GLOBAL – The Joint FAO/WHO Expert Meetings on Microbial Risk Assessment (JEMRA) has concluded that Good Agricultural Practices (GAP) coupled with Good Hygiene Practices (GHP) during cultivation and harvest, are the most effective means of mitigating the risk of microbial contamination.
JEMRA had a session on the prevention and control of microbiological hazards in fresh fruits and vegetables throughout the supply chain, the final session in a series of JEMRA discussions on the topic.
The first JEMRA meeting on the prevention and control of microbiological hazards in fresh fruits and vegetables was held in September 2021 and focused