YERSINIA-ENTEROCOLITICA - REVIEW OF ITS ROLE IN FOOD HYGIENE

Abstract

Since Y. enterocolitica, now classified as a member of the Enterobacteriaceae, was recognized as a distinct species in 1964 it has been isolated with increasing frequency from man and animals (including dogs and pigs) and from some human foods. Y. enterocolitica infections are now seen as a cause for some concern in human and veterinary medicine. The organism is commonly found in specimens from swine slaughterhouses and has been isolated from samples of market meat, vacuum-packed beef, mussels, oysters and ice-cream. It has also been found in nonchlorinated well water used for drinking purposes. Infections in man therefore probably have an alimentary origin. Only 23 human infections were recorded in 1966 but the number increased to > 4000 in 1974. However, reported incidence is affected by growing awareness about the role of the organism in human and animal disease and by intensive laboratory analyses. While knowledge about the geographical distribution of Y. enterocolitica is still fragmentary, infections are apparently very frequent in some parts of the world and probably common but unrecognized in many countries. The most common symptoms of Y. enterocolitica infections in man are fever, abdominal pain and diarrhea. In the USA most isolations in human infections were made from blood and mesenteric lymph node samples. The pathogenic mechanism is not known. In 1 experiment involving a human volunteer subject a dose of 3.5 .times. 109 organisms was required to produce an infection. Recently some success was obtained in establishing experimental infections in mice, guinea pigs, rats and rabbits. Laboratory cultivation techniques for Y. enterocolitica are described together with a table of minimal tests for characterizing the organism and 2 biotyping schema. Little is known about methods for controlling this disease, but environmental hygiene and sanitation with regard to food and water should apply.