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.
, L. , Foulquie , M.R. & Revets , H. ( 2003 ). Screening for enterocins and detection of hemolysin and vancomycin resistance in Enterococci of different origins . Int. J. Food Microbiol. , 84 , 299 – 318
Authors:A. Mühlhansová, N. Zhexenbay, A. Kozybayev, Š. Horáčková, K. Solichová, and M. Plocková
, V. , FERNÁNDEZ , M. , CUESTA , I. , ALVAREZ , M. ( 2010 ): Quantitative detection and identification of tyramineproducing enterococci and lactobacilli in cheese by multiplex qPCR . Food Microbiol. , 27 , 933 – 939