Holding Fresh-Cut Produce under Refrigeration May Not Prevent Pathogen Growth: Implications for Time-Temperature Control to Reduce Risk

Q: Which pathogens and produce types were tested in the study?

The study examined Listeria monocytogenes, Shiga toxin-producing E. coli, and Salmonella enterica on cucumber, onion, pepper, mango, and tomato.

Q: At what temperatures was pathogen growth evaluated?

Pathogen growth was evaluated at 5°C, 10°C, and 22°C, including assessment on refrigeration-level conditions.

Q: What overall conclusion was drawn about refrigeration holding of fresh-cut produce?

Holding fresh-cut produce at or near refrigeration temperatures (5 or 10°C) may not control the risk of pathogen growth for all tested produce-pathogen combinations.

Oct 2, 2026

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The FDA Food Code recommends holding fresh-cut produce below 5°C to limit pathogenic microorganism growth. This study tested growth of Listeria monocytogenes, Shiga toxin-producing Escherichia coli, and Salmonella enterica on cucumber, onion, pepper, mango, and tomato at 5, 10, and 22°C using surface pasteurization, inoculation, and time-based enumeration via Δ-log CFU/g. Mango showed no growth at 5–10°C, but SALM and STEC grew at 22°C; several combinations grew significantly at 5°C or 10°C. Findings indicate refrigeration-level holding (5–10°C) may not reliably control pathogen risk.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages10

Reading Time25 min

AccessFree to download

Abstract

Introduction

Food Code and time-temperature control (TCS foods)

Materials and Methods

Produce preparation

Pathogen selection and maintenance

PEER-REVIEWED ARTICLE Food Protection Trends, Vol 41, No. 1, p. 46–55 Copyright© 2021, International Association for Food Protection 2900 100th Street, Suite 309, Des Moines, IA 50322-3855 Bingzhuo C. Zhao, Eleanor J. Hanson and Barbara H. Ingham* Dept. of Food Science, 1605 Linden Drive, University of Wisconsin–Madison, Madison, WI 53706, USA Holding Fresh-Cut Produce under Refrigeration May Not Prevent Pathogen Growth: Implications for Time-Temperature Control to Reduce Risk ABSTRACT The U.S. Food and Drug Administration Food Code suggests that holding fresh-cut produce at < 5°C will limit growth of pathogenic microorganisms. Here, we determined whether cucumber, onion, pepper, mango, and tomato supported growth of Listeria monocytogenes (LM), Shiga toxin-producing Escherichia coli (STEC), and Salmonella enterica (SALM) at 5, 10, and 22°C. Produce was surface-pasteurized, diced, inoculated with single-pathogen cocktails, and incubated. Survivors were then enumerated with change in population (Δ-log CFU per gram) determined over time. Mango did not support pathogen growth at 5 or 10°C, but SALM and STEC exhibited significant (P < 0.05) growth on mangoat 22°C (2.85 and 1.41 Δ-log CFU/g, respectively) . At 5°C, significant (P < 0.05) growth was seen on cucumber inoculated with SALM and LM; onion and pepper inoculated with LM; and tomato inoculated with STEC. At 10°C, freshcut cucumber, onion, and pepper supported significant (P < 0.05) increases in SALM, STEC, and LM, along with SALM on tomato; Δ-log ranged from 3.37 (onion, LM) to 5.40 CFU/g (pepper, SALM) . Growth of pathogens was not significantly different (P < 0.05) at 10 and 22°C for SALM or STEC inoculated onto onion, pepper, cucumber, or tomato. Results suggest that holding fresh-cut produce at or near refrigeration temperatures (5 or 10°C) may not control risk of pathogen growth. INTRODUCTION As Americans look to fresh fruits and vegetables as healthy diet choices (16, 33), produce consumption has increased. However, the lack of a lethality step in the manufacture of fresh-cut produce and a global produce distribution network have contributed to increased foodborne illness outbreaks linked to fresh produce (3). Listeria monocytogenes (LM), Salmonella enterica (SALM), and Shiga toxin-producing Escherichia coli (STEC) have been isolated from raw produce (21, 29, 37–39) and have been linked to produce-related outbreaks (1, 8, 24, 35, 46-47). In 2015, Salmonella Poona was identified in an outbreak associated with cucumber that resulted in >900 cases of illness, 204 hospitalizations, and six deaths (4, 5). In 2011, an outbreak of listeriosis traced to *Author for correspondence: Phone: +1 608.263.7383; Fax: +1 608.262.6872 ; Email: [bhingham@wisc.edu](bhingham@wisc.edu) 46 Food Protection Trends January/February whole cantaloupe caused 146 illnesses in 28 U.S. states and led to 32 deaths and one miscarriage (30). The U.S. Food and Drug Administration (FDA) Food Code aims to ensure safe food handling and preparation in retail food establishments across the United States. The Food Code identifies certain foods as time-temperature control for safety (TCS) foods; these foods require timetemperature control to limit growth or toxin formation by pathogenic microorganisms (43). TCS foods specifically cited in the definition are raw seed sprouts, cut melons, cut leafy greens, and cut tomatoes or mixtures of cut tomatoes that are not modified in a way so that they are unable to support pathogenic microorganism growth or toxin formation (43). Foods not specifically cited are designated non-TCS on the basis of pH and water activity (Table 1). Except during preparation or similar steps, or under certain holding conditions, TCS foods must be maintained at ≤5°C (43). Most fruit have a natural or normal pH < 4.2 and would be considered non-TCS. Exceptions are cut melon and cut tomato that are specifically cited in the definition ofTCS foods. Vegetables tend t

FAQs

Which pathogens and produce types were tested in the study?

The study examined Listeria monocytogenes, Shiga toxin-producing E. coli, and Salmonella enterica on cucumber, onion, pepper, mango, and tomato.

At what temperatures was pathogen growth evaluated?

Pathogen growth was evaluated at 5°C, 10°C, and 22°C, including assessment on refrigeration-level conditions.

What overall conclusion was drawn about refrigeration holding of fresh-cut produce?

Holding fresh-cut produce at or near refrigeration temperatures (5 or 10°C) may not control the risk of pathogen growth for all tested produce-pathogen combinations.

Oct 2, 2026

Uploaded by Cart