Salmonellae in minced pork - Dissemination, reasons, prevention

Food of animal origin has been incriminated to a large extend for the incre ase in foodborne infections caused by salmonellae. One important reason are latent infections in intensive pig production units, which lead to meat su rfaces and musculature contaminated with salmonellae, without being arreste d during ante and/or post mortem inspection, finding their way into the fin al product and posing a health hazard to the consumer. Considering this fact in the framework of a doctor thesis (GROSSKLAUS, 1997 ) minced pork on the market was investigated to find out the degree of salm onella contamination, to elaborate the reasons for this hygienic deficiency , and to develop proposals for its elimination. Experimental studies were carried out basing on 300 minced meat samples fro m three retail shops of a supermarket chain. 34 samples = 11.3 % of the min ced pork samples were found to be positive for salmonellae immediately afte r purchase. Only in 17 cases out of a total of 300, i.e. in 5,7 % of all sa mples salmonellae were found in all three investigation steps (1. imediatel y after purchase, 2. after three hour storage time at 8 degrees C an 3. aft er twentyfour hour storage time at 22 degrees C). These 17 samples were poo led and their MPN was examined. 4 - 2500 colonies were found in 100 g sampl es. Total viable counts varied between 1.0 x 10(9) and 6.3 x 10(7) per g. D ata collected in 1991 and 1992 from 771 cases of foodborne infections from three Berlin districts, revealed minced meat only in 9 cases to be the like ly cause of infection. Samples tested after different storage times and tem peratures reveales differences in salmonella findings, underlining a phenom enom of uneven distribution of salmonella organisms ("nest formation") in t he minced meat. The microbiological status and thus the overall hygiene status of a meat pr ocessing plant correlations only by chance with the occurence of salmonella . The relatively small numbers of salmonella cells found, and the low perce ntage of minced meat regulations in force. Regardless of the above, there i s room for improvement of collecting and recording the data of cases of ent eritis in fectivia and their epidemiological evaluation according to the fe deral commericable diseases act. Considering the wide distribution of salmonellae in minced pork and the con tinous presence of the organism in the slaughter stock, ways are discussed to curtailing the latent salmonella in the fattening units, in an attempt t o prevent, or at least reduce the causal agent entering the food chain from harvest to production.