Fate of selected pathogens in vacuum-packaged dry-cured (country-style) ham slices stored at 2 and 25°C

• Published in: Journal of food protection 1997-12, Vol.60 (12), p.1541-1547
• Main Authors: WOOI FANG NG, LANGLOIS, B. E, MOODY, W. G
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Food industries; Fundamental and applied biological sciences. Psychology; Meat and meat product industries
• ISSN: 0362-028X; 1944-9097
• DOI: 10.4315/0362-028X-60.12.1541

Whole dry-cured (country-style) hams from six manufacturers were sliced and the slices randomly allotted into five treatment groups per manufacturer. One treatment group served as a control and slices in the four other treatment groups were inoculated with approximately 10 CFU/g of ham of either Escherichia coli O157:H7, Listeria monocytogenes , a mixture of three Salmonella spp. ( Salmonella typhimurium , Salmonella enteritidis and Salmonella choleraesuis ), or Staphylococcus aureus . All ham slices were vacuum-packaged with half of the packages in each treatment group stored at 25°C and half stored at 2°C. Two packages from each manufacturer for each treatment and storage temperature were examined after storage for 0,7, 14,21, and 28 days. S. aureus was detected in 2 of 60 control slices, Salmonella in 2 of 120, L. monocytogenes in 4 of 120, and E. coli O157:H7 was not detected in any of the 120 control ham slices analyzed before or after storage. Aerobic (26 and 35°C) populations of the control vacuum-packaged hams slices increased ( < 0.05) with storage time and the increase in populations was greater ( < 0.05) in vacuum-packaged hams slices at 25 than at 2°C. The extent of the decreases in populations of the inoculated pathogens during storage of vacuum-packaged dry-cured ham slices varied with manufacturer ( < 0.05) and storage temperature ( < 0.05). Decreases in Salmonella spp. and E. coli O157:H7 populations were greater ( < 0.05) in slices stored at 25 than at 2°C, while decreases in L. monocytogenes were similar at both storage temperatures. Staphylococcus aureus enterotoxin was not detected in either S. aureus -inoculated or control ham slices after storage for 28 days. Survival of these pathogens in vacuum-packaged dry-cured ham slices suggests that contaminated hams may pose a safety risk to consumers if consumed without adequate cooking.