Water Activity Influence on the Thermal Resistance of Salmonella in Soy Protein Powder at Elevated Temperatures

Publication date: Available online 11 February 2020Source: Food ControlAuthor(s): Yuqiao Jin, Juming Tang, Mei-Jun ZhuAbstractSalmonella is a leading cause of foodborne illness associated with low-moisture foods. In addition to being able to survive in low-moisture environments during long storage, Salmonella has shown sharply increased thermal tolerance making it difficult to control in low-moisture foods. This research utilized soy protein powder as a food career to study the thermal resistance of Salmonella under a wide range of temperatures and aw. Salmonella inoculated soy protein powder samples were pre-equilibrated to aw from 0.13 to 0.82 at room temperature, then subjected to heat treatment (60 to 99 ºC) under isothermal conditions. The aw of soy protein powders at 25 to 99 ºC were measured using high-temperature aw cells with humidity sensors. The D-values as a function of high-temperature aw from 0.25 to 0.70 showed a semi-log relationship under each treatment temperature level from 70 to 99 ºC. Slightly downward trends were observed when the high-temperature aw was above 0.70, showing increased effectiveness of thermal inactivation. Results from this study provide insights to assist the design of thermal treatments for control of Salmonella in intermediate- and low-moisture foods.
Source: Food Control - Category: Food Science Source Type: research