Feed-borne hazards in hydroponic and conventional fodder production: a comparative risk assessment

Animal nutrition is a cornerstone of modern livestock production, as feed represents both the largest input cost and the primary determinant of animal growth, health, and productivity. Ensuring feed safety is therefore fundamental to the broader food safety chain, reflecting the principles of the One Health framework, which emphasizes the interconnection between animal, human, and environmental health. In this context, conventional fodder production systems (pasture, hay, silage) remain the backbone of ruminant nutrition but are inherently vulnerable to contamination. Soil contact, climatic variability, and suboptimal storage practices may result in microbial pathogens, parasites, mycotoxins, and physical or chemical hazards entering the feed chain. Well-documented examples include silage-associated Listeria monocytogenes, Salmonella contamination from manure and soil, and productivity losses linked to aflatoxins, fumonisins, and zearalenone. Additional risks such as pesticide residues, heavy metals, and foreign objects further highlight the multifactorial nature of fodder-related hazards, with significant repercussions for animal health, farm economics, and public health through zoonotic transmission and carry-over into food products. In recent decades, hydroponic fodder production has emerged as an innovative alternative. This technology, based on sprouting cereal grains in controlled, soil-free environments, enables rapid biomass production within 7–10 days, continuous year-round availability, and reduced land requirements. Moreover, the adoption of hydroponic systems fundamentally alter the relevance of different hazard types, with potential implications for feed safety. The present thesis applies a qualitative risk assessment framework to systematically identify and compare the risk associated to different hazards in conventional and hydroponic fodder production. Each hazard was evaluated in terms of severity and likelihood of occurrence, and comparative risk matrices were developed to visualize differences between systems. The results indicate that while hydroponic systems reduce the risk associated with most hazards, particularly parasites, soil pathogens, and heavy metals, specific vulnerabilities linked to moisture, microbial ecology, and water management are also introduced, with implications for mold growth and mycotoxin accumulation, biofilm-associated opportunistic bacteria, and chemical residues from disinfectants or seed treatments. These findings provide a scientific basis for developing tailored risk management strategies and addressing critical control points for each production system. By combining hazard identification through literature review with comparative risk rating, the study contributes to improved understanding of fodder safety, offering practical insights for safer, more sustainable, and resilient livestock production.