List of Terms: T
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> Thermometer(see Food Thermometer)
A poison that is produced by microorganisms, carried by fish, or released by plants.
Food Safety Implication: As pathogens multiply, they can give off harmful toxins or become infectious. If pathogens get into our food and multiply, people can get sick when they eat the food. To prevent toxins from developing in food, consumers should not hold food in the danger zone, the temperature range in which most bacteria can grow. This range is usually below 40° F (4° C). Some pathogenic bacteria grow at 32° F (0° C) or above 140° F (60° C). Toxins can develop in foods sitting out at room temperature for more than 2 hours. When in doubt, throw the food out.
Some Examples of Toxins in Food:
- Mycotoxins - produced by fungi (molds) in food and animal feed (see Mycotoxins).
- Staphylococcal Toxin - produced by Staphylococcus aureus. This toxin is the result of improperly-refrigerated foods and is a food-handling problem.
Some Examples of Diseases Caused by Toxins:
- Botulism - caused by the toxin from Clostridium botulinum. The toxin produced by Clostridium botulinum is one of the most potent and deadly toxins known to humankind. (See Canning and Clostridium botulinum.)
- Scombroid Poisoning - caused by histamine in conjunction with other amino acids produced by bacterial decomposition in some improperly refrigerated fish, such as mackerel and tuna (especially the scombroid species).
Sources: Raw or undercooked pork, lamb, or venison and cat, rat, rodent, or bird feces.
Incubation: Approximately 1 to 3 weeks.
Symptoms: Swollen glands, fever, and muscle aches. People in the at-risk groups may experience more severe symptoms.
Duration: A few weeks.
A term used in epidemiology to describe the process by which the origin or source of a cluster of contaminated food is identified.
Food Safety Implication: Tracebacks may stop the additional sale and distribution of contaminated food, thus preventing further exposure or spread of the infection. For example, if an outbreak is determined to be caused by a suspected food, investigators conducting the traceback analysis would determine where the restaurant or grocery store purchased the food, who supplied the wholesaler, and finally, on which farm it was grown.
Since wholesalers and retailers often buy food from multiple vendors, the traceback to the farm step requires extensive detective work. The various stages that the food traveled would be examined to deduce where the pathogen was transferred to the product.
A process in which genes from a bacterium are incorporated into the genome or chromosome of a bacteriophage (a virus that attacks bacteria) and then carried to another host cell when the bacteriophage initiates a new cycle of infection. (Also see Bacteriophage.)
The passing of genetic material in the form of deoxyribonucleic acid (DNA) between bacteria. One bacterium, called the donor cell, gives DNA fragments to another bacterium, called the recipient cell.
> Transovarian Transfer
When certain pathogens, notably Salmonella Enteritidis, can infect the ovaries of hens and thus, infect the eggs as they are being formed in the ovaries. (Also see Competitive Exclusion and Salmonella.)
Food Safety Implication: Transovarian transfer occurs without harming the bird or stopping the egg production. The pathogens end up inside the egg (on the surface of the yolk), so that no amount of washing of the egg shell will remove or kill the Salmonella Enteritidis bacteria. All eggs laid by an infected hen do not carry the bacteria, which makes it more difficult to pinpoint the problem.
A life-threatening illness caused by the bacterium Salmonella Typhi. In the United States, about 400 cases of typhoid fever are identified each year, and 75% of these cases are acquired while traveling internationally.
Sources: Food or beverages that have been contaminated with bacteria that gets into the water used for drinking or washing food or handled by a person who is shedding (excreting the bacteria in their stool) Salmonella Typhi.
Incubation: 1 to 4 weeks, usually 2 weeks.
Symptoms: Fever, stomach pains, headache, loss of appetite, and weakness. In some cases, patients have a rash of flat, rose-colored spots.
Duration: Once asymptomatic (presenting no symptoms of disease), it can be ongoing.
See the "Did You Know?" on Typhoid Mary at left and the Frequently Asked Question below.