Factors like temperature, pH and water activity (a measure of food dryness) are essential for Salmonella growth. This is because all these factors have an impact on the growth and survival of Salmonella, and can vary across the supply chain and from one processing environment to another. Also Salmonella levels vary, depending on the production stage and environmental conditions, which makes predicting growth of the bacteria difficult.
To develop a tool capable of modelling the growth of Salmonella in pork, the researchers turned to Combase – a database on microbial growth in different environments.
Developed by IFA in collaboration with USDA Research Service and Australia’s Food Safety Centre, Combase contains over 700 records describing growth of Salmonella in a wide variety of conditions relevant to the pork supply chain.
Different models were then combined to give predictions on the concentrations of Salmonella at different production stages and under varying temperature, water activity and pH levels. Predictions can be made with inputs ranging from 0-30°C, 2.5 - 7 pH and 0.78-1 for water activity.
The estimates obtained from the software were validated by comparing them against actual Salmonella levels in several pork products.