No abstract

Since most food plants have cold wet growth niches in production and storage areas, susceptibility testing should be performed on biofilms produced at refrigeration temperatures. Moreover, the efficiency of the sanitizers used in food industries should be performed on mixed culture biofilms, since in field conditions these will predominate. The results presented here highlight the importance of the temperature used for biofilm formation, when susceptibility to disinfectants is being assessed, as biofilms produced at lower temperature were less susceptible to sanitizers.

Abstract:The purpose of this study was to investigate the presence of β-lactam-resistant bacteria in six different types of Portuguese cheese. The numbers of ampicillin resistant (AMP r ) bacteria varied from 4.7  10 2 to 1.5  10 7 CFU/g. Within 172 randomly selected β-lactam-resistant bacteria, 44 resistant phenotypes were found and 31.4% were multidrug resistant. The majority (85%) of the isolates identified belonged to the Enterobacteriaceae family. The presence of the bla TEM gene was detected in 80.9% of the tested isolates. The results suggest that without thermal processing of the milk and good hygienic practices, cheese may act as a vehicle of transfer of β-lactam-resistant bacteria to the gastrointestinal tract of consumers.

In Mozambique, as in other developing countries, the sale of street food is a source of income for thousands of unemployed families. However, the safety of these types of foods is a serious problem, given their frequent association with food-borne outbreaks. The aim of this study was to assess the microbiological quality and safety of street food sold in the main streets and informal markets of Maputo, the capital of Mozambique. From 83 different vendors selling different types of foods, 83 samples of ready-to-eat (RTE) street food were analyzed. Mesophiles, Escherichia coli and total coliforms were used as quality and hygiene indicators. Listeria monocytogenes, Salmonella and coagulase positive staphylococci were used as food safety indicators. High proportions of unsatisfactory food samples were found in both traditional hot (76.7%) and cold (75%) foods. L. monocytogenes and Salmonella were tested negative in this survey. However, when coagulase positive staphylococci was used as a food safety indicator, approximately 25% (23/83) of the food samples analyzed were classified as unsatisfactory/potentially hazardous. These results, showing that street food sold in Maputo clearly requires adequate sanitary conditions for its preparation and sale, contribute to the development of good manufacturing practices (GMP) for street food in Maputo, Mozambique. This is the first report on the microbiological quality and safety of street food in Mozambique.

Multiplex-PCR (MPCR) serogrouping and pulsed-field gel electrophoresis (PFGE) subtyping analysis are currently used by several public and private laboratories for the characterization of Listeria monocytogenes. In this study a set of 80 L. monocytogenes isolates belonging to the twelve serovars was used to investigate (i) the typeability of the rare serovars, (ii) the ability of PFGE analysis with ApaI and AscI to differentiate serovars within MPCR serogroups and (iii) the association of molecular types with the specific source or geographical origin of the isolates. With the exception of three isolates (rare serovars 4a and 4c) that were not amenable to restriction with ApaI, all the other analyzed isolates were subtyped by both enzymes. PFGE discriminated the 80 isolates into 62 combined ApaI and AscI PFGE patterns (pulsotypes), but could not differentiate serovars within MPCR serogroups, in which isolates from different serovars displaying the same pulsotype were found. Clustering analysis suggests that for some pulsotypes grouping according to Portuguese origin or source can be suggested. On the other hand, some L. monocytogenes clones are widely distributed. Two pulsotypes from Portuguese human isolates were identical to the ones displayed by human outbreak clones in the UK and in the USA and Switzerland, respectively, although they were not temporally matched. Computer-assisted data analysis of large and diverse PFGE type databases will improve the correct interpretation of subtyping data in epidemiological studies and in tracing routes and sources of contamination in the food industry.