Foodborne Infection

CHAPTER 1, FOOD SAFETY

Foodborne Infection:

(1) A foodborne infection is caused by the ingestion of food

containing pathogenic microorganisms (i.e bacteria, virus or parasite)

which must multiply with in the gastrointestinal tract, producing

widespread inflammation. The most commonly implicated microorganisms

include species of Salmonella, Shigella, E. coli 0157:H7, etc. These

infections have longer incubation periods than those experienced with food

intoxications, usually commencing from 6-24 hours or longer after

ingestion. Symptoms may include fever, headache, nausea, vomiting,

diarrhea, abdominal pain or distress, and prostration. The causative

organism may be identified by laboratory examination of the vomitus, feces,

or blood and the suspected food, when available.

(2) Foods most commonly incriminated in outbreaks of foodborne

infections are meat and seafood mixtures such as hash, hamburger, creamed

meat pies, crab, lobster, chicken, and turkey salads, turkey, turkey

stuffing or dressing, chicken, and ham. These foods have common

characteristics in that they provide moisture, a good protein food supply

and warmth. Given sufficient time, these factors promote an ideal

environment for the growth and multiplication of microorganisms. It is

important to remember that these organisms do not necessarily cause any

alteration in the normal appearance, odor, or taste of the food.

c. Foodborne Intoxication:

(1) Certain bacteria under favorable growth conditions produce

chemicals (toxins) in food which when ingested will cause food

intoxication. Enterotoxins produced by Staphylococcus aureus are heat

stable (i.e., not destroyed by normal cooking temperatures) and are the

cause of the most common foodborne intoxication. The staphylococci

multiply in the food where they produce their toxins before the food is

consumed. It generally takes less than 8 hours for these organisms to

elaborate enough toxins to cause symptoms. The disease is characterized by

an abrupt onset (2 to 4 hours after ingestion) of symptoms of severe

nausea, vomiting, diarrhea, and prostration with little or no fever.

(2) Staphylococcal food intoxication usually follows ingestion of

starchy food, especially potato salad, custard and pies. When the offending

food is meat, pork (including ham and salami) and poultry products are

usually the source. Ham may become contaminated with staphylococci during

the practice of boning, slicing and holding without adequate refrigeration

for several hours before serving. In addition, highly salted ham permits

staphylococcal growth but inhibits many other bacteria. Other foods

commonly involved are canned or potted meat or fish, pressed tongue, beef,

cheese, other milk products, cream or custard filled pastries, potato

salad, and pasta salads. The usual source of the pathogens, which cause

this form of food intoxication, may be the nose, throat, boils, pimples, or

infected cuts on the hands of food service personnel.

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