Heat inactivation of Listeria monocytogenes and Salmonella enterica serovar Typhi in a typical bologna matrix during an industrial cooking-cooling cycle.
The heat resistance of Salmonella enterica serovar Typhi PF-724 and Listeria monocytogenes 2812 was determined in a commercial bologna batter. The heat inactivation of the two bacterial species was also studied in a semiautomatic pilot smokehouse under cooking conditions that reproduced an industrial bologna process. S. enterica serovar Typhi PF-724 was less heat resistant than L. monocytogenes 2812. The D-values (times required to reduce the population by 1 logarithmic cycle) for S. enterica serovar Typhi PF-724 ranged from 10.11 to 0.04 min for temperatures of 50 to 70 degrees C, while for L. monocytogenes 2812, the D-values were 2.5-, 4.9-, 3.8-, 3.3-, and 2-fold higher at 50, 55, 60, 65, and 70 degrees C, respectively, than for S. enterica serovar Typhi PF-724. However, the z-value (temperature required to reduce log D by 1 logarithmic cycle) for S. enterica serovar Typhi PF-724 (5.72 degrees C) was not significantly different from the z-value for L. monocytogenes 2812 (7.04 degrees C), indicating that a given increase in temperature would have a similar effect on the decimal reduction time for both bacterial species in that meat emulsion. Our data on experimentally inoculated batter also showed that processing bologna at a cooking-cooling cycle commonly used in the industry resulted in a minimum 5-log reduction for both S. enterica serovar Typhi PF-724 and L. monocytogenes 2812.
Sallami
Lamjed
L
Food Research and Development Centre, Agriculture and Agri-Food Canada, 3600 Casavant Boulevard West, Saint-Hyacinthe, Quebec, Canada J2S 8E3.
Marcotte
Michèle
M
Naim
Fadia
F
Ouattara
Blaise
B
Leblanc
Claude
C
Saucier
Linda
L
D015169:Colony Count, Microbial; D003257:Consumer Product Safety; D005511:Food Handling / Q000379:methods*; D005516:Food Microbiology; D006801:Humans; D008089:Listeria monocytogenes / Q000254:growth & development*; D008461:Meat Products / Q000382:microbiology*; D012485:Salmonella typhi / Q000254:growth & development*; D013696:Temperature; D013997:Time Factors