Microbial Contamination Risks From Adjacent and Nearby Land: Evidence and Implications for Produce Safety

Consumers' demand for fresh produce is rising due to dietary preferences and public health campaigns. Fresh produce is often consumed raw or minimally processed to retain nutrient content. If contaminated, fresh produce can become a vehicle for pathogen transmission and potentially cause outbreaks. Contamination may occur within the farm border, but some evidence suggests different sources on adjacent and nearby land may be off-farm contributors. Natural ecosystems (e.g., wildlife habitats, vegetation), agricultural activities (e.g., livestock operations, manure and compost application, wastewater discharge), residential and industrial activities (e.g., septic systems, waste discharge), and recreational uses (e.g., parks, campgrounds, golf courses) all represent potential contamination sources. Environmental pathogens from adjacent land can reach produce farms through diverse pathways influenced by meteorological drivers (e.g., rainfall, wind) or by human activities, equipment, and animal intrusion. These adjacent land inputs interact with each other and farming practices, creating complex contamination mechanisms. This paper explored microbial contamination sources from adjacent and nearby land and proposed a risk ranking model with implications for produce safety. It aimed to provide an overall understanding of the interaction between environmental and adjacent land sources as a basis for future risk assessment and management research.