Evaluating Pediococcus acidilactici and Enterococcus faecium NRRL B-2354 as Thermal Surrogate Microorganisms for Salmonella for In-Plant Validation Studies of Low-Moisture Pet Food Products.

Pediococcus acidilactici ATCC 8042 and Enterococcus faecium NRRL B-2354 were investigated as potential surrogates for Salmonella serovars using thermal death time kinetics in products such as dry pet foods. The D-values of P. acidilactici ATCC 8042, E. faecium NRRL B-2354, and a cocktail of seven Salmonella serovars associated with low-moisture products were determined in a preservative-free dry pet food product at moisture levels of 9.1, 17.9, and 27.0% and heated between 76.7 and 87.8°C. The D-values were calculated by least squares linear regression. The D-values of P. acidilactici ATCC 8042 were higher than those for the Salmonella serovar cocktail but lower than those for E. faecium NRRL 2354. At 9.1% moisture, D-values of 6.54, 11.51, and 11.66 min at 76.7°C, 2.66, 3.22, and 4.08 min at 82.2°C, and 1.07, 1.29, and 1.69 min at 87.8°C were calculated for Salmonella serovars, P. acidilactici ATCC 8042, and E. faecium NRRL B-2354, respectively. The data suggest that the thermal inactivation characteristics of P. acidilactici ATCC 8042 can be utilized as a surrogate to predict the response of Salmonella in dry pet food products that are thermally processed at <90°C.

Rapid Assessment of the Microbiological Quality of Poultry Carcasses Using ATP Bioluminescence.

The meat industry is in need of faster and more reliable methods to determine microbial loads in food products. A rapid method (<15 min) has been developed to assess the microbiological quality of chicken carcasses using the adenosine triphosphate (ATP) bioluminescence assay. The results indicate that, following modifications, the ATP bioluminescence test produced an acceptable correlation with plate counts (r = 0.85, p < 0.001) and demonstrated good repeatability between replicates. It is envisaged that the modified ATP bioluminescence assay would best be used as a platform rejection test. Using threshold levels determined from the regression equation, the ATP bioluminescence assays gave about 90% agreement with plate counts for carcass rinses with counts above 5 × 104 CFU/ml. These findings suggest that the modified ATP bioluminescence assay could be used for monitoring critical control points (CCPs) in programs based on hazard analysis of critical control points (HACCP).