Large numbers of organisms in food may cause bacterial infection. The bacteria grow rapidly in the moist warm intestinal environment and in 12 to 36 hours produce symptoms such as fever, vomiting, distention, cramping, and diarrhea. The illness is usually mild, lasts for two or three days, and is not usually reported to public health authorities. The dehydration and electrolyte imbalance that sometimes occur are poorly withstood by infants and elderly people.
Salmonella account for a high incidence of bacterial infections. Meat, poultry, fish, eggs, and dairy products that are eaten raw or inadequately heated are frequently the source of infection. For example, raw egg in an eggnog may be the source; or a butcher block, kitchen counter, or utensil that has been in contact with raw meat or poultry could contaminate another food placed upon it.
Typhoid fever is caused by a species of Salmonella. It was a major public health problem at the beginning of this century, but the illness is now uncommon because of the greater safety of water and milk supplies.
Clostridium perfringens, also known as the gas gangrene organism, appears normally in the soil, in sewage, and in the intestinal tract of man. The bacteria are readily destroyed by heat, but the spores survive even after five or six hours of heating. If a cooked food such as meat or gravy is allowed to stand at room temperature for several hours, the spores germinate and produce tremendous numbers of bacteria. If the food so grossly contaminated is eaten, it produces the typical gastrointestinal upsets. Such infections do not occur when food is eaten immediately after cooking. Nor do they occur if food is refrigerated promptly after cooking so that the spores do not germinate. However, if large masses of foods are refrigerated, considerable growth of bacteria can occur before the center of the food mass is adequately chilled; therefore, such foods should be spread out in thin pans for rapid cooling.
Other bacterial infections that may be food borne are shigellosis (bacillary dysentery), brucellosis (undulant fever) from raw milk from infected animals, tularemia (rabbit fever), and streptococcal infections, such as strep throat and scarlet fever.
Viral infections include the common cold and infectious hepatitis. The infections are transmitted by direct contact or by contamination of food or water supplies.
*104/234/5*
GENERAL HEALTH
