%94.1%

a Assumes that the level of Vibrio parahaemolyticus (Vp) is known in oysters at the time of harvest.
b The % of non-compliant oyster harvest which is removed from the raw oyster consumption market; non-compliant oyster harvest consumed raw is assumed to have the same distribution of Vp/g as (above the compliance level) as under the baseline (no mitigation) scenario.
c Refers to the harvest that would need to be diverted from the "raw market".
d Assuming that the volume of product available for raw consumption is impacted (i.e., reduced) according to the estimate of the % of harvest lost.

Figure A10-47. Percentage of Illnesses Averted

Figure A10-47. Percentage of Illnesses Averted

Figure A10-48. Percentage Reduction in Mean Risk per Serving

Figure A10-48. Percentage Reduction in Mean Risk per Serving.

Figure A10-49. Percentage of Oyster Harvest Lost to Raw Consumption Market

Figure A10-49. Percentage of Oyster Harvest Lost to Raw Consumption Market

Figure A10-50. Percentage of Illnesses Averted versus Percentage of Harvest Lost to Raw Consumption Market

Figure A10-50. Percentage of Illnesses Averted versus Percentage of Harvest Lost to Raw Consumption Market

 

Effect of Deviation from Compliance on "At-Retail" Guidance Levels Scenarios

 

Table A10-12. Effect of Compliance Levels on the Effectiveness of Controlling Total Vibrio parahaemolyticus in Oysters at Retail for Gulf Coast Louisiana Summer
Total Vp/g At-RetailaCompliance LevelbReduction in Mean Risk per Serving (%)Harvest Diverted (%)cIllness Averted (%)d
100/g50%50.0%47.0%73.5%
70%70.0%65.8%89.7%
90%90.0%84.6%98.5%
100%~100%94.0%~100%
1000/g50%49.7%37.4%68.6%
70%69.8%52.3%85.6%
90%89.9%67.2%96.7%
100%99.8%74.7%~100%
5000/g50%49.3%26.4%62.8%
70%69.1%36.9%80.6%
90%88.8%47.5%94.2%
100%98.6%52.8%99.5%
10,000/g50%48.4%21.5%59.8%
70%68.1%30.1%77.9%
90%87.5%38.7%92.6%
100%97.2%43.0%98.6%
100,000/g50%39.7%8.3%45.6%
70%55.4%11.7%62.0%
90%71.4%15.0%77.2%
100%79.4%16.7%84.4%

a Assumes that the level of Vibrio parahaemolyticus (Vp) is known in oysters at the time of harvest.
b The compliance level is the percentage oyster harvest, which is removed from the raw oyster consumption market or subjected to preventive controls; this percentage is assumed to have the same distribution of Vp/g as under the baseline (no mitigation) scenario.
c Refers to the harvest that would need to be diverted from the "raw market" or subjected to preventive controls.
d Assuming that the volume of product available for raw consumption is impacted (i.e., reduced) according to the estimate of the % of harvest lost from the raw market or subjected to preventive controls.

In summary, as the levels increase, the percentage compliance for the at-harvest guidance is not as important in part because fewer numbers of illnesses are prevented at the higher guidance levels. When these same guidance levels are applied at-retail, however, a high percentage of illnesses is prevented, even when compliance is not 100%. For example, to obtain a 60% reduction in illness rates (assuming 50% compliance), the guidance level would need to be 100 at-harvest but at-retail could be as high as 10,000 V. parahaemolyticus/g.


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