Detection of Enterotoxigenic Genes in Food Isolates of Staphylococci

Soumya, Radhakrishnan (2009) Detection of Enterotoxigenic Genes in Food Isolates of Staphylococci. [Student Project Report]

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Abstract

This Dissertation / Report is the outcome of investigation carried out by the creator(s) / author(s) at the department/division of Central Food Technological Research Institute (CFTRI), Mysore mentioned below in this page.

Item Type:	Student Project Report
Additional Information:	Staphylococcal food poisoning is of major concern in public health programs worldwide. In India, the incidences are highly common and the losses are unaccounted, because of the absence of any systematic documentation. Increased food safety awareness among consumers offers new challenge to control the spoilage and pathogenic organisms in food. The detection of pathogenic organisms in food is of great importance to ensure well being of human kind. World Health Organization also emphasizes on more systemic and aggressive approach to significantly reduce the risk of microbiological food borne diseases. Efficient and rapid detection tools in combination with proper HACCP programmes can help in reducing the risk of food-borne diseases. In present investigation the 9 isolates of Staphylococci (excluding ATCC culture of S. aureus and S. epidermidis) from various food samples have been taken for biochemical tests. Biochemical tests include Gram staining, catalase test, phosphatase test, nitrate test, urease test, sugar fermentation test, DNase test, Antibiotic sensitivity test etc.Other than ATCC cultures, in the remaining 9 isolate 2 were identified as S. aureus, 2 were identified as S. xylosus, 2 were identified as S .cohnii, 1 isolate each of S. intermedius, S. galinarum and S. haemolyticus . These results clearly showed that S. aureus and S. xylosus were predominant among the different isolates in food samples. 80 Out of 9 natural isolates of Staphylococci ;4 isolates and also ATCC culture of S. aureus and S .epidermidis were subjected to PCR with sarA and agr set of primers. The presence of sarA and agr encoding element provides a fair indication of the enterotoxigenic potential in Staphylococci.sarA and agr positive isolate (SA30) when tested for the presence of entC and entD gene, gave positive result, which indicates that these sarA and agr positive isolates are enterotoxigenic. In future targeting other regulatory elements such as xpr or sae, could be approached for the detection of potentially toxigenic strains of Staphylococci. Further, work is needed to establish enterotoxigenic potential using other enterotoxins among classical (SEG to SEJ) or the new types (SEK to SER and SEU) genes reported in literature. Quantification of level of Staphylococci contamination and detection of toxins produced by them using nucleic acid based methods holds a promise. Further application of these techniques for the direct detection and quantification of bacteria in food samples will help in reducing the incidences of food poisoning in food chain establishment.
Uncontrolled Keywords:	Food-borne diseases Staphylococcus aureus enterotoxigenic food isolates
Subjects:	600 Technology > 08 Food technology > 29 Microbiological food
Divisions:	Human Resource Development
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	23 Sep 2009 07:09
Last Modified:	28 Dec 2011 10:11
URI:	http://ir.cftri.res.in/id/eprint/9197

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