Effect of heat activation and inactivation conditions on germination and thermal resistance parameters of Bacillus cereus spores.
The effect of isothermal and non-isothermal heat activation on germination and thermoresistance of two strains of Bacillus cereus spores was studied. Results indicated that the germination after isothermal activation was lower than after non-isothermal heating. The activation rate affected the z value, which increased with faster heating rates. For each temperature and inactivation rate, the non-isothermal activation at rate of 2 degrees C/min resulted in larger D values (D90 = 4.70 min) than isothermal activation (D90 = 4.04 min). The two mathematical equations used to analyse non-isothermal data produced similar predicted D and z values, nevertheless the Hayakawa equation modified in this work for non-linear regression analysis, requires less computational effort.
Instituto de Agroquímica y Tecnología de Alimentos (CSIC), Burjassot, Valencia, Spain.
A
A
Fernández
M J
MJ
Ocio
P S
PS
Fernández
A
A
Martínez
D001409:Bacillus cereus / Q000502:physiology*; D015169:Colony Count, Microbial; D006358:Hot Temperature; D008954:Models, Biological; D013171:Spores, Bacterial / Q000502:physiology; D013997:Time Factors