Safety conditions and native microbial flora of three processing units in Alentejo , Portugal

Abstract

Portugal as other Mediterranean countries has a great diversity of dry fermented sausages. This traditional sausage production is highly diverse and products possess very particular organoleptic characteristics, which please consumers. These sensory characteristics are related not only to the manufacturing process, but also to the house microbial flora. On the other hand, the safety of fermented products is always difficult to achieve due to their processing technology and final characteristics, as the process does not have any step able to undoubtedly eliminate pathogens, according to HACCP approach. In this kind of products, coagulase negative staphylococci (CNS) and lactic acid bacteria (LAB) are present in high levels. These bacteria are responsible for the particular taste and flavour and also for extending the shelf life of sausages. LAB are useful particularly for the ability to produce bacteriocins that are generally active towards several foodborne pathogens, such as Escherichia coli, Listeria monocytogenes and Salmonella sp., while CNS are mainly nitrate reducers, thus contributing to flavour development. The aim of this study was to determine the occurrence of Salmonella sp., L. monocytogenes and E. coli in different surfaces of the three visited processing units as well as in meat batters, half ripened and final products (Portuguese traditional sausages). Furthermore, we also evaluated the total number of mesophiles in each surface and product, as well as the number of CNS and LAB. Surfaces were generally well hygienised, only a few presenting with low contamination levels by L. monocytogenes and E. coli. No contamination with Salmonella sp. was detected in the diverse analysed products independently of their processing stage. However, different contaminations levels with L. monocytogenes and E. coli were found in distinct processing units.