Thermal inactivation of Bacillus cereus and Clostridium perfringens vegetative cells and spores in pork luncheon roll.

The aim of this study was to design a thermal treatment(s) for pork luncheon roll, which would destroy Bacillus cereus and Clostridium perfringens vegetative cells and spores. B. cereus and C. perfringens vegetative and spore cocktails were used to inoculate luncheon meat. Samples were subjected to different temperatures and removal times. The decimal-reduction times (D-values) were calculated by linear regression analysis (D = -1/slope of a plot of log surviving cells versus time). The log(10) of the resulting D-values were plotted against their corresponding temperatures to calculate (-1/slope of the curve) the thermal resistance (z-values) of each cocktail. The D-values for vegetative cells ranged from 1 min (60 degrees C) to 33.2 min (50 degrees C) for B. cereus and from 0.9 min (65 degrees C) to 16.3 min (55 degrees C) for C. perfringens. The D-values for B. cereus spores ranged from 2.0 min (95 degrees C) to 32.1 min (85 degrees C) and from 2.2 min (100 degrees C) to 34.2 min (90 degrees C) for C. perfringens. The z-values were calculated to be 6.6 and 8.5 degrees C for B. cereus vegetative and spores, respectively, and 7.8 and 8.4 degrees C for C. perfringens vegetative cells and spores, respectively. The D-values of B. cereus and C. perfringens suggest that a mild cook of 70 degrees C for 12s and 1.3 min would achieve a 6 log reduction of B. cereus and C. perfringens vegetative cells, respectively. The equivalent reduction of B. cereus and C. perfringens spores would require the pork luncheon meat to be heated for 36 s at 105 and 110 degrees C, respectively. The results of this study provide the thermal inactivation data necessary to design a cooking protocol for pork luncheon roll that would inactivate B. cereus and C. perfringens vegetative cells and spores. The data may also be used in future risk assessment studies.

[1]  P. Fernández,et al.  Effect of heat activation and inactivation conditions on germination and thermal resistance parameters of Bacillus cereus spores. , 2001, International journal of food microbiology.

[2]  J. Gaze,et al.  Heat resistance of Bacillus cereus, Salmonella typhimurium and Lactobacillus delbrueckii in relation to pH and ethanol. , 2001, International journal of food microbiology.

[3]  M. G. Johnson,et al.  Inactivation of Salmonella and Listeria in ground chicken breast meat during thermal processing. , 1999, Journal of food protection.

[4]  B. S. Marmer,et al.  Thermal destruction of Escherichia coli O157:H7 in beef and chicken: determination of D- and z-values. , 1997, International journal of food microbiology.

[5]  H M Marks,et al.  Modeling non-linear survival curves to calculate thermal inactivation of salmonella in poultry of different fat levels. , 2001, International journal of food microbiology.

[6]  K. L. Brown,et al.  Control of bacterial spores. , 2000, British medical bulletin.

[7]  P. E. Granum,et al.  Bacillus cereus and its food poisoning toxins. , 1997, FEMS microbiology letters.

[8]  R. Beumer,et al.  Comparison of media for enumeration of Clostridium perfringens from foods. , 2003, Journal of microbiological methods.

[9]  K. Shinagawa.  Analytical methods for Bacillus cereus and other Bacillus species. , 1990, International journal of food microbiology.

[10]  P. Bodnaruk,et al.  Impact of cooking, cooling, and subsequent refrigeration on the growth or survival of Clostridium perfringens in cooked meat and poultry products. , 2003, Journal of food protection.

[11]  J. Sheridan,et al.  A rapid method of enumarating microorganisms from beef, using an acridine orange direct-count technique , 1989 .

[12]  R. Phebus,et al.  Effects of chilling rate on outgrowth of Clostridium perfringens spores in vacuum-packaged cooked beef and pork. , 2003, Journal of food protection.

