TABLE OF CONTENT
Table of content
Introduction and Literature Review
Aims and Objective
Sterilization of Equipment
Laboratory Preparation of
Processing of Sample
Enumeration of Bacillus Cereus from
Food Sample using Most Probable Number (MPN)
Culturing of Bacillus Cereus
INTRODUCTION AND LITERATURE REVIEW
B. Cereus is a spore forming organism capable of developing at a whole range of temperature, PH and water activity values. (Barker et al; 2005) thus bacterium, frequency associated with food born disease can be found in the natural environment and isolated from various foods, including meat and meat production (Ahmed et al; 1983).
Some of the enterotoxins produced by B. Cereus causes food born diarrhea, characterized as the “diarrheic syndrome” this syndrome can be associated with the productin of five different protein, haemolysine, enterotoxin and enteroxins, non haemolytic enteroxine cytotoxins, the symptoms last for a period of 12 to 24 hours and consist of abnormal pain, watery diarrhoea and nausea. It is believed that the enterotoxins are mostly produced in the small intestine of the individual (Ankolekar et al; 2009) food associated with outbreaks of B cereus diarrhoea fr4equency include protein rich foods and researcher’s have emphasized the importance of the presence of microorganism or its spores in meat and meat products for the occurrence of such outbreaks practices such as inadequate temperature during food processing are indicated as the main factors contributing to the spread of the microorganism in these foods, with the objective of investigating the growth of enterotoxin producing B. Cereus in processed meat, this study was carried out using cultures of the microorganism from different origin (Bernhard et al; 1978) it is frequently isolated from milk and dairy products (Ahmed et al 1983) in milk B. Cereus causes a defect known as “bitty” cream or sweet curding. It is found in rice, rice products oriental dishes and ingredients (Blaky et al; 1980) a variety of foods have been implicated in food-poisoning (Johnson, 1984) frequently isolated from soil and growing plants in the intestinal track of insect and mammals (Arnesen et al; 2008)
Germination of most of the enterotoxigenic strain of B. Cereus adhered to CaC0-2 cells is stimulated while another celline HEP-2 does not trigger germination (Wijnands et al, 2007). The germination stimulated by Cac0-2 cells is related to the normal functions of germination receptors (Horustra et al, 2009) Beta-lactamase type I occur in the sporalated for run in penicillin-resistant B Cereus (Fenselau et al, 2008)
B. Cereus is easily isolated and identified from samples clinical specimens and food samples are collected, stored temporary at refrigerating temperature and plated on selective agar media (Boschioits et al, 1983) low level of peptone and the absence of carbohydrates in KG medium facilitated formation of spore (Johnson, 1984). A columbia base 5% blood agar surface-spread with polymyxin B is recommended by Kramer et al. (Kramer et l, 1982) for better colonly characteristic and colony types are easily differentiated for serological testing in enumeration by most probable number method, trypticase soy polymyxin broth is recommended.
Bacaragar is a modified selective agar and also contains Bacara and egg yolk. Pyruuate is found in rice, rice products, oriental dishes and ingredients (Blakey et. Al. 1980; et al, 1986). A variety of foods have been implicated in food-poisoning.
Emetic syndrome caused by bacillus cereus is highly associated with rice and rice products (Johnson, 1984).
Reauire both Gerl and area germination receptors for germination in inosine as the sole germinant, whereas the Gerl receptor is responsible for most of the response to L-alarine as the sole germinant, with a smaller contribution from identify with its homolog Gern which is a Na+/H+-K+ antiporter that is required for normal spore germination, while it has a significant role in outgrowth; gert mutant spores do not outgrow efficiently under alkaline conditions and outgrow more slowly than the wild type in the presence of high Nacl concentrations. The Gert protein in B. Cereus therefore countibutes to the success of spore outgrowth from the germinated state during alkaline or Na+ stress (senior et al, 2008).
Germination of most of the enterotoxigenic strains of B. cereus adhered to caco-2 cells is stimulated while another celline, Hep-2, does not trigger germination (wijnards et al; 2007). The germination stimulated receptors (Hornstra et al. 2009).
Beta-lactamase type I occurs in the sporulated from the in penicillin resistant B. cereus (fenselau et alp; 2008) B. cereus is easily isolated and identified from samples chemical; specimens and food samples are collected, stored temporary at refrigerating temperature if necessary, diluted if necessary, and plated on selective agar media.
Mami egg yolk polymyxin agar (MYP) is usually recommended, polymyxin is the selective agent, and egg yolk and mannitol are differential agents. Typical colonies are rough with.
B. Cereus is differentiated from other non motile species by forming diffuse growth on predried nutrient agar as B. Cereus Var. mycoides B.cereus is usually strong B-hemolytic on trypticase soy sheep blood agar plate, whereas, B. thuringiensis and B. cereusvar. Mycoides are often weakly hemolytic and B. anthracis is non motile and non hemolytic. Endotoxcin crystals are found in B. thuringiensis (Harmon, 1978). Other biochemical tests used in confirming B. cereus are: acid is produced from anaerobic glucose fermentation, nitrate reduction, VP positive, tyrosine, decomposition, selective growth on blood agar and bacara agar, Kramer etal, 1982) recommended the following biochemical test for confirmation of B. cereus: Glucose +, mannotol, Xyclose-. And arabinose-, serotyping is recommended by a number of investigators (Bernhard et al 1978).
B. anthracis and other Bacillus species including B.cereus can also be identified by the rapid apitests with the aid of computer programmes (Logan et al., 1985).