Public health authorities in Oxford, Middlesex and Elgin Counties, Ontario, seized raw milk Cheddar cheese due to presence of Salmonella muenster. Investigations by these units and the University of Guelph traced the source of Salmonella to one particular milk supplier shipping to a cheese factory. Analysis of milk samples from a herd of 35 cattle revealed only one cow shedding S. muenster directly into the milk (ca. 200 CFU/ml). Eleven of 181 vats of cheese, produced at the factory between May and October 1982, were positive for Salmonella at the curd stage. Only 2 vats of the finished raw milk Cheddar, however, were positive. One lot of Salmonella-positive cheese was still positive after the legally required 60-d holding period and remained so for 125 d.
Two hundred and fourteen consumer milk samples from across North America were examined for antibiotics residues by means of the Bacillus stearothermophilus disc assay (Charm test) and the competitive isotopic (Charm Test II) procedure. Of the 174 samples taken from 16 states, 150 results were positive for one or more antibiotics. The greatest number of positives were sulphamethazine, 82, and tetracyline, 48. Candian samples, 40, also showed the same problem related to tetracycline, 12, and sulphamethazine residues, 12. The Bacillus stearothermophilus disc assay procedure was unable in most cases to detect these residues possibly due to the lower sensitivity of this test. Further comparative tests between Charm Test II and other methods of similar sensitivity are recommended to confirm these findings.
The data collected from studies to monitor inactivation of Escherichia coli O157:H7 in uncooked fermented salami were used to develop models to describe survival of the organism. Three models were developed that included different variables to best describe E. coli O157:H7 reduction. Model A included the variables water activity (a(w)), pH, time, and quadratic variables pH and time. Model B separated the processing stages into fermentation and drying. The fermentation included the variables pH and temperature x time (ttarea) and interaction between the two variables. The drying stage was modeled using the variables time and a(w) and interaction between the two. Model C looked at variables a(w) and the time at pH 5.3 to achieve a 2-D log reduction of E. coli O157:H7 and the interaction between the variables. The variables selected for inclusion in all the models were significant at the P < 0.0001 level. The predicted values for all models correlated well to the observed values with R2 of 0.888, 0.828, 0.836, and 0.818 for models A. Bferm, Bdrying, and C, respectively. The models were validated using data from a trial not used to develop the model. In general the predicted reduction in E. coli O157:H7 count in uncooked fermented salami was greater than for the observed E. coli O157:H7 log reductions for all models, but the relation between the two was linear. The results demonstrate that modeling can be a useful tool in assessing manufacturing practices for uncooked fermented salami processes.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.