Microbial Quality of Vacuum Packaged Sliced Ham ¹

A total of 60 paired samples of vacuum packaged sliced ham was purchased at retail stores and analyzed for microbial quality as new (less than 10 days from manufacture) and old product (held to manufacturer's pull date at 4 C). Microbial counts of new product were variable, but at the product pull date, counts reached 10⁸ per g. Differences in microbial load were noted between manufacturers. Although it might be expected that lactic acid bacteria would make up the predominant part of the microflora, this was not confirmed by the Lactobacillus count or pH drop. Lactobacilli formed a variable component of, and seldom predominated, the total population. The pH did not drop markedly as product aged, and pH change differed between products from several manufacturers. A protective effect could not be predicted from pH of these ham samples. Other bacteria, including Microbacterium thermosphactum , micrococci and group D streptococci were of minor importance, and potential pathogens were absent in these samples, at their respective minimum detectable levels. The vacuum packaged sliced ham obtained for analysis from retail stores for this study was of sound microbial quality.