Physical and Biological Treatments to Inactivate Food Spoiling Bacillus Subtilis

Abstract

Bacillus subtilis, also known as the hay bacillus or grass bacillus, is a Gram-positive, a member of the genus Bacillus. It is rod shaped and has the ability to form tough protective endospores allowing the organism to tolerate extreme environmental conditions, it is an obligate aerobe. Its ability to produce endospores has made the organism popular in the field of thermo bacteriology also. In commercial food processing protocols, heat inactivation studies play a vital role in the optimization of thermal processes, which are critical control points, often striking a balance between safety, organoleptic and nutritional acceptability of foods, therefore spoilage by this bacterium in food processing units in still a major concern. While B. subtilis is not a major agent of food spoilage or food-borne disease, this organism is a model spore former and one that is genetically tractable, with many strains available with mutations and reporter genes that can facilitate analysis of its resistance to the food production environment. The organism has the similar characteristics with B.cereus which is reported to cause outbreaks due to its ability to produce toxins resulting in types of illness: one type characterized by diarrhea and the other, called emetic toxin, by nausea and vomiting. Therefore to control the intrinsic or extrinsic entry of pathogens to the food processing units, there is a need to check the efficacy of various biological/ physical methods which can limit the growth of the B.subtilis. For this, various physical treatments (pH, temperature, UV radiation and microwave rations) and biological (lactic acid bacteria (LAB) and plant herbs) were evaluated for their anti-bacillus action so that a combination of technique could be developed against the proliferation of this bacteria. Among the factors listed above, the biological treatments seemed to be most economic and promising as antibacterial action was observed in case of application of LAB and clove, fennel.