Study of the microbiological quality, prevalence of foodborne pathogens and product shelf-life of Gilthead sea bream (Sparus aurata) and Sea bass (Dicentrarchus labrax) from aquaculture in estuarine ecosystems of Andalusia (Spain)
FOOD MICROBIOLOGY
Authors: Peres Costa, Jean Carlos Correia; Floriano, Belen; Bascon Villegas, Isabel Maria; Pablo Rodriguez-Ruiz, Juan; Denisse Posada-Izquierdo, Guiomar; Zurera, Gonzalo; Perez-Rodriguez, Fernando
Abstract
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.
Effect of a Lactobacillus sakei and Staphylococcus xylosus protective culture on Listeria monocytogenes growth and quality traits of Italian fresh sausage (salsiccia) stored at abusive temperature
ITALIAN JOURNAL OF ANIMAL SCIENCE
Authors: Pedonese, Francesca; Torracca, Beatrice; Mancini, Simone; Pisano, Sonia; Turchi, Barbara; Cerri, Domenico; Nuvoloni, Roberta
Abstract
Fresh sausages are not always thoroughly cooked before consumption and can support the growth of pathogenic microorganisms, especially when stored at incorrect temperatures. The aim of this study was to verify the growth of Listeria monocytogenes in Italian salsiccia stored at 2 degrees C, 7 degrees C and 12 degrees C for 9 days (t9) with (PC+) and without (PC-) a commercial protective culture (Lactobacillus sakei and Staphylococcus xylosus). L. monocytogenes PC + counts were statistically different from PC-, after 7 days (t7) at 7 degrees C and at 12 degrees C. At 2 degrees C, they increased in PC + by 0.03 and 0.36 log CFU/g vs. 0.25 and 0.91 in PC-, at t7 and t9. Moreover, quality characteristics (total aerobic counts, colour parameters, TBARS values, pH, sensory attributes) were assessed in fresh sausages stored at 7 degrees C. Significant differences were obtained in PC + samples at t7 for Pseudomonadaceae and Enterobacteriaceae (about 2 log CFU/g). Yeasts and moulds and Brochothrix thermosphacta were also significantly lower in PC + samples. PC + samples were more acidic than PC-, with statistically different colour parameters values particularly at the external surface; raw sausages resulted sensorially discernible at t7, whereas PC + and PC- cooked samples did not show any significant sensory difference. The studied protective culture proved to be a useful tool to increase safety and microbiological quality of salsiccia at abusive storage temperature, effectively limiting the growth of L. monocytogenes and Gram negative spoilage microorganisms, with some sensory drawbacks, especially at the end of the shelf life.