Inactivation of Salmonella and Shiga-toxin producing Escherichia coli on soft wheat kernels using vacuum steam pasteurization

Yawei Lin; Quincy Suehr; Kirk Dolan; Senay Simsek; Teresa M Bergholz

doi:10.1016/j.ijfoodmicro.2023.110375

Inactivation of Salmonella and Shiga-toxin producing Escherichia coli on soft wheat kernels using vacuum steam pasteurization

Int J Food Microbiol. 2023 Dec 2:406:110375. doi: 10.1016/j.ijfoodmicro.2023.110375. Epub 2023 Aug 30.

Authors

Yawei Lin¹, Quincy Suehr², Kirk Dolan³, Senay Simsek⁴, Teresa M Bergholz⁵

Affiliations

¹ Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824, United States of America.
² Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824, United States of America.
³ Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824, United States of America; Department of Biosystems and Agricultural Engineering, Michigan State University, East Lansing, MI 48824, United States of America.
⁴ Whistler Center for Carbohydrate Research, Department of Food Science, Purdue University, West Lafayette, IN 47907, United States of America.
⁵ Department of Food Science and Human Nutrition, Michigan State University, East Lansing, MI 48824, United States of America. Electronic address: Tmb@msu.edu.

PMID: 37660435
DOI: 10.1016/j.ijfoodmicro.2023.110375

Abstract

Wheat, the raw material for flour milling, can be contaminated with enteric pathogens, leading to outbreaks linked to flour. In previous lab-scale studies, vacuum steam treatment was able to reduce Salmonella Enteritidis PT30 and Shiga-toxin producing E. coli (STEC) O121 levels on soft wheat kernels while maintaining flour quality and gluten functionality. This study used a newly designed lab-scale vacuum steam pasteurizer (VSP) to evaluate its efficacy to inactivate multiple strains of Salmonella and STEC on soft wheat by modeling the non-isothermal time-temperature history during treatment and reduction of the microbial populations. The results demonstrated that vacuum steam treatment could effectively disinfect wheat grains inoculated with enteric pathogens. In this study, Salmonella strains were less thermally resistant than STEC strains. The D_75°C of Salmonella strains were 2.8 and 3.2 min, and the D_75°C of STEC ranged from 3.1 to 4.6 min. E. faecium had a D_75°C of 3.3 min, which indicates that it could be used as surrogate for larger scale evaluation of vacuum steam pasteurization in the future but was not conservative compared to some of the STEC strains.

Keywords: Low moisture; STEC; Salmonella; Vacuum steam; Wheat.

MeSH terms

Food Microbiology
Pasteurization / methods
Salmonella enteritidis
Shiga-Toxigenic Escherichia coli*
Steam
Triticum
Vacuum

Substances

Steam