Modeling the effect of temperature and macronutrient composition on water activity and the influence on thermal resistance of Salmonella

The Quick Summary

Food can have tiny germs, like Salmonella, that can make us sick if we eat them. To keep us safe, we cook food to kill these germs. How wet or dry food is, called “water activity,” can change how easy or hard it is to kill germs with heat. Scientists found that measuring water activity when food is hot (like during cooking) is better for knowing if germs will die than measuring it when food is cold. Also, the different parts of food, like how much protein or fat it has, might change water activity too, but we don’t know exactly how much. This study is looking at many different food mixtures made from ingredients like soy protein and rice flour. They want to see how temperature and these different food parts affect water activity, and how that helps Salmonella survive the heat. This helps us understand better how to make sure our food is safe.

Practical Implications

This study has significant practical implications for food manufacturers and regulators in ensuring food safety. It underscores the critical need to consider water activity measurements at processing temperatures, rather than solely relying on room temperature values, for accurately predicting pathogen thermal resistance. Furthermore, by quantifying the effect of macronutrient composition on water activity and pathogen survival, the research provides valuable data for formulating safer food products. This could lead to the development of more precise thermal processing guidelines, preventing both under-processing (which can lead to foodborne illness outbreaks) and over-processing (which can degrade product quality and increase energy costs). Ultimately, these findings will enable food scientists and engineers to design more effective and scientifically sound pathogen control strategies across a wider range of food matrices.

Potential Use in Indonesia

In Indonesia, with its hot, humid tropical climate and vibrant traditional markets and street food scene, these findings are highly relevant. Understanding how water activity, temperature, and diverse local ingredients (like coconut-based products or various starches) affect Salmonella’s heat resistance can help improve food processing and storage guidelines for popular local dishes and snacks. This knowledge is crucial for enhancing food safety practices among street food vendors and small-scale producers, ultimately reducing foodborne illness risks in a context where refrigeration is not always readily available or consistently used.

Original Abstract

Water activity (a(w)) is temperature-dependent, and studies have shown that a(w) measured at elevated temperature better reflects pathogen thermal resistance at process temperature than product a(w) measured at room temperature. Macronutrient composition can also affect the a(w), yet the effect hasn’t been fully quantified. This study first investigated the temperature dependence of a(w) in thirteen food matrices formulated from soy protein powder, rice flour, and soy oil by measuring a(w) from……

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