SOURCE FORMATION PERIOD SYMPTOMS FOOD INFECTION INCUBATION PERIOD SYMPTOMS MORTALITY RATE FOOD INTOXICATION BOTULISM SOURCE PERIOD OF INCUBATION SYMPTOMS MORTALITY RATE ADULTERATION OF FOOD MEANS OF MOST COMMON ADULTERATIONS CHAPTER XVI FOOD POISONS Sources In most instances such poisoning comes from food that is preserved in some way. Very seldom do we find this poisoning in fresh foods. Such prepared foods as chopped meats, sausage, meat pies and salads, for example furnish the best sources for this poisoning. The formation period of the poison usually covers from eight to twenty-eight hours. There are two classes of food poisoning: first, food infection; second, food intoxication. Clinically, there is a great difference between them. Food infection is an acute condition in which there is nausea, vomiting, cramps, diarrhœa and fever. Food intoxication is a febrile condition characterized by nervous symptoms, paralysis and constipation. In food infection the mortality is seldom above 1%, while in food intoxication it runs from 50% upward. The condition resulting from food intoxication is known as botulism. The statistics which are available on food poisoning would indicate that it is not very prevalent and the number of persons involved in outbreaks is comparatively small. Many conditions in which there are gastro-intestinal symptoms might be mistaken for food poisoning. Such symptoms as nausea, cramps, vomiting or diarrhœa may be due to acute gastric indigestion, and may not be in any way associated with food poisoning. Foods containing such poison should be thoroughly cooked so that the heat may penetrate to the very center. A temperature of 70° C. is sufficient to render the food free of the poison. Food Infection The incubation period of food infection is usually from six to twelve hours from the time the food is taken into the stomach until the manifestation of symptoms. This period may in some cases be reduced to only four hours, while in others it may be extended to seventy-two or more hours. This class of food poisoning is sometimes called meat poisoning from the fact that meat forms its chief vehicle, but milk and milk products and even vegetables may contain it.