[13]  I. Leguerinel,et al.  Effect of Water Activities of Heating and Recovery Media on Apparent Heat Resistance of Bacillus cereusSpores , 2001, Applied and Environmental Microbiology.

[14]  I. Leguerinel,et al.  Model for Combined Effects of Temperature, pH and Water Activity on Thermal Inactivation of Bacillus cereus Spores , 1998 .

[15]  F. Gavini,et al.  Injury and Lethality of Heat Treatment of Bacillus cereus Spores Suspended in Buffer and in Poultry Meat. , 1997, Journal of food protection.

[16]  S. Martínez,et al.  Thermal inactivation of Bacillus cereus spores formed at different temperatures. , 1999, International journal of food microbiology.

[17]  M. Sarker,et al.  Comparative Experiments To Examine the Effects of Heating on Vegetative Cells and Spores of Clostridium perfringens Isolates Carrying Plasmid Genes versus Chromosomal Enterotoxin Genes , 2000, Applied and Environmental Microbiology.

[18]  J. Lyng,et al.  Effect of radio frequency cooking on the texture, colour and sensory properties of a large diameter comminuted meat product. , 2004, Meat science.

[19]  B. S. Marmer,et al.  Thermal inactivation ofClostridium perfringensvegetative cells in ground beef and turkey as affected by sodium pyrophosphate , 1998 .

[20]  P. E. Granum,et al.  What problems does the food industry have with the spore-forming pathogens Bacillus cereus and Clostridium perfringens? , 1995, International journal of food microbiology.

[21]  C. Duncan,et al.  Improved medium for sporulation of Clostridium perfringens. , 1968, Applied microbiology.

[22]  F. Busta,et al.  Thermal inactivation kinetics of Bacillus subtilis spores suspended in buffer and in oils. , 1995, The Journal of applied bacteriology.

[23]  C. Vanderzant,et al.  Compendium of Methods for the Microbiological Examination of Foods , 1992 .

[24]  S. D. Elek,et al.  Experimental food-poisoning by Clostridium welchii. , 1957, Lancet.

[25]  S. Condón,et al.  Effects of several factors on the heat-shock-induced thermotolerance of Listeria monocytogenes , 1997, Applied and environmental microbiology.

[26]  I. Leguerinel,et al.  Modelling the influence of pH and organic acid types on thermal inactivation of Bacillus cereus spores. , 2001, International journal of food microbiology.

[27]  Frank F. Busta,et al.  Thermal Inactivation of Clostridium perfringens After Growth at Several Constant and Linearly Rising Temperatures , 1981 .

[28]  J. T. Peeler,et al.  Thermal inactivation of ileal loop-reactive Clostridium perfringens type A strains in phosphate buffer and beef gravy , 1977, Applied and environmental microbiology.

[29]  I. Leguerinel,et al.  Validation of an overall model describing the effect of three environmental factors on the apparent D-value of Bacillus cereus spores. , 2005, International journal of food microbiology.

[30]  A. Califano,et al.  Thermal inactivation of Escherichia coli O157:H7 and Escherichia coli isolated from morcilla as affected by composition of the product , 2003 .

[31]  Mercedes López,et al.  Effects of sporulation media and strain on thermal resistance of Bacillus cereus spores , 2007 .

[32]  B. McClane,et al.  Evidence That the Enterotoxin Gene Can Be Episomal in Clostridium perfringens Isolates Associated with Non-Food-Borne Human Gastrointestinal Diseases , 1998, Journal of Clinical Microbiology.

[33]  C. R. Stumbo,et al.  Thermobacteriology in Food Processing , 1973 .

[34]  J. Sheridan,et al.  Decontamination of pork carcasses during scalding and the prevention of Salmonella cross‐contamination , 2003, Journal of applied microbiology.

[35]  Lihan Huang,et al.  Increased thermotolerance of Clostridium perfringens spores following sublethal heat shock , 2003 .

[36]  J. Sofos,et al.  Control of foodborne microorganisms , 2001 .