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The aim of this study was to model the growth and survival behaviour of Salmonella Reading and endogenous lactic acid bacteria on fresh pre-cut iceberg lettuce stored under modified atmosphere packaging for 10 days at different temperatures (4, 8 and 15 &deg, C). The Baranyi and Weibull models were satisfactorily fitted to describe microbial growth and survival behaviour, respectively. Results indicated that lactic acid bacteria (LAB) could grow at all storage temperatures, while S. Reading grew only at 15 &deg, C. Specific growth rate values (&mu, max) for LAB ranged between 0.080 and 0.168 h&minus, 1 corresponding to the temperatures 4 and 15 &deg, C while for S. Reading at 15 &deg, C, &mu, max = 0.056 h&minus, 1. This result was compared with published predictive microbiology models for other Salmonella serovars in leafy greens, revealing that predictions from specific models could be valid for such a temperature, provided they were developed specifically in lettuce regardless of the type of serovars inoculated. The parameter delta obtained from the Weibull model for the pathogen was found to be 16.03 and 18.81 for 4 and 8 &deg, C, respectively, indicating that the pathogen underwent larger reduction levels at lower temperatures (2.8 log10 decrease at 4 &deg, C). These data suggest that this Salmonella serovar is especially sensitive to low temperatures, under the assayed conditions, while showcasing that a correct refrigeration could be an effective measure to control microbial risk in commercial packaged lettuce. Finally, the microbiological data and models from this study will be useful to consider more specifically the behaviour of S. Reading during transport and storage of fresh-cut lettuce, elucidating the contribution of this serovar to the risk by Salmonella in leafy green products.

This study was aimed at characterizing microbiologically Gilthead sea bream (Sparus aurata) and Sea bass (Dicentrarchus labrax) produced in two estuarine ecosystems in Andalusia (Spain): the estuary of the river Guadalquivir (La Puebla del Rio, Sevilla) (A), and the estuary of the river Guadiana (Ayamonte, Huelva) (B). The collected fish individuals and water were analysed for hygiene indicator microorganisms and pathogens. The statistical analysis of results revealed that microbial counts for the different microbiological parameters were not statistically different for fish type. On the contrary, considering anatomic part, viscera showed significantly higher concentrations for Enterobacteriaceae, total coliforms and for Staphylococcus spp. coagulase +. Furthermore, location A showed in water and fish higher levels for lactic acid bacteria, aerobic mesophilic bacteria, Enterobacteriaceae, total coliforms and Staphylococcus spp. coagulase +. Neither Listeria monocytogenes, nor Salmonella spp. were detected, though Vibrio parahaemolyticus was identified, molecularly, in estuarine water in location B. The predictive analysis demonstrated that the initial microbiological quality could have an impact on product shelf-life, being longer for location B, with better microbiological quality. Results stress the relevance of preventing the microbiological contamination of water in estuary production systems in order to assure the quality and safety of Gilthead sea bream and Sea bass.