Use of High Hydrostatic Pressure and Irradiation To Eliminate Clostridium sporogenes Spores in Chicken Breast.

High pressure has been studied for its usefulness in reducing microbial contaminants in foods. We sought to determine whether this technology could be used in combination with irradiation to develop shelf-stable products. We first determined the optimal pressure, temperature, and time conditions that would result in maximum reduction of Clostridium sporogenes spores in fresh chicken. At ambient temperature, a pressure of 6,800 atm for up to 60 min resulted in a 5-log-unit reduction. Heating the samples during pressurization at 80°C for 20 min resulted in the lowest number of survivors compared to samples that were heated and pressurized for only 1 and 10 min. Further, irradiation at a medium dose (3.0 kGy) before and after pressurization at 6,800 atm and 80°C for 1, 10, and 20 min revealed no significant differences in spore counts between samples that were pressurized and then irradiated or vice-versa. We then examined the effect of high pressure in lowering the irradiation dose necessary to eliminate all spores. The irradiation D value of C. sporogenes spores was calculated to be 4.1 kGy. Samples were then irradiated at various doses followed by pressurization at 6,800 atm at 80°C for 20 min. The irradiation D value was lowered to approximately 2 kGy, indicating that a combination of high hydrostatic pressure and irradiation can be used to produce chicken with an extended shelf life without the use of high irradiation doses.