Microbial pathogen quality criteria of rendered products

The North American rendering industry processes approximately 24 million metric tons (Mt) of raw materials and produces more than 8 million Mt of rendered products. More than 85 % of rendered products produced annually in the USA are used for producing animal feed. Pathogen contamination in rendered products is an important and topical issue. Although elevated temperatures (115-140 °C) for 40-90 min during the standard rendering processes are mathematically sufficient to completely destroy commonly found pathogens, the presence of pathogens in rendered products has nevertheless been reported. Increased concern over the risk of microbial contamination in rendered products may require additional safeguards for producing pathogen-free rendered products. This study provides an overview of rendered products, existing microbial pathogen quality criteria of rendered products (MPQCR), limitations, and the scope of improving the MPQCR.

Bacterial contamination of animal feed and its relationship to human foodborne illness

Animal feed is at the beginning of the food safety chain in the "farm-to-fork" model. The emergence of variant Creutzfeldt-Jakob disease has raised awareness of the importance of contaminated animal feed, but less attention has been paid to the role of bacterial contamination of animal feed in human foodborne illness. In the United States, animal feed is frequently contaminated with non-Typhi serotypes of Salmonella enterica and may lead to infection or colonization of food animals. These bacteria can contaminate animal carcasses at slaughter or cross-contaminate other food items, leading to human illness. Although tracing contamination to its ultimate source is difficult, several large outbreaks have been traced back to contaminated animal feed. Improvements in the safety of animal feed should include strengthening the surveillance of animal feed for bacterial contamination and integration of such surveillance with human foodborne disease surveillance systems. A Hazard Analysis and Critical Control Point program should be instituted for the animal feed industry, and a Salmonella-negative policy for feed should be enforced.

The reliability of the examination of foods, processed for safety, for enteric pathogens and Enterobacteriaceae: a mathematical and ecological study

Because of the paucity of quantitative data on numbers of other enteric pathogens in food, the reliability of the examination of processed foods for Enterobacteriaceae was estimated taking Salmonella as a model. For this purpose an assessment was carried out of the risk of accepting Salmonella contaminated consignments of foods, despite a negative outcome of (i) examination of 1.5 kg samples for Salmonella; (ii) examination of one or two 1 g samples for Enterobacteriaceae; (iii) simultaneous application of both tests. The computations were based on the results of the examination of 6830 samples of dried foods, processed for safety, out of a total of 18170 samples.Only 69 samples permitted the exact calculation of the epsilon-factor, defined as c.f.u./g of Enterobacteriaceae/c.f.u./g of Salmonella; 4642 were positive for the former group but ;free' from Salmonella, and the rest were negative in both tests. Numbers of c.f.u./g for both groups, and hence the epsilon-factors, varied widely between commodities and also between different consignments of the same food product. The average for epsilon amounted to 5.8 x 10(3), far from the base-line value of 0.75 x 10(3) assessed earlier. In only 0.1% of samples did the Enterobacteriaceae test fail to achieve the required consumer protection.This investigation therefore substantiates that testing foods processed for safety by examining accurately chosen quantities for ecologically well selected and taxonomically thoroughly defined index organisms is a most effective procedure in terms both of consumer protection and simplicity of examination without compelling the food industry to achieve hardly attainable microbiological quality standards.