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Growth Kinetics of a Native Toxigenic Isolate of Bacillus Cereus under the Influence of Incubation Temperature, pH and Sodium Chloride in Broth System

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Title Growth Kinetics of a Native Toxigenic Isolate of
Bacillus Cereus under the Influence of
Incubation Temperature, pH and Sodium
Chloride in Broth System
 
Creator Desai, S. V.
Varadaraj, M. C.
 
Subject 02 Safety
 
Description Aims: The growth behavior of vegetative cells and spores of a native toxigenic food
isolate of Bacillus cereus CFR 1534 was studied under the influence of incubation
temperature, pH and sodium chloride.
Place and Duration of Study: The study was undertaken in the Department of Human
Resource Development, CSIR-Central Food Technological Research Institute, Mysore
570020, India. The duration of study was during the period October 2009 to February
2010.
Methodology: The experimental design was a central composite design (CCD) based on
3 factors and 5 levels. The factors for vegetative cells were incubation temperature (12-
48ºC), pH level (5.5-7.5) and sodium chloride (2-6%). With spores, the ranges of pH and
NaCl levels were the same, while incubation temperature range was 22 to 42ºC.
Results: Multiple regression analysis of experimental data relating to lag phase duration
(LPD) and growth rate (GR) of B. cereus across the influencing factors in broth system revealed that LPD of vegetative cells and spores was primarily influenced by incubation
temperature. In vegetative cells of B. cereus, the LPD was in the range of 3.1 to 31.5 h
with the highest being observed at 48ºC and pH 6.5. The GR had the lowest of 0.2/h to
highest of 2.2/h at 30ºC and pH 7.5. With spores, the lowest LPD of 5.8 h was at 42ºC
and highest of 20.5 h at 22ºC and that of GR was in the range of 0.2/h at 22ºC to 0.7/h at
32ºC. Experimental tubes of vegetative cells with GR estimates of 1.3/h and above
revealed positive reactions for toxigenic traits of haemolytic and lecithinase activities
associated with B. cereus.
Conclusion: In the case of vegetative cells, incubation temperature in the range of 12-
20ºC resulted in higher LPD, while in spores, higher LPD was observed with incubation
temperatures of 22-26ºC. This could provide a basis to design protocols for a safe food in
the food chain.
 
Date 2014
 
Type Article
PeerReviewed
 
Format application/pdf
 
Language en
 
Rights —
 
Identifier http://ir.cftri.com/12383/1/British%20Microbiology%20Research%20Journal%204%2811%29%201267-1284%2C%202014.pdf
Desai, S. V. and Varadaraj, M. C. (2014) Growth Kinetics of a Native Toxigenic Isolate of Bacillus Cereus under the Influence of Incubation Temperature, pH and Sodium Chloride in Broth System. British Microbiology Research Journal, 4 (11). pp. 1267-1284.