Survival of Campylobacter jejuni, Salmonella, and Listeria monocytogenes and Temperature Change in Low-Temperature-Longtime-Cooked Chicken Meat

Abstract: Low-temperature and longtime (LT-LT) cooking, also known as sous vide cooking, is the process in which meat is sealed in a bag and cooked in hot water at a relatively low temperature of around 60°C. This cooking method has increased in popularity, and low-temperature cookers for home use are now commercially available. However, after LT-LT cooking, if any foodborne bacteria remain, they could cause infection and foodborne illnesses. Therefore, in the present study, the aim was to determine the appropriate LT-LT cooking methods for chicken by assessing temperature changes and studying the bacteria in LT-LT-cooked chicken meat. At set cooking temperatures of 60 and 65°C, the temperatures were measured at the surface and in the centers of single- and double-layer samples of 300 g of chicken breast meat. The times required to reach 50°C were 5 to 14 min at the surface, 25 min in the center of the single-layer sample, and 33 to 35 min in the center of the double-layer sample. The time taken to reach 50°C was fastest in the surface of single-layer chicken meat, followed by the center of single-layer and double-layer chicken meat (P < 0.05). When the meat was LT-LT cooked at 60 and 65°C for 60 min, color changes in the meat and heating of the meat were observed all the way to the interior. Campylobacter jejuni, Salmonella O7, and Listeria monocytogenes were inoculated into chicken breasts, which were then cooked at set temperatures of 60 and 65°C for 15, 30, 60, 90, and 120 min. C. jejuni survived for up to 30 min of cooking, Salmonella O7 survived for up to 60 min of cooking at 60°C and 30 min at 65°C, and L. monocytogenes survived for up to 90 min of cooking at 60°C and 60 min at 65°C. Thus, to prevent infection and illness caused by the three tested bacteria species, LT-LT cooking for 120 min at 60°C and 90 min at 65°C is recommended.