Authors:M. López, L. M. Medina, R. Huerta, and R. Jordano
The aim of this work was to study in six different types of European dry-sausages (of the Mediterranean area) the ocurrence of contaminant biota: enterobacteria, coliforms, E. coli, enterococci, sulphite-reducing clostridia, Salmonella-Shigella and Listeria monocytogenes, in the course of the ripening process. A total of 162 samples were analysed at different stages of the elaboration process. These were grouped in eighteen lots, three for each type of dry-sausages. Throughout the ripening process a decrease in some microbe groups (enterobacteria, coliforms, E. coli) occurred in all cases. Yeasts and enterococci remained the same or even increased in number. We have also confirmed the presence of Salmonella, sulphite-reducing clostridia and Listeria in some samples of unripened product. Consequently, an improvement could be desirable in the hygienic quality of the raw material of dry-sausages. Nevertheless, the final products analysed showed an acceptable state of food safety in all cases.
Authors:M. G. Córdoba, J. J. Córdoba, and R. Jordano
In the commercial processing of croquettes a 80 °C heat treatment for 30 min is applied to the raw materials to make a semi-solid paste called „bechamel”. Since the heat treatment is not that of sterilization, some micro-organisms surviving it may proliferate in the next steps, which could introduce two microbial hazards; the presence of pathogenic bacteria and croquettes spoilage. To evaluate microbiological hazards, microbiological analysis of the bechamel cooled and stored under refrigeration following commercial processing were developed at different times of cooling. In addition a fast cooling method was assayed. Immediately after heat treatment used to obtain the bechamel, microbial counts were always under 1 log CFU g-1, except for mesophilic aerobes which were at least of 1.2 log CFU g-1. During cooling used in commercial process of croquettes, levels of most micro-organisms investigated showed high increases as compared with behamel after cooking. In this step mesophilic organisms, psychotropic organisms and yeast reached levels of around 6 log CFU g-1. Enterococci counts increased during cool storage, although always were at levels below 3.2 log CFU g-1.EnterobacteriaceaeandClostridiumsp. only slightly increased at the end of cold storage reaching levels of around 3 log CFU g-1. Although rates which could be considered as being inadmissible were reached at day 5, the use of over 1-day old bechamel could be associated with microbiological sanitary hazards or with the spoilage of the croquettes made afterwards. In contrast, the bechamel cooled at -20 °C air temperature for 12 h, only showed total aerobic counts of under 1 log CFU g-1. Cooling of bechamel is a decisive critical control point and a fast cooling should be considered in the implementation of an HACCP program in the prepared and frozen croquettes process.
Authors:M. V. Rodriguez, L. M. Medina, and R. Jordano
The effect of three different modified atmospheres on the shelf-life of sponge cake was studied. Three packaging atmospheres were tested: 50% CO2: 50% N2, 100% CO2, and standard air as control. The samples were examined daily for visible mould growth and analysed periodically (after 2, 6, 13, 22 and 27 days) throughout storage (15–20 °C and 51–63% RH) for gaseous composition and microbial populations: mesophilic aerobic and anaerobic bacteria, lactic acid bacteria (LAB) and yeasts and moulds. The atmosphere CO2:N2 (50:50) extended the shelf-life of the sponge cakes by 2–3 days with respect to packaging in standard air.
Authors:M. Reiter, H. Volkmann, U. Imianovsky, M. Lopez, L. Medina, and R. Jordano
The incidence of Listeria monocytogenes in refrigerated and frozen chicken parts was investigated, using the Mini-Vidas™ system (bioMérieux). Two hundred and eigthy chicken parts were tested: 40 skin samples from the breast and leg, 120 samples from refrigerated wings, breasts and legs and 120 samples from frozen wings, breasts and legs (40 of each). The 219 samples tested positive (78.21%). The parts with the highest incidence were frozen breasts (100%) and wings (95%). In frozen legs, the values were lower (60%). In refrigerated parts, the incidence was higher in breasts (85%) and in wings (80%). In legs samples, similarly to the frozen ones, the incidence was lower (50%). In the skin of the breasts and legs, the incidence was 77.50%. Statistical evaluation demonstrated that there are no differences between frozen breasts and wings but there are differences between similar refrigerated parts. The refrigerated and frozen legs are the only parts that are statistically equal. The percentages that were detected show the importance of requiring the absence of Listeria spp. in chickens.
Authors:M. C. Lopez, L. M. Medina, M. J. Linares, and R. Jordano
The evolution in counts of yeasts from six lots of different dry-sausages produced in three European Union (EU) countries (France, Italy and Spain) is tested. Each lot was analyzed in three phases of their production: fresh product, first staged drying and final product. Three samples were analyzed in each test. Counts of yeasts during the ripening process showed an irregular evolution. Regarding the species isolated, the most frequent ones belonged to genera Candida (C. albicans, C. famata, C. guillermondii, C. krusei, C. parapsilosis, C. stellatoidea, C. zeylanoides.), Trichosporon (T. capitatum, T. beigelli), Rhodotorula and Geotrichum (G. candidum).