Bacterial contamination prevalent in ready-to-eat salads across Africa: meta-analysisFour out of ten salads in Africa carry dangerous bacteria like E. coli

Frontiers in Medicine Published June 3, 2026 DOI ↗ Editorial oversight: Dr. Amelia Tan, PhD · Internal Medicine & Chronic Disease

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Key Takeaway

Consider that ready-to-eat salads in Africa frequently contain bacterial pathogens, warranting food safety vigilance.

This systematic review and meta-analysis pooled data from 31 studies across Africa to estimate the prevalence of bacterial contamination in ready-to-eat vegetable salads. The analysis included studies reporting bacterial isolation from salad samples, with meta-analysis restricted to species reported in at least five studies to ensure stable pooled estimates.

Pooled prevalence rates were highest for Escherichia coli at 40% (95% CI: 20–64%), followed by Salmonella spp. at 32% (95% CI: 16–54%), Bacillus cereus at 28% (95% CI: 14–48%), and Staphylococcus spp. at 26% (95% CI: 13–47%). These findings indicate substantial bacterial contamination across the continent.

Limitations include the lack of prospective registration in PROSPERO and the restriction of meta-analysis to frequently reported pathogens, which may not capture the full spectrum of contamination. The authors highlight the need for strengthened food safety practices and routine microbiological surveillance to reduce the risk of foodborne illness.

Clinicians should be aware that ready-to-eat salads in Africa commonly harbor pathogenic bacteria, posing a potential health risk, especially for immunocompromised individuals. However, the review does not assess clinical outcomes or specific sources of contamination.

Eating a fresh salad should feel safe, but new data suggests a hidden risk for many people in Africa. Researchers looked at 31 different studies to understand how often dangerous bacteria appear in ready-to-eat vegetable salads. The results are clear and concerning. About 40% of these salads contained E. coli. Another 32% had Salmonella. Bacillus cereus was found in 28% of samples, and Staphylococcus in 26%. These numbers mean that a large portion of these foods carry germs that can make people very sick.

The analysis combined information from many locations to get a clearer picture. However, the review was not registered in advance, which is a standard step to ensure transparency. The researchers also only included bacteria that showed up in at least five studies to keep their numbers stable. This means some less common germs might not be fully represented.

The main message is simple: food safety practices need to get stronger. Routine testing for germs is essential to protect public health. Without this surveillance, people continue to eat food that carries a high risk of infection. The data does not suggest a cure or a new drug, but it does highlight a gap in current safety measures.

What this means for you:

Nearly half of ready-to-eat vegetable salads in Africa contain harmful bacteria like E. coli and Salmonella.

Study Details

Study typeMeta analysis

EvidenceLevel 1

PublishedJun 2026

View Original Abstract ↓

BackgroundReady-to-eat vegetable salads are increasingly consumed across Africa due to their convenience and perceived health benefits. However, these foods are often prepared without terminal heat treatment, making them potential vehicles for foodborne pathogens. Evidence of the burden and distribution of bacterial contamination in ready-to-eat vegetable salads across Africa remains fragmented. Therefore, this study aimed to perform a systematic review and meta-analysis of the prevalence of bacterial pathogens isolated from ready-to-eat vegetable salads across Africa.MethodsWe searched PubMed, Scopus, and Google Scholar on 25 September 2025. Guided by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA 2020) guidelines, eligible African studies reporting bacterial isolation from ready-to-eat vegetable salads were analyzed using random-effects models. Heterogeneity, publication bias, and single study influence on pooled prevalence were assessed. While this review was not prospectively registered in PROSPERO, we searched the registry to confirm no similar reviews existed and adhered strictly to PRISMA reporting standards.ResultsThirty-one (n = 31) studies were included. Gram-negative bacteria predominated among reported isolates. Meta-analysis was restricted to bacterial species reported in at least five studies to ensure stability of pooled estimates. Escherichia coli (40%; 95% CI: 20–64%) and Salmonella spp. (32%; 95% CI: 16–54%) were the most frequently reported organisms. Among Gram-positive bacteria, Bacillus cereus (28%; 95% CI: 14–48%) and Staphylococcus spp. (26%; 95% CI: 13–47%) were commonly identified.ConclusionReady-to-eat vegetable salads across Africa are frequently contaminated with bacterial communities, including both pathogenic and non-pathogenic organisms. This finding highlights the need for strengthened food safety practices and routine microbiological surveillance.

Bacterial contamination prevalent in ready-to-eat salads across Africa: meta-analysisFour out of ten salads in Africa carry dangerous bacteria like E. coli

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Bacterial contamination prevalent in ready-to-eat salads across Africa: meta-analysisFour out of ten salads in Africa carry dangerous bacteria like E. coli

Study Details

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Clinical research that matters. Delivered to your inbox.

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