Occurrence of Selected Foodborne Pathogens on Frozen Berries Collected at Retail Level in Switzerland

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

Journal of food protection Pub Date : 2025-08-22 DOI:10.1016/j.jfp.2025.100604

Silvan Tresch, Michael Biggel, Nicole Cernela, Roger Stephan

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引用次数: 0

Abstract

Berries are globally appreciated for their health benefits, particularly due to antioxidants, and have grown in popularity over recent decades. However, several foodborne outbreaks—mainly viral, caused by norovirus and hepatitis A—have been linked to both fresh and frozen berries. In contrast, the role of frozen berries in transmitting bacterial pathogens such as Salmonella spp., Escherichia coli, and antimicrobial-resistant bacteria (AMRB) remains underexplored.

To address this, we investigated both the qualitative and quantitative presence of selected pathogens. Over a three-month period (Nov 2024–Jan 2025), 100 frozen berry samples from Swiss retailers were analyzed. One-third (n = 32) were labeled organic; 96% contained imported berries. Samples included raspberries (n = 33), blueberries (n = 18), strawberries (n = 18), blackberries (n = 3), redcurrants (n = 1), and berry mixes (n = 17), with some containing blackcurrants or sour cherries (n = 10).

All samples were tested qualitatively for Salmonella spp., Shiga toxin-producing E. coli (STEC), and Listeria monocytogenes, and quantitatively for E. coli and members of the Bacillus cereus group. Extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) were also screened. Salmonella, STEC, and L. monocytogenes were not detected. E. coli counts remained below detection limits. B. cereus group members were found in 12% of samples (2.0–3.41 log CFU/g), with several strains genetically matching B. cereus s.s. Thuringiensis biopesticide strains. ESBL-E were found in 2% of samples (both Egyptian strawberries), identified by WGS as Enterobacter hormaechei carrying bla_CTX-M-15 and E. coli with bla_SHV-12.These findings support defining microbiological criteria for frozen berries in HACCP and routine food safety testing.

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在瑞士零售水平收集的冷冻浆果中发生的选定食源性病原体。

浆果因其对健康的益处而受到全球赞赏，尤其是由于其抗氧化剂，近几十年来越来越受欢迎。然而，一些食源性疾病的爆发——主要是由诺如病毒和甲型肝炎引起的病毒性疾病——与新鲜和冷冻浆果有关。相比之下，冷冻浆果在传播沙门氏菌、大肠杆菌和抗微生物细菌（AMRB）等细菌病原体中的作用仍未得到充分研究。为了解决这个问题，我们调查了所选病原体的定性和定量存在。在三个月的时间里（2024年11月至2025年1月），研究人员分析了来自瑞士零售商的100份冷冻浆果样本。三分之一（n=32）被标记为有机；96%含有进口浆果。样本包括覆盆子（n=33）、蓝莓（n=18）、草莓（n=18）、黑莓（n=3）、红醋栗（n=1）和浆果混合物（n=17），其中一些含有黑醋栗或酸樱桃（n=10）。对所有样品进行沙门氏菌、产志贺毒素大肠杆菌（STEC）和单核增生李斯特菌的定性检测，并对大肠杆菌和蜡样芽孢杆菌群的成员进行定量检测。广谱产β-内酰胺酶肠杆菌（ESBL-E）也进行了筛选。未检出沙门氏菌、产志贺毒素大肠杆菌和单核增生乳杆菌。大肠杆菌数量仍低于检出限。12%的样品（2.0 ~ 3.41 log CFU/g）检测到蜡样芽孢杆菌群成员，有多株菌株基因与苏云金芽孢杆菌生物农药菌株相匹配。在2%的样品（两种埃及草莓）中发现ESBL-E，经WGS鉴定为携带blaCTX-M-15的贺氏肠杆菌和携带blaSHV-12的大肠杆菌。这些发现支持在HACCP和常规食品安全检测中定义冷冻浆果的微生物标准。

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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.