Non-thermal effects of microwave processing on inactivation of Clostridium Sporogenes inoculated in salmon fillets

摘要

Microwave processing has been a promising technology in improving quality and ensuring microbial safety of food products, while non-thermal effects of microwave is in controversy. The objective of this study was to investigate the non-thermal effects of microwave electromagnetic (EM) fields on Clostridium Sporogenes (surrogate of Clostridium botulinum) inoculated in salmon fillets using same time-temperature profiles method. The inoculated salmon fillets were processed by a single-mode pilot microwave processing system with different radiation time (2, 3 and 4 min) and holding time (0, 2 and 4 min). Corresponding water bath treatments were designed for each microwave processing to obtain matching time-temperature profiles. Results showed that the same time-temperature profiles method was successfully achieved to evaluate the microwave non-thermal effects in salmon fillets. With equal or lower thermal lethality value, microwave processing brought significantly higher (P < 0.05) reduction values than water bath treatment. This determined the non-thermal effects of microwave EM fields. And the non-thermal effects increased with longer microwave radiation time and was intensified by higher temperature. However, the following holding section will weaken the additional inactivation efficiency of microwave non-thermal effects. Results suggested that microwave processing could provide better bacteria control with lower thermal processing level.