Publication
Authors
Hyeon Woo Park, Graduate Student, Food Science and Technology (FST)
Jie Xu, Postdoc, FST
V.M. Balasubramaniam, Professor, FST and Food, Agricultural, and Biological Engineering
Abigail B. Snyder, Assistant Professor, Department of Food Science, Cornell
Quick Take
Sanitation of food processing equipment and various food plant surfaces reduces hidden microbes (think harmful bacteria, virus, fungi and spoilage bacteria) in hard to clean areas and removes food allergens. However, sanitation in dry food processing environments is a major challenge for the industry. Innovative sanitation technologies are needed. Hyeon Woo Park, Dr. Jie Xu, and Dr. V.M. Balasubramaniam, all from the Department of Food Science and Technology, tested superheated steam technology, or steam heated to 200—300 C, as a sanitation medium for reducing bacteria in dry food processing plants.
Peanut butter can harbor salmonella, so the researchers felt this was a good model to mimic food residue that may be found on food processing equipment. Traditional water-based sanitization methods cannot be used in dry food processing plant surfaces as introducing water can actually cause the salmonella to grow after sanitation.
They examined the impact of water and temperature on a particular bacterium (Enterococcus faecium) using superheated steam during the sanitation experiments (Note: It’s a common practice to use the non-pathogenic E. faecium as a surrogate for salmonella. The takeaways from the study can still be applied to reduce a broader array of bacteria).
Results
Superheated steam temperature greatly affected the bacteria, with higher temperatures (up to 250 C) leading to higher deactivation of the bacteria introduced to the peanut butter residue.
Researchers also looked at how the amount of water in the peanut butter impacted this process. They found that the more water in the peanut butter, it took a shorter time to inactivate the bacteria in the peanut butter residue across all superheated steam temperatures.
In short, the most effective situation? When peanut butter residue had the highest water concentration (which caused what is known as water activity in food processing) and was sanitized using the highest temperature (250 C). The least effective technique was the lowest water concentration, which led to the lowest water activity, with the lowest steam temperature (125 C).
Knowing this interaction between water activity and temperature will improve safety during sanitation of food plant surfaces and equipment for foods with less moisture content. Introduction of superheated steam as a sanitation method may further reduce synthetic chemicals used to sanitize and disinfect surfaces in food processing.
Citation
Park, Hyeon Woo, Xu, Jie, Balasubramaniam, V.M., Snyder, Abigail B. “The Effect of Water Activity and Temperature on the Inactivation of Enterococcus Faecium in Peanut Butter during Superheated Steam Sanitation Treatment.” Food Control, vol. 125, July 2021, p. 107942., https://doi.org/10.1016/j.foodcont.2021.107942.