Assessment of Microbial Populations in the Manufacture of Vacuum-Packaged Ready-to-Eat Roast Beef and in a Related Production Plant
Articolo
Data di Pubblicazione:
2019
Citazione:
Assessment of Microbial Populations in the Manufacture of Vacuum-Packaged Ready-to-Eat Roast Beef and in a Related Production Plant / M.P. Beccalli, C. Picozzi, N. Mangieri, I. Vigentini, R. Foschino. - In: JOURNAL OF FOOD PROTECTION. - ISSN 0362-028X. - 82:1(2019 Jan), pp. 58-64. [10.4315/0362-028X.JFP-18-147]
Abstract:
Some microbiological criteria were monitored for 6 months in vacuum-packaged roast beef (15 production batches), raw
beef (10 batches), and other meat products (12 batches) produced in an Italian small to medium-size enterprise. Fifty-five
environmental swab samples also were analyzed. The main bacterial groups were identified by cultural methods according to
International Organization for Standardization standards. Listeria monocytogenes was enumerated with the most-probablenumber
protocol, and species identification was confirmed with a specific PCR assay. Immediately after vacuum packaging, all
ready-to-eat (RTE) products had low mean aerobic colony counts (,102 to 2.43102 CFU g1), anaerobic colony counts (1.6 to
6.5 3 101 CFU g1), Enterobacteriaceae counts (1.1 to 1.4 3 101 CFU g1), and Escherichia coli counts (generally below the
detection limit). Nevertheless, the prevalence of L. monocytogenes in these samples was 3.7%. In roast beef samples, the aerobic
and anaerobic colony counts reached unacceptable levels (.106 CFU g1) after 14 days of refrigerated storage. Because the
prevalence of L. monocytogenes increased to 13.3% during storage, a substantial reduction in the shelf life of these products is
recommended. Surfaces without direct contact with food (floors and drains) had the highest mean counts for aerobic colonies (8.0
3103 to 9.53105 CFU/cm2), anaerobic colonies (2.93103 to 3.23104 CFU/cm2), Enterobacteriaceae (1.53101 to 8.43101
CFU/cm2), and E. coli (6.0 to 7.7 CFU/cm2). The levels of L. monocytogenes on direct food contact surfaces were below the
detection limit, but more than 25% of floor samples were contaminated. These results reveal the persistence of L. monocytogenes
in food processing environments, although at very low levels, posing a high risk of postcooking recontamination for RTE
products. To improve hygienic conditions and reduce cross-contamination, an increase in operator awareness and a reassessment
of surface sanitization protocols are needed.
Tipologia IRIS:
01 - Articolo su periodico
Keywords:
Escherichia coli; Listeria monocytogenes; Ready-to-eat meat products; Roast beef; Vacuum packaging
Elenco autori:
M.P. Beccalli, C. Picozzi, N. Mangieri, I. Vigentini, R. Foschino
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