This study was performed to determine the thermal resistance of L. monocytogenes at different heat treatments in İnegöl meatballs. İnegöl meatballs were divided into three groups. In group I, meatballs were inoculated with 8.0x102, 1.9x103, 6.0x103 and 2.4x104 cfu/g L. monocytogenes and then they were cooked at an internal temperature of 85 °C for 4 min. Group II meatballs were inoculated with 1.0x102, 2.0x102, 8.0x102, 5.6x105 and 2.0x106 cfu/g L. monocytogenes and cooked at an internal temperature of 80 °C for 4 min. In group III, the meatballs were inoculated with 5.6x105 and 2.0x106 cfu/g L. monocytogenes and cooked at an internal temperature of 63 °C for 30 min. In groups I and II, L. monocytogenes was not determined by direct plating method after cooking process. However, heat injured bacteria were recovered by an enrichment procedure when they were cooked at an internal temperature of 80 °C for 4 min. In group III, L. monocytogenes numbers were reduced by about 3 log cfu/g at 63 °C for 30 min. As a result, it was considered that the cooking process at an internal temperature of 85 °C for 4 min of İnegöl meatballs is sufficient for eliminating L. monocytogenes when it is at =105 cfu/g) of L. monocytogenes, and the meatballs may constitute a risk for foodborne listeriosis, especially in susceptible human hosts.

This study was performed to determine the thermal resistance of L. monocytogenes at different heat treatments in İnegöl meatballs. İnegöl meatballs were divided into three groups. In group I, meatballs were inoculated with 8.0x102, 1.9x103, 6.0x103 and 2.4x104 cfu/g L. monocytogenes and then they were cooked at an internal temperature of 85 °C for 4 min. Group II meatballs were inoculated with 1.0x102, 2.0x102, 8.0x102, 5.6x105 and 2.0x106 cfu/g L. monocytogenes and cooked at an internal temperature of 80 °C for 4 min. In group III, the meatballs were inoculated with 5.6x105 and 2.0x106 cfu/g L. monocytogenes and cooked at an internal temperature of 63 °C for 30 min. In groups I and II, L. monocytogenes was not determined by direct plating method after cooking process. However, heat injured bacteria were recovered by an enrichment procedure when they were cooked at an internal temperature of 80 °C for 4 min. In group III, L. monocytogenes numbers were reduced by about 3 log cfu/g at 63 °C for 30 min. As a result, it was considered that the cooking process at an internal temperature of 85 °C for 4 min of İnegöl meatballs is sufficient for eliminating L. monocytogenes when it is at =105 cfu/g) of L. monocytogenes, and the meatballs may constitute a risk for foodborne listeriosis, especially in susceptible human hosts.