Microflora of Edible Offal with Particular Reference to Salmonella

Feeding of raw offal has been suspected to be a major source of Salmonella infections among pets, particularly among dogs, in the city of Berlin (West). The present study revealed that 231 (56.6%) of 408 samples of edible offal (liver, lungs, heart, bovine rumen, porcine esophagus) contained 24 types of Salmonella . Salmonella typhimurium prevailed (145 samples = 62.8% of the positive samples = 35.5% of the total), including 8 strains of S. typhimurium var. copenhagen . Three types had an incomplete seroformula. The investigation covered a period of 26 months. The percentage of positive findings did not significantly differ during various seasons. Positive findings were most frequent with porcine esophagus (40/49) and least frequent with imported swine liver (17/58) and bovine rumen (13/45). Presence of salmonellae was not correlated with other microbiological criteria, in particular aerobic plate count and number of Enterobacteriaceae . All samples were sold at West-Berlin's central wholesale meat market and originated from slaughter animals judged as "fit for consumption", which means that they were also intended for human consumption and not only as animal feed. Repeated isolation of the same Salmonella type from different samples taken on the same day indicated rapid spreading during transport and storage. This contamination did not persist for a longer period but was replaced by other strains which subsequently appeared. Since raw offal for retail sale represents a considerable health hazard, it is recommended that this material should not be offered for retail sale unless in hermetically sealed packages. Packages should have labels with directions for proper handling of the contents in the home. Warning should also be given that viscera should neither be eaten raw nor fed to pets unless the material is adequately heated.