Streptococcal contamination of food: an unusual cause of epidemic pharyngitis.

The purpose of this article is to define the distinguishing characteristics of food-borne streptococcal pharyngitis by reviewing the literature. The main cause of this infection lies in poor handling and preservation of cold salads, usually those which contain eggs and are prepared some hours before serving. A shorter incubation period and a higher attack rate (51-90%) than in transmission by droplets was noted. The epidemics tend to occur in warm climates and in the hottest months of the year. Streptococcus pyogenes seems to originate from the pharynx or hand lesions of a food handler. In comparison to airborne transmission symptoms such as sore throat, pharyngeal erythema, and enlarged tonsils, submandibular lymphadenopathy are more frequent than coughing and coryza. Seven out of 17 reports revealed an M-untypeable serotype, which may possess virulent characteristics. Penicillin prophylaxis was shown to limit additional spread of the infection. There were no non-suppurative sequels, and suppurative sequels were very rare. We assume that the guidelines for the prevention of food poisoning would apply to food-borne streptococcal pharyngitis. Food handlers should be supervised to ensure they comply with strict rules of preparation and storage of food. Cold salads, especially those containing eggs, should not be left overnight before serving.