Biocontrol of ochratoxigenic moulds (Aspergillus ochraceus and Penicillium nordicum) by Debaryomyces hansenii and Saccharomycopsis fibuligera during speck production

Speck is a meat product obtained from the deboned leg of pork that is salted, smoked and seasoned for four to six months. During speck seasoning, Eurotium rubrum and Penicillium solitum grow on the surface and collaborate with other moulds and tissue enzymes to produce the typical aroma. Both of these strains usually predominate over other moulds. However, moulds producing ochratoxins, such as Aspergillus ochraceus and Penicillium nordicum, can also co-grow on speck and produce ochratoxin A (OTA). Consequently, speck could represent a potential health risk for consumers. Because A. ochraceus and P. nordicum could represent a problem for artisanal speck production, the aim of this study was to inhibit these mould strains using Debaryomyces hansenii and Saccharomycopsis fibuligera. Six D. hansenii and six S. fibuligera strains were tested in vitro to inhibit A. ochraceus and P. nordicum. The D. hansenii DIAL 1 and S. fibuligera DIAL 3 strains demonstrated the highest inhibitory activity and were selected for in vivo tests. The strains were co-inoculated on fresh meat cuts for speck production with both of the OTA-producing moulds prior to drying and seasoning. At the end of seasoning (six months), OTA was not detected in the speck treated with both yeast strains. Because the yeasts did not adversely affect the speck odour or flavour, the strains are proposed as starters for the inhibition of ochratoxigenic moulds

Use of bio-protective cultures to improve the shelf-life and the sensorial characteristics of commercial hamburgers

The use of mixtures of bio-protective cultures, like Lactobacillus sakei subsp. carnosus/L sakei + Staphylococcus xylosus (1/1 ratio), Lactococcus lactis spp. lactis/L sakei + S. xylosus (1/1 ratio), and L sakei subsp. carnosus/L. sakei + S. xylosus (1/2 ratio), inoculated in beef hamburger packaged in modified atmosphere and stored at 4 +/- 2 degrees C, determined a better microbiological and chemical-physical quality of the products. In particular, they inhibited the growth of Brochothrix thermosphacta resulting in no white slime on the products as well as they determined a low concentration of total volatile basic nitrogen (TVB-N). Moreover, the bio-protective cultures influenced the flavour and the odour of the hamburgers. For this reason, the shelf life of the products added with starter cultures could be extended up to 12 day

Sous vide cook-chill mussel (Mytilus galloprovincialis): Evaluation of chemical, microbiological and sensory quality during chilled storage (3 °C)

Abstract The changes in the chemical, physical, microbiological and sensory qualities of sous vide cooked processed mussels in comparison with conventional cooked mussels (90°C-10 min) were monitored during chilled storage (3.0 ± 1 °C). The sous vide cook and chill method at 85 °C for 10 min with or without salt brine resulted in being able to preserve the quality of mussels and extend their shelf-life to 21 storage days. Moreover, with the addition of brine a shelf-life extension of up to 30 days was possible, in comparison to mussels subjected to conventional cooking. The use of brine, other then facilitating packaging procedures preventing micro ruptures, showed a positive effect on moisture content (81.4 vs 73.5%), TVB-N (10.4 vs 16.7 mg N/100 g), reduced bacterial growth and sensory attributes, such as meat turgidity of mussels. Mussels processed by " sous vide cook and chill" method, marketed at refrigerated conditions, may be a promising addition to "ready to eat" and "ready to cook" food products with an extended shelf-life and high versatility as requested by the changes in consumer habits

A case of spoilage in wurstel sold in an Italian supermarket

In the current study, the shelf-life and the spoilage of Italian wurstel sold in a local supermarket was investigated. The analysis included identifying the causative microorganisms and the variations in physical-chemical parameters (pH, aW, lactic acid, and ammonia). The spoilage consisted of a white surface coating or slime that appeared after the thirtieth day of storage. The cause of the spoilage was the uncontrolled growth of thermoduric heterofermentative lactic acid bacteria (LAB) that occurred during storage. The LAB, including Leuconostocs and Brochothrix thermosphacta organisms, can survived the pasteurisation process. Due to the deacidifying action of B.thermosphacta and the production of ammonia, there was no evidence of off-odour or off-flavour and no change in pH. Furthermore, no loss of the vacuum seal was observed in the spoiled wurstel