Evaluation of the microbiological safety and sensory quality of a sliced cured-smoked pork product with protective cultures addition and modified atmosphere packaging.

The aim of this study was to evaluate the effect of two protective lactic acid bacteria cultures combined with modified atmosphere packaging on the survival/growth of Listeria innocua 2030c (as a surrogate for Listeria monocytogenes) and on sensory attributes of ready-to-eat 'lombo' over storage time. Sliced 'lombo', a traditional cured-smoked pork loin, was inoculated with L. innocua 2030c, Lactobacillus sakei ST153 (isolated from 'salpicão') and BLC35 culture (with Lactobacillus curvatus, Staphylococcus xylosus and Pediococcus acidilactici; CHR Hansen) as protective cultures. Samples were packed in two modified atmosphere packaging conditions (20% CO2/80% N2 and 40% CO2/60% N2) and stored at 5 ℃ for 124 days. Both cultures led to a reduction of 1-2 log CFU/g of L. innocua 2030c after 12 h; however, at the end of storage only Lb. sakei ST153 maintained this antilisterial effect, which was more evident at 40% CO2/60% N2. The influence of cultures addition and modified atmosphere packaging conditions on the sensory characteristics of the product were not significant. Thus, Lb. sakei ST153 combined with modified atmosphere packaging is a strong candidate to be used in a biopreservation strategy maintaining the traditional sensory quality of cured-smoked pork products and increasing their safety with respect to Listeria spp.

Use of molecular methods for the identification of yeast associated with table olives.

A molecular approach is used for the identification of yeast isolated from table olives. Our results validate those obtained in the past by the classical biochemical methodology. Yeast were isolated from both aerobically and anaerobically processed black table olives and also from canned seasoned green table olives. Molecular identification methodology used included restriction pattern analysis of both PCR-amplified 5.8S rRNA gene and internal transcribed spacers ITS(1) and ITS(2). For some species, sequence analysis of the 26S rRNA gene was necessary. These techniques allowed the identification of three yeast species (Issatchenkia occidentalis, Geotrichum candidum and Hanseniaspora guilliermondii) which had not been described previously in table olives. Saccharomyces cerevisiae and Candida boidinii were the most frequent species in green seasoned olives and processed black olives, respectively. The molecular study of total DNA variability among the S. cerevisiae strains isolated indicates a quite heterogeneous population, with at least four different restriction patterns.