Effectiveness of domestic food hygiene interventions on the microbiological quality of child food and childhood diarrhoea: a systematic review and meta-analysis

Background Foodborne diseases are an important cause of global morbidity and mortality, particularly among children who often experience diarrhoeal illnesses linked to foodborne enteric infections. Evidence on the effectiveness of interventions to reduce diarrhoea remains limited. This review synthesised evidence on the effectiveness of domestic food hygiene interventions on microbiological quality of child food and diarrhoea in children under five. Methods and findings Nine databases were searched, with screening and reviewing conducted independently by two reviewers. Eligible study designs included randomised and non-randomised controlled trials that clearly described a food hygiene intervention and included a concurrent control. Primary outcomes were the microbiological quality of child food and childhood diarrhoea. Risk of bias was assessed using an adapted Newcastle-Ottawa scale, and certainty of evidence using the Grading of Recommendations Assessment, Development and Evaluation approach. Of the 15 586 records identified, 11 were included. Three of four studies that assessed food contamination outcomes reported evidence of reduction in Escherichia coli , faecal coliforms or other bacteria. Eight studies (10 comparisons) reported diarrhoea outcomes, with a pooled 24% reduction in diarrhoea prevalence or incidence (risk ratio, RR 0.76, 95% CI 0.57 to 1.01). Standalone food hygiene interventions (n=2) reduced childhood diarrhoea by 51% (RR 0.49, 95% CI 0.36 to 0.65), whereas combined food hygiene interventions with water, sanitation and hygiene (WASH), nutrition and childhood development (n=8) showed no evidence of an effect (RR 0.88, 95% CI 0.68 to 1.15). Three studies had high risk of bias. Certainty of evidence was moderate for food contamination outcomes and low for diarrhoea outcomes. Conclusions Results suggest that standalone domestic food hygiene interventions can improve microbial food quality and reduce childhood diarrhoea. However, these interventions were not effective when integrated into broader packages with WASH, nutrition or childhood development. These findings underscore the importance of dedicated food hygiene interventions for improving child health outcomes. PROSPERO registration number CRD42022336954.