By Vikas Kumar Galipothu, Katelynn Stull and Manreet Singh Bhullar, Department of Horticulture and Natural Resources, Kansas State University

Fresh fruits and vegetables are central to healthy diets worldwide, yet they also are highly vulnerable to contamination. Foodborne pathogens can persist on food-contact surfaces, making them a leading cause of illness and deaths linked to fresh produce outbreaks. According to the Centers for Disease Control and Prevention (CDC), Listeria ranks among the most severe threats, with outbreaks tied to melons, leafy greens and other fresh produce commodities.

Unlike some pathogens, Listeria has an unsettling ability to survive in hard-to-clean crevices, drains and food-handling equipment. Even with routine sanitation, it can establish long-term niches, posing a threat to both consumer safety and industry reputation. Traditional sanitizers, such as chlorine, have served the industry for decades, but their effectiveness is influenced by water chemistry and environmental conditions, and they may leave residues or byproducts of concern. Ultraviolet-C (UV-C) light has emerged as a promising alternative that can be customized for unique applications tailored to commodity-specific needs and target food-contact surface areas.

Food Contact Surfaces and Cross-Contamination

One critical node in the fresh produce supply chain is the risk of contamination from food-contact surfaces. Several outbreaks have occurred because of poor cleaning and sanitization practices, leading to cross-contamination. One of the most used food-contact surfaces in the produce industry is plastic harvest bins (reusable plastic containers [RPC] or harvest buckets). Widely used for packing and transporting fruits and vegetables, these plastic containers offer sustainability benefits by reducing waste, extending product freshness and withstanding multiple harvest cycles. However, textured surfaces and frequent reuse make them potential reservoirs for pathogens.

UV-C Light as a Non-Chemical Intervention

UV-C light, with a germicidal wavelength of 254 nanometers, has been studied extensively for its antimicrobial properties. By damaging microbial DNA and preventing replication, UV-C provides a physical, residue-free, non-thermal disinfection method. Some advantages include being effective against a broad spectrum of pathogens; offering a non-thermal process that leaves no chemical residues; easy retrofitting ability to existing packing lines; and providing rapid treatment compared to many chemical alternatives.

So, why is it not widely used? The challenge lies in ensuring that UV-C light (in adequate numbers of photons) reaches the target contamination sites, including hard-to-access areas, at a sufficient dose to disrupt the cellular functions of the pathogens and result in microbial inactivation.

A Case Study on RPC Disinfection

The authors’ research team conducted a case study evaluating the effectiveness of UV-C disinfection on RPCs. The study investigated how UV-C light could reduce Listeria innocua (a surrogate for L. monocytogenes) on RPC surfaces, including those in difficult-to-reach crevices. The shape and surface characteristics of food-contact surfaces necessitate a unique approach when applying UV-C light for food-safety applications. For this case study, a unique UV design (called UV Tunnel) was developed to uniformly expose the maximum target surface area of the RPCs with adequate UV fluence to inactive artificially inoculated Listeria cells.

Surfaces from multiple orientations (entry, exit, right and left sides) were tested to capture potential variation in UV exposure. The results were clear: Increasing UV-C intensity correlated with significantly greater microbial reduction, hitting ~3 3.5 log reduction in 60 seconds. Importantly, the orientation of the RPC surfaces had little impact on treatment effectiveness, suggesting that consistent disinfection could be achieved across different sides of the container without making significant changes to the existing conveyor belt set-up at the packing lines or bin-washing lines, making it a promising tool for retrofitting.

Broader Implications for Industry

While chlorine and other sanitizers likely will remain part of the sanitation toolbox for the fresh produce industry, UV-C light offers a complementary approach that aligns with industry trends toward sustainability, consumer safety and regulatory compliance. By reducing reliance on chemicals, UV-C also may appeal to growers, packers and retailers seeking residue-free disinfection methods that support clean-label initiatives and organic produce. The potential applications go beyond food-contact surfaces such as RPCs. UV-C could be applied to a range of surfaces in packinghouses, distribution centers and retail settings, from conveyor belts and cutting boards to harvesting tools and packaging materials. The ability to disinfect surfaces quickly and effectively particularly is valuable in environments where downtime is costly.

Conclusion

Food safety is a shared responsibility, and technologies like UV-C light offer innovative, non-chemical tools to combat persistent pathogens. This case study demonstrates the practical value of UV-C disinfection on reusable plastic containers and highlights its role within an integrated food-safety strategy. As produce consumption and consumer expectations for safety and transparency grow, pairing UV-C with complementary interventions such as mild sanitizers or physical agitation holds promise for addressing challenging environments like biofilms. When validated and thoughtfully integrated (in a tailored application), UV-C represents a proactive, sustainable step forward in safeguarding fresh produce and strengthening consumer confidence. 

Vikas Kumar Galipothu is a Ph.D. student in the Department of Horticulture and Natural Resources at Kansas State University. His work explores the integration of UV-C light and sanitizers to enhance the safety of fresh produce.