Microbial Food Safety Aspects Along the Supply Chain of African Indigenous Vegetables. A Case Study of Leaf Amaranth (Amaranthus spp.) in Kenya

IF 2.1 4区农林科学 Q3 BIOTECHNOLOGY & APPLIED MICROBIOLOGY

Journal of food protection Pub Date : 2025-03-17 DOI:10.1016/j.jfp.2025.100485

Samuel Elolu , Benard Odhiambo Oloo , Arnold Mathew Opiyo , Susanne Huyskens-Keil

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引用次数: 0

Abstract

Microbial food safety aspects along the supply chain of fresh leaf amaranth (Amaranthus spp.) were evaluated from farms to urban supermarkets in Kenya. A total of 150 leaf samples were collected from amaranth farms, transport, wholesale, peri-urban retail markets, and supermarkets. Microbiological indicators of sanitary conditions were analyzed in terms of the prevalence and load of aerobic mesophilic bacteria, Enterobacteriaceae, total coliforms, yeasts & molds, Escherichia coli, Salmonella, and Staphylococcus aureus. Foodborne pathogens, E. coli, Salmonella, and S. aureus, were characterized through molecular screening for selected virulence genes. The prevalence of microbial contamination was highest in peri-urban retail markets, followed by wholesale markets, supermarkets, and transportation, and least on farms. Throughout the supply chain, coliforms were the most prevalent, detected in 98.7% of the samples, followed by Enterobacteriaceae (97.3%), aerobic mesophiles (96.7%), and yeasts and molds (92%). However, S. aureus was the most prevalent pathogen (87.3%), followed by Salmonella (79.3%) and E. coli the least (67.3%). Microbial load increased from the farm to peri-urban retail markets and was significantly higher in the peri-urban retail markets, i.e., 5.08–6.22 Log CFU/g (aerobic mesophiles), 5.28–6.32 Log CFU/g (Enterobacteriaceae), 5.56–6.47 Log CFU/g (coliforms), 2.02–3.59 Log CFU/g (E. coli), 3.87–4.64 Log CFU/g (S. aureus), and 3.36–4.23 Log CFU/g (Salmonella), respectively. Shiga toxin-producing E. coli virulence genes (stx1 and stx2), enterotoxin (stn), and plasmid (pCT) Salmonella virulence genes, and S. aureus virulence genes (sea) were detected in isolates from vegetables at different nodes of the supply chain. Microbial contamination levels were above the international and national thresholds, and foodborne microorganisms had pathogenic attributes. Initiatives to improve sanitation measures at each stage of the supply chain are recommended to guarantee food safety.

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微生物食品安全方面沿供应链的非洲本土蔬菜。肯尼亚叶苋菜（苋属）的个案研究。

从肯尼亚的农场到城市超市，对新鲜叶苋菜（Amaranthus spp.）供应链上的微生物食品安全问题进行了评估。从苋菜农场、运输、批发、城郊零售市场和超市共收集了150个叶子样本。对卫生条件微生物指标进行了好氧中温细菌、肠杆菌科、总大肠菌群、酵母和霉菌、大肠杆菌、沙门氏菌和金黄色葡萄球菌的流行率和负荷分析。食源性病原体，大肠杆菌，沙门氏菌和金黄色葡萄球菌，通过分子筛选选定的毒力基因进行表征。微生物污染的流行率在城郊零售市场最高，其次是批发市场、超市和交通运输，农场最低。在整个供应链中，大肠菌群最为普遍，在98.7%的样品中检测到，其次是肠杆菌科（97.3%）、好氧中温菌（96.7%）、酵母和霉菌（92%）。病原菌以金黄色葡萄球菌最多（87.3%），其次为沙门氏菌（79.3%），大肠杆菌最少（67.3%）。从农场到城市周边零售市场，微生物负荷呈上升趋势，城市周边零售市场的微生物负荷显著升高，分别为5.08 ~ 6.22 Log CFU/g（好氧嗜氧菌）、5.28 ~ 6.32 Log CFU/g（肠杆菌科）、5.56 ~ 6.47 Log CFU/g（大肠菌群）、2.02 ~ 3.59 Log CFU/g（大肠杆菌）、3.87 ~ 4.64 Log CFU/g（金黄色葡萄球菌）和3.36 ~ 4.23 Log CFU/g（沙门氏菌）。产志贺毒素大肠杆菌毒力基因（stx1和stx2）、肠毒素沙门氏菌毒力基因（stn）和质粒沙门氏菌毒力基因（pCT）、金黄色葡萄球菌毒力基因（sea）分别在供应链不同节点的蔬菜分离株中检测到。微生物污染水平高于国际和国家阈值，食源性微生物具有致病性。建议采取措施改善供应链各阶段的卫生措施，以保证食品安全。

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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.