Submitted to: Meeting Abstract
Publication Type: Proceedings
Publication Acceptance Date: 5/1/2006
Publication Date: 7/13/2006
Citation: Maricato, E., Arcuri, E., Lange, C.C., Brito, M.A., Souza, G.N., Luchansky, J.B., Cerqueira, M.M., Brito, J.R. 2006. Seasonal prevalence of food borne pathogens in retail samples of pasteurized milk and minas frescal cheese from juiz de fora, brazil. Meeting Abstract. Revista do Instituto de Laticinios Candido Tostes, Juiz de Fora, MG 61(n)351:207-210. Interpretive Summary:
Technical Abstract: We studied the influence of the dry/cold and hot/humid seasons on the prevalence of Listeria monocytogenes and Staphylococcus aureus in retail samples of pasteurized milk (PM) and Minas frescal cheese (MFC) from Juiz de Fora, State of Minas Gerais, Brazil. A total of 104 PM samples (9 brands; 54 in the winter of 2005 and 50 in the summer of 2006) and 100 MFC samples (10 brands, 50 in each season) were examined. Suspect colonies recovered from selective media were confirmed by PCR. Only S. aureus was recovered from PM; one brand/sample tested positive in winter of 2005 and 2 brands/samples tested positive in summer of 2006. S. aureus was also recovered from 14/50 (28%) MFC samples representing 6/10 brands (60%) in the winter, and from 15/50 (30%) samples representing 6/10 (60%) brands in the summer. Likewise, L. monocytogenes was recovered from 4/50 (8%) samples from 1/10 (10%) brands in the winter, and presumptive isolates of the pathogen were recovered from 14/50 (28%) samples from 6/10 (60%) brands in the summer. Of note, 9/22 (40%) environmental samples and all 5 cheese obtained directly from the associated dairy, that being plant F, which produced cheese testing positive for Lm in winter at retail also tested positive for L. monocytogenes. Several improvements in the plant’s design and layout, as well as improvements in how the cheese was processed and stored, eliminated the pathogen from plant F and the cheese which it produced upon subsequent analyses 2 and 4 months after the original sampling. These data suggest that L. monocytogenes and S. aureus are the pathogens of primary concern for both PM and MFC and that further research is needed to reduce the risks these pathogens pose to consumers. Thus, experiments are ongoing to extend both the sampling size and sampling period, as well as to sample for Salmonella spp. and Escherichia coli O157:H7, to identify and better manage sources of contamination from farm through retail.