![]() ![]() Different semifinal extracts are mixed according to their individual physicochemical and microbiological characteristics to a final product according to the requirements of the consumer. These extracts are subjected to harsh conditions during production and a final UHT treatment. The bacterial load is expected to be greatly reduced in semifinal gelatin extracts. Bacillus licheniformis, members of the Bacillus cereus group, Bacillus coagulans, Bacillus fumarioli, Bacillus badius, Bacillus subtilis, Brevibacillus agri, Alicyclobacillus acidocaldarius, and Paenibacillus cookii were found to be contaminants in a Belgian gelatin production process ( 6). The ubiquitous occurrence of these bacteria in combination with their wide nutritional versatility and wide pH and temperature ranges for the growth and formation of endospores, which are much more resistant to heat, chemicals, irradiation, and desiccation than vegetative forms ( 22), makes this group of bacteria an ever-present problem in different industries (see, e.g., references 3 and 10). In general, contamination of industrial plants and products with aerobe endosporeformers is a widespread problem. Nevertheless, quality control testing at gelatin-producing factories has indicated that thermotolerant, aerobic, endospore-forming bacteria may persist in the final product (Paul Stevens, personal communication). However, extreme temperature and pH conditions during the manufacture, ultrahigh-temperature (UHT) treatment, and drying of the gelatin extracts should guarantee the microbial sterility of the end product. In a previous study, contamination of a gelatin production process with a variety of gram-positive and gram-negative bacteria was reported ( 6). These raw materials are collected from slaughterhouses, butcher shops, or other plants dealing with animal raw materials. Skin and bones mainly of bovine or porcine origin are used for this purpose. Gelatin is a proteinaceous colloid and is extracted from animal connective tissue during a multistage process which involves, besides the actual extraction, a chemical treatment, purification, and drying of the extracts. ![]() ![]() The bacteriological quality of gelatin is of great importance, as it is applied for its gelling and stabilizing properties in the food industry (confectionery products, dairy products, etc.) and the pharmaceutical industry (hard and soft capsules, tablets, etc.) and in the production of photographic films, matches, glues, etc. These findings are of great concern with regard to the safety and quality of gelatin and its applications. Moreover, some of these species have known pathogenic properties. The majority of these species include strains exhibiting gelatinase activity. Representative strains were identified as Bacillus cereus, Bacillus coagulans, Bacillus fumarioli, Bacillus amyloliquefaciens, Bacillus licheniformis, Bacillus pumilus, Bacillus sonorensis, Bacillus subtilis, Bacillus gelatini, Bacillus thermoamylovorans, Anoxybacillus contaminans, Anoxybacillus flavithermus, Brevibacillus agri, Brevibacillus borstelensis, and Geobacillus stearothermophilus. The majority of isolates belonged to members of Bacillus or related endospore-forming genera. Representative strains were identified by means of 16S rRNA genesequencing, species-specific gyrB PCR, and gyrA and rpoB sequencing and were tested for gelatinase activity. For characterization and identification of the 1,129 bacterial isolates, repetitive-element PCR was used to obtain manageable groups. Each of these batches was suspected of having bacterial contamination based on quality control testing at the production plant from which it originated. In total, 1,129 isolates were obtained from a total of 73 gelatin batches originating from six different production plants. Since these extracts are subjected to harsh conditions during production and a final ultrahigh-temperature treatment, the bacterial load at this stage is expected to be greatly reduced. In this study, bacterial contamination of semifinal gelatin extracts from several production plants was examined. 25:611-618), contamination of a gelatin production process with a variety of gram-positive and gram-negative bacteria was demonstrated. Indeed, this animal colloid has many industrial applications, mainly in food and pharmaceutical products. Bacterial contamination of gelatin is of great concern. ![]()
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