Assessment of the microbiological quality of retail fresh pork meat in central Italy

An assessment of the microbiological quality of retail fresh pork meat was conducted with two microbial isolation methods (swab, disruptive) on 108 samples from two muscle types (Longissimus thoracis and masseter), collected from 18 outlets of two retail types (supermarkets and butcher's shops) in three provinces of the Latium region (central Italy). Counts ranged from 2.2 to 5.4 log cfu/g for total mesophilic bacteria, from 0.09 to 5.6 log cfu/g for thermophilic bacteria, and from 1.3 to 4.3 log cfu/g for coliforms. On the average, the disruptive method gave higher colony counts by a factor of 2.4. Residual variability was mostly due to muscle type and only to a limited extent, to the retail outlet or sampling visit. The frequency of positive samples detected with the disruptive method was 19% for E. coli, 16% for Staphylococcus spp., 19% for Salmonella spp., 29% for Campylobacter spp., 11% for B. thermosphacta and 20% for lactic acid bacteria; in general the method was two to five times more efficient than the swab method. Method agreement was quite low for both analytical determinations and overall quality assessment. Compared with EU reference values, the swab method was stricter in assessing microbiological quality, signalling over one-tenth of the samples as unacceptable on mesophilic counts and about two thirds on coliforms counts, while 6% on coliform counts and 19% on Salmonella tests were rated as unacceptable according to the Italian Zooprophylactic Service reference based on the disruptive method.