Minimization of Heterocyclic Amines and Thermal Inactivation of Escherichia coli in Fried Ground Beef

Abstract

Background: Heterocyclic amine carcinogens are formed during the cooking of a number of foods, especially well-done meats. Lower temperatures and shorter cooking times can minimize the formation of these carcinogens, yet a major food safety concern is that pathogens in the meat must be thermally inactivated. This study investigated cooking techniques that minimize heterocyclic amine formation while simultaneously destroying contaminating bacteria. Methods: Ground beef patties were inoculated with Escherichia coli K12 bacteria and fried to internal temperatures ranging from 35°C to 70°C in a skillet preheated to 160°C, 180°C, or 200°C. Each patty was then analyzed for four common heterocyclic amines and for surviving bacteria. Additionally, the frequency of turning of the beef patty during cooking was varied (a single turn or multiple turns), length of time required for each patty to reach 70°C was recorded, and heterocyclic amine levels were determined. An additional pan temperature of 250°C was tested for its effect on heterocyclic amine formation but not on bacterial killing. Statistical tests were two-sided. Results: Colonyforming bacteria were reduced by five orders of magnitude at internal temperatures greater than 60°C, regardless of cooking method, and were completely inactivated at 70°C. For patties turned just once, heterocyclic amine levels increased as the cooking temperatures increased. However, levels of heterocyclic amines were statistically significantly lower with turning every minute. For each pan temperature, patties reached 70°C internal temperature sooner when they were turned every minute than when they were turned

Dietary Mutagen Exposure and Risk of Pancreatic Cancer

“…Adjustment of these variables did not significantly alter the OR estimations. Laboratory studies have shown that the formation of HCA during cooking can be decreased by natural and synthetic antioxidants, by tryptophan or proline, by removing the essential creatine through marinating or brief microwave cooking before frying or broiling, and by decreasing the cooking temperature and increasing the frequency of flipping the meat during cooking (44)(45)(46). These sources of HCA variability were not measured in our study and may lead to nondifferential misclassification of HCA exposure, yielding biased estimates in either direction.…”

Potential sources of carcinogenic heterocyclic amines in the Chinese diet: results from a 24-h dietary recall study in Singapore

“…As the food is fried, it is stirred almost continuously so that the hot oil covers every part of the food, hence its name. Recent work suggests that flipping of meat patties lowers the surface temperature intermittently and may reduce the amount of HCAs formed (Salmon et al, 2000), although simulation studies could not fully explain these reductions based on a thermal (cooking time or temperature-related) effect (Tran et al, 2002). While more studies on the mechanism of this effect are needed, it remains possible that the effect of very high temperatures may in fact be mitigated by the short cooking time and constant stirring.…”

Food Borne Carcinogens: A Dead End?

“…Based on the same principle, microwaving beef patties before frying caused a reduction in mutagenicity possibly due to the loss of water and HCA precursors during the pretreatment . Flipping the food frequently reduced the formation of HCAs because the meat has spent less time in contact with the hot surface (Salmon et al, 2000;Tran et al, 2002); and shortening cooking time or lowering cooking temperature also resulted in lower heat and mass transfer. As a result of the above-mentioned studies, easyto-adopt cooking practices that reduce exposure to HCAs can be recommended.…”