Ohmic heating effects on Listeria monocytogenes inactivation, and chemical, physical, and sensory characteristic alterations for vacuum packaged sausage during post pasteurization

Abstract

Listeria monocytogenes contamination of processed sausage occurs primarily after cooking and during packaging, causing significant annual economic loss throughout the industry. Post pasteurization ohmic heating of vacuum packed sausages was proposed for effective post packaging decontamination. Ohmic heating of 75 °C for 30 s (OH) was investigated and compared to conventional heating at 75 °C for 30 s (CT (30 s)) and for 2 min (CT (2 min)) regarding L. monocytogenes inactivation, product properties, and sensorial attributes. OH, having a shorter come up time, completely inactivated L. monocytogenes with more than a 5-log reduction, whereas CT (30 s) and CT (2 min) achieved 3- and 4-log reductions, respectively. Ohmic heating did not statistically change sausage chemical composition, pH, lipid oxidation, cooking loss, or water holding capacity and only minimally altered color and texture. Regarding CT (2 min), the longer heating time increased cooking loss and decreased tenderness. Despite color and texture changes after both ohmic and conventional heating being detected by instrumental analysis, consumers were unable to detect any sensory differences between the methods. In conclusion, OH shows potential in sausage production, for both food safety and process efficiency, with minimal effect on sausage quality.