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.