Bacteriological Investigation of Alberta Meat-Packing Plant Wastes with Emphasis on Salmonella Isolation

Abstract

The waste treatment facilities and final effluents of 11 meat-packing plants in the Province of Alberta were investigated primarily to determine the numbers of indicator bacteria and the presence of Salmonella. This was done to discover the efficiency of the treatment systems presently in operation in reducing bacterial numbers and to establish the need for disinfection and for bacterial standards for these effluents. Data obtained showed that the final effluents were of very poor quality bacteriologically, with numbers of indicator organisms comparable to those found in raw sewage. Primary treatment facilities were ineffective in reducing the numbers of these bacteria. The secondary treatment facility investigated achieved greater than a 99% reduction of indicator bacteria. Salmonella were isolated from the final effluents of 78% of the plants, including the plant using secondary treatment. In total, 21 Salmonella serotypes were isolated. Salmonella isolates were not antibiotic resistant, but certain coliform and fecal coliform isolates demonstrated resistance to chloramphenicol, tetracycline, and ampicillin.