Challenge Testing to Determine Growth of Listeria monocytogenes on Fresh Enoki Mushrooms at 4 °C and 10 °C Storage Temperatures

IF 2.8 4区农林科学 Q3 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Journal of food protection Pub Date : 2025-07-03 DOI:10.1016/j.jfp.2025.100577

Jacqueline P. Upham , J. Austin Markell

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Abstract

Recent listeriosis outbreaks and recalls related to high prevalence and counts of Listeria monocytogenes in enoki mushrooms imported from South Korea and China represent a current food safety concern. Unlike domestically produced mushrooms, imported products are often packaged without free air exchange and are associated with a longer shelf life. The present study used challenge tests to investigate the potential for harvested enoki mushrooms stored under refrigeration to support the growth of L. monocytogenes, to better inform food safety regulators of the risk associated with low levels of L. monocytogenes on enoki mushrooms ready for retail. Counts of L. monocytogenes rose significantly on enoki mushroom portions from 30 to 1,000 CFU/g within 4 days at 10 °C (n = 202) and 9 days at 4 °C (n = 138). Curve fitting into the Baranyi growth model indicated a 100-fold increase in 3.7 days (10 °C) and 8.8 days (4 °C). Additional factors examined in the study included the effect of the presence of residual mushroom growth substrate and Listeria innocua as enoki background microbiota. L. innocua was associated with significantly (p < 0.001) lower maximum levels of L. monocytogenes during challenge tests at 10 °C. High prevalence of L. innocua was observed on imported enoki (15 of 18 lots) and is of concern as this species shares environmental niches with L. monocytogenes and thus a risk factor; monitoring for it should be promoted. L. monocytogenes growth on enokis was accelerated when residual enoki growth substrate was present, with a significant (p < 0.05) impact on L. monocytogenes levels by Day 2 at 10 °C and Day 3 at 4 °C, which prompts consideration for removing substrate before packaging. Finally, small-scale sampling suggests a lack of consistency in baseline contamination of L. monocytogenes among individual packages of the same lot, of interest with regards to sampling approaches for imported enoki mushrooms prior to retail.

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在4°C和10°C的储存温度下，对新鲜的益木菇上单核细胞增生李斯特菌的生长进行挑战试验。

最近从韩国和中国进口的针叶菌中李斯特菌的高流行率和数量导致了李斯特菌病的爆发和召回，这是当前的食品安全问题。与国内生产的蘑菇不同，进口产品的包装通常没有自由空气交换，因此保质期更长。本研究使用挑战试验来调查冷藏保存的收获的益木菇支持单核细胞增生乳杆菌生长的潜力，以便更好地向食品安全监管机构通报准备零售的益木菇中低水平单核细胞增生乳杆菌的相关风险。在10°C （n=202）和4°C （n=138）条件下，分别在4天（n=138）和9天内，嗜单核增生乳杆菌数量从30 CFU/g显著增加到1000 CFU/g。拟合Baranyi生长模型的曲线显示，在3.7天（10°C）和8.8天（4°C）时，产量增加了100倍。研究中检查的其他因素包括残留蘑菇生长基质的存在的影响，以及作为enoki背景微生物群的无痕李斯特菌。无头乳杆菌与(p

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来源期刊

Journal of food protection 工程技术-生物工程与应用微生物

CiteScore

4.20

自引率

5.00%

发文量

296

审稿时长

2.5 months

期刊介绍： The Journal of Food Protection® (JFP) is an international, monthly scientific journal in the English language published by the International Association for Food Protection (IAFP). JFP publishes research and review articles on all aspects of food protection and safety. Major emphases of JFP are placed on studies dealing with: Tracking, detecting (including traditional, molecular, and real-time), inactivating, and controlling food-related hazards, including microorganisms (including antibiotic resistance), microbial (mycotoxins, seafood toxins) and non-microbial toxins (heavy metals, pesticides, veterinary drug residues, migrants from food packaging, and processing contaminants), allergens and pests (insects, rodents) in human food, pet food and animal feed throughout the food chain; Microbiological food quality and traditional/novel methods to assay microbiological food quality; Prevention of food-related hazards and food spoilage through food preservatives and thermal/non-thermal processes, including process validation; Food fermentations and food-related probiotics; Safe food handling practices during pre-harvest, harvest, post-harvest, distribution and consumption, including food safety education for retailers, foodservice, and consumers; Risk assessments for food-related hazards; Economic impact of food-related hazards, foodborne illness, food loss, food spoilage, and adulterated foods; Food fraud, food authentication, food defense, and foodborne disease outbreak investigations.