Quality & Safety
Bacterial spores are among the most difficult to destroy in foods, being resistant to heat, radiation, chemicals, including disinfectants/sterilising agents, acids, dehydration, etc.. The group of spore-forming bacteria (Bacillus & Clostridium are the main genera) contains both spoilage and pathogenic organisms, the latter by production of some of the most powerful natural toxins known. Food poisoning is the result of ingestion of pre-formed toxin in food, or toxin production during growth in the GI tract. Spoilage of canned foods is either by production of acids alone (B. stearothermophilus in low acid foods) or vigorous gas and H2S production (as by clostridia). Several species of spore-formers cause animal and human infections, e.g. anthrax (B. anthracis), tetanus (C. tetani), gas gangrene (C. perfringens and some other species of clostridia), and severe infections of the skin and underlying muscles in cattle and sheep (e.g. C. septicum, C. oedematiens). The spoilage species cause problems in heat-treated foods, e.g.. pasteurised products and canned (‘fully heat processed’) products. There are also Bacillus species that can be very useful, e.g. insect pathogens that have been used as ‘biological pesticides’, some clostridia produce useful products from sugar metabolism, e.g.. propanol, butanol, acetone etc. In this webinar it is aimed to present a general overview of basic characteristics of sporeforming bacteria and their spores, diseases caused including examples of recent outbreaks, types of spoilage, isolation methods from foods as well as control measures.
Outbreaks; Spore bacteria; Pathogenic microorganisms
Prof. Paula Teixeira and Prof. Paul Gibbs
Portuguese Catholic University