Effects of temperature and sanitizer wash treatments on foodborne pathogen survival during storage of work-in-process fresh-cut Brassica vegetables

Authors: AMARASEKARA, NIROSHA - Oak Ridge Institute For Science And Education (ORISE); SUBEDI, DEEPAK - Oak Ridge Institute For Science And Education (ORISE); Gurtler, Joshua; VINYARD, BRYAN - Retired ARS Employee; Fan, Xuetong

Submitted to: Food Microbiology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/26/2026
Publication Date: 5/27/2026
Citation: Amarasekara, N., Subedi, D., Gurtler, J., Vinyard, B., Fan, X. 2026. Effects of temperature and sanitizer wash treatments on foodborne pathogen survival during storage of work-in-process fresh-cut Brassica vegetables. Food Microbiology. https://doi.org/10.1016/j.fm.2026.105179.
DOI: https://doi.org/10.1016/j.fm.2026.105179

Interpretive Summary: Fresh-cut produce is highly susceptible to bacterial contamination because processing breaks protective skins, releasing fluids that act as growth mediums. While washing with sanitizers is a common industry practice, there is limited information on the survival of foodborne pathogens on fresh-cut cruciferous vegetables during post-sanitization short-term storage. This study demonstrates that strict temperature control (at or below 4 C) is significantly more critical for microbial safety and shelf life of fresh-cut broccoli stalk, Brussels sprout and kale than the specific sanitizer used, as sanitizers only reduce initial populations rather than preventing growth during storage, especially if temperature abuse occurs. By maintaining cold storage, food processors can better curb pathogen growth (such as Listeria), reduce spoilage, and increase shelf life, providing actionable guidance that protects public health and minimizes product waste.

Technical Abstract: The effects of sanitizer washing and storage temperature on the survival and growth of Escherichia coli O157:H7, Listeria monocytogenes, and Salmonella enterica were evaluated on work-in-process (WIP) broccoli stalk, Brussels sprouts, and kale. WIP produce was inoculated with pathogen cocktails (ca. 8 log CFU/ml), either left untreated or washed with water, free chlorine (ca. 100 ppm), or peracetic acid (PAA; ca. 80 ppm), and stored at 4, 8, or 12 C for 7 days, during which time pathogen populations and native microbiota were enumerated and growth potentials were calculated. Results showed that storage temperature was the dominant determinant of pathogen behavior across all commodities, with populations declining or remaining stable at 4 C during the 7-day storage period but increasing by up to ~3 log CFU/g at 12 C, particularly for E. coli O157:H7 and S. enterica. Sanitizer washing reduced initial pathogen populations, with PAA generally producing greater immediate reductions than chlorine. Despite this, washing did not prevent subsequent growth during storage. Occasionally, it resulted in higher growth potentials, particularly for L. monocytogenes at elevated temperatures. Spoilage microorganisms often grew faster on washed samples than on unwashed controls. These results indicate that sanitizer washing provides only short-term reductions of pathogen growth and does not control microbial growth during WIP storage, highlighting temperature control at 4 C as the most critical intervention for ensuring the microbial safety of WIP brassica vegetables.