There has been a renewed interest in the occurrence of salmonellae in food products, prompted mainly by recent disclosures that the organisms were recovered from a wide variety of foods. The 1,200 or more serotypes of these Gram-negative, facultative, asporogenous, rod-shaped bacteria are all considered to be human pathogens. In man they can cause enteric fevers (i.e., typhoid fever and related ailments), gastroenteritis, and septicemias. Treatment of salmonellosis is often difficult, and a limited number of patients continue to shed the organisms for extended periods even though they appear to be recovered. During 1966 there were approximately 17,000 reported cases of salmonellosis in the United States. This is an increase from 6,693 in 1957. Cases of typhoid fever decreased by nearly 75% during this same period. It is believed by some that the number of reported salmonellosis cases represents from 1 to 5% of the actual cases in the United States. Reported deaths in the United States from all types of salmonellosis averaged slightly less than 100 annually during the 1957–1966 period. Although most outbreaks of human salmonellosis are attributable to such animal products as eggs and meat (mainly poulry), dairy products, on occasion, have been reported as vehicles for the spread of this ailment. Salmonellae grow at temperatures of 5.5 to 45 C, at αw values of 0.945 to 0.999, are retarded by acids and are inactivated if the pH is low enough, are destroyed by conventional pasteurization treatments, are easily destroyed by chlorine and quaternary ammonium compounds, can survive but not grow in media with 15 to 30% sodium chloride, and may be inhibited by sorbic acid. Salmonellae are known to occur in raw milk, but the frequency and level are unknown. Consumption of contaminated raw milk has led to outbreaks of salmonellosis. Pasteurized milk, too, has been responsible for disseminating these organisms which occurred in the product through contamination after heating. Occurrence of salmonellae in certain dairy products has been demonstrated in the United States and elsewhere. This review of the literature further discusses the circumstances under which these organisms may occur in dairy products or ingredients used in combination with dairy products in the preparation of various foods. © 1969, American Dairy Science Association. All rights reserved.
