What is Food Poisoning?
Food-poisoning, a term that generally refers to outbreaks of acute illness-pain, vomiting and diarrhea which occur shortly after a meal. Food-poisoning is caused principally by the contamination of food by bacteria which multiply rapidly under suitable conditions.
Fifty per cent of cases are caused by bacteria of the Salmonella group, which get into the food from animal or human excreta. Salmonella food-poisoning is characterized by sickness, diarrhea and fever, developing within 24 hours· attacks may last from one to eight days. Certain strains of Staphylococcus produce a toxin within the intestine which causes a violent attack from two to six hours after eating infected food; the attack lasts from 12 to 24 hours. The majority of cases are caused by nasal carriers.
Miscellaneous bacteria that are resistant to cooking temperatures may grow in stored cooked food and cause mild attacks of abdominal pain with diarrhea but no vomiting.
Botulism is due to the growth of an anaerobic organism, Clostridium botulinum , the spores of which are very heat-resistant. The toxin attacks the central nervous system. In Europe, where cases are caused mainly by eating contaminated meat or fish, the mortality rate is about 25 per cent. In the USA cases most frequently follow the ingestion of home-canned vegetables or fruit, and the death rate is about 70 per cent.
Some poisoning may be caused by chemicals, such as arsenic, used as weedkillers or insecticide sprays on fruit and vegetables.
The extension of communal feeding in recent years has led to a marked increase in the incidence of food poisoning. Another cause is the increased sale of ready prepared foods . Foods liable to carry infection include cooked meats, sausages, soups and stews, cream buns, meat pies, fish-cakes, duck eggs, and shellfish. Lack of personal hygiene among those who handle and prepare food is the major cause of infection. Bacteria from the intestines, nose and throat, or from septic cuts, may be conveyed via the hands. Animals such as mice, rats, cats, dogs, flies, or cockroaches may also be a source of infection. Once food has been infected, keeping it at a heat near body temperature will cause a rapid increase in the growth of the bacteria.
Prevention necessitates (1) strict control of foods for sale, to avoid infected food being made available on the market; (2) cleanliness in the distribution of food; (3) high standards of hygiene among those handling food and in places where cooked food is prepared and served. High temperatures destroy bacteria; clean storage and refrigeration prevent their growth.