Purpose: This study estimated the effects of rooibos and potassium lactate and sodium diacetate mixture (PL plus SDA) on growth kinetics of C. perfringens in ready-to-eat (RTE) Jokbal, consisting of pigs' feet cooked with soy sauce and spices, which is a very popular, widely sold Korean dish at the retail.
Methods: Pork forelegs were cooked in boiling water for 1.5 h with and without 10% rooibos extract and 4% PL plus SDA mixture was uniformly spread over the surface of cooked pork named Jokbal, which was sliced. One hundred µl of C. perfringens vegetative cells or spores were inoculated onto 10 g of sliced Jokbal, which was then vacuum packed or packed aerobically. Growth and survival kinetics of C. perfringens were measured as a function of time and temperature (10, 24, and 36°C).
Results: Growth of C. perfringens vegetative cells in aerobic packaged Jokbal were significantly delayed than that in anaerobic packaged. At 10°C, significantly shorter delta parameter of Weibull survival model of C. perfringens vegetative cell in Jokbal treated with a combination of 10% rooibos and 4% PL plus SDA mixture was measured than that of the control. At 24 and 36°C, addition of 10% rooibos and 4% PL plus SDA mixture significantly reduced vegetative cell growth and spore germination and growth of C. perfringens in Jokbal throughout the storage periods, regardless of packaging method.
Significance: The potential of rooibos to inhibit the growth of C. perfringens and spore germination in Jokbal may extend a rooibos as a "natural" preservative, which can be a very useful tool in the food industry responding to the current consumers’ needs.