Are fermented foods safe for human health? A systematic analysis of the literature

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Background Fermented foods (FF) are widely consumed across different dietary cultures and are increasingly recognized for their nutritional and functional properties. Although fermentation can improve food preservation and safety, there are still concerns about microbiological and chemical hazards. Given the growing consumption of FF, it is essential to conduct a systematic evaluation of their safety to support evidence-based risk-benefit assessments. Objectives This review aimed to establish the safety of FF for human consumption and to identify the main microbiological and chemical hazards associated with these foods, including their occurrence, exposure and potential risks. Design A systematic scoping review was conducted in accordance with a predefined protocol aligned with PRISMA principles. Relevant human studies were identified through searches of the PubMed, Scopus and Cochrane Library databases. The eligibility criteria were defined using a PECO framework and included all population groups and a broad range of FF across major food categories. Alcoholic beverages with an alcohol content above 1.25% were excluded. The outcomes included the occurrence of hazards, associated exposure and risk, and reported foodborne outbreaks. Results Microbiological hazards were predominantly associated with pathogens such as Salmonella , pathogenic Escherichia coli, Listeria monocytogenes, Campylobacter jejuni , and Clostridium botulinum , with dairy and fermented meat products most frequently implicated in outbreaks. However, these risks were largely linked to contaminated raw materials, inadequate processing conditions, or post-process contamination rather than fermentation itself. Chemical hazards included mycotoxins, heavy metals, polycyclic aromatic hydrocarbons, and acrylamide. Most available risk metrics indicated low concern under typical consumption scenarios, although certain products, such as specific cheeses and cereal-based foods, showed higher exposure levels. Importantly, several chemical hazards were associated with raw material contamination or thermal processing rather than the fermentation process. Conclusion Overall, the identified risks associated with FF are predominantly driven by contaminated raw materials, inadequate processing practices, and environmental factors, rather than by fermentation itself, supporting the safe integration of FF into modern diets when appropriate hygienic and technological conditions are ensured. These findings emphasize the importance of targeted risk management strategies focused on raw material quality, process control and harmonized risk assessment approaches.