The pH of a product is related to the acidity or alkalinity of the product.For example, psychrotrophs such as Listeria monocytogenes grow at refrigeration temperature (4☌ or 39☏), while thermotrophs can grow at higher temperatures (45☌ or 113☏). The temperature values for microbial growth depend on the type of microorganism.The most important factors that affect microbial growth are: Most foods contain sufficient nutrients to support microbial growth. Cross-contamination of food products spread from processing environment due to poor/improper sanitationįactors affecting the growth of microorganisms in foods.human contamination due to poor personal hygiene (skin, clothing, especially hands), faecal contamination, failure in infection control (illness not reported).soil and water contaminated by non-treated manure.The major sources of biological contaminants in food are: These include: Clostridium botulinum, Bacillus cereus, and Staphylococcus aureus. The risk of intoxication is prevented by controlling the growth of toxin producing bacteria. They survive normal cooking temperatures and even temperatures higher than 80☌ (176☏). These toxins are very difficult to eliminate. Examples of spore forming bacteria include Bacillus cereus, Clostridium botulinum and Clostridium perfringens.īacteria must first grow in the food before producing toxins. For example, steam cooking significantly reduces non-spore-forming food borne pathogens, but only inactivates spores. However, some bacteria that produce spores can survive cooking temperatures. Infection can be prevented by properly processing and handling food products because pathogens are easily destroyed by heat. Intoxication occurs when bacteria produce toxins that affect the body. Infection occurs when organisms invade the host and multiply in the body. These organisms can affect human health, including infection, intoxication and even death. Parasites (ex: Toxoplasma gondii, Cryptosporidia, Giardia spp., Trichinella spiralis, Taenia solium, Anisakis spp.). Virus (ex: hepatitis A virus, Norwalk viruses, Rotavirus)., Enterohaemorrhagic Escherichia coli, Campylobacter jejuni, Yersinia enterocolitica, Listeria monocytogenes, Bacillus anthracis, Bacillus cereus, Staphlococcus aureus, Clostridium botulinum, Clostridium perfringens, Vibrio vulnificus, Vibrio parahaemolyticus) Factors Affecting the Growth of Microorganisms in Foods.They are a major concern in food processing because they cause most food borne illness outbreaks. All rights reserved.Biological hazards are organisms, or substances produced by organisms, that pose a threat to human health. This extensively-documented survey of the species that cause non-stability at 55 ☌ in LACF will help canneries to improve the management of microbial contamination.Ĭopyright © 2013 Elsevier B.V. Taken together, our results single out the species most suitable for use as indicators for thermal process settings. The spore heat resistance parameters (D or δ and z values) from 36 strains isolated in this study were determined. vegetables, ready-made meals containing meat, seafood or other recipes, products containing fatty duck, and related to the intensity of the thermal treatment applied in these food categories. Species frequency was dependent on food category, i.e. The other most frequent bacterial genera identified were Bacillus, Thermoanaerobacter, Caldanaerobius, Anoxybacillus, Paenibacillus and Clostridium. Three genera were responsible for more than 80% of all non-stability cases: mostly Moorella (36%) and Geobacillus (35%), and less frequently Thermoanaerobacterium (10%). A single species was identified for 93% of examined samples. Bacteria were identified by microsequencing or a recent developed tool for group-specific PCR detection (SporeTraQ™). In this study we identified the bacterial species responsible for non-stability after prolonged at 55 ☌ of incubation of LACF from 455 samples collected from 122 French canneries over 10 years. LACF are also often submitted to additional incubation conditions, typically 55 ☌ for 7 days, to monitor spoilage by thermophiles. Good Manufacturing Hygienic Practices include stability tests for managing the pathogen risk related to surviving mesophilic bacterial spores. Thermal processing of Low Acid Canned Foods (LACF), which are safe and shelf-stable at ambient temperature for several years, results in heat inactivation of all vegetative microorganisms and the partial or total inactivation of spores.
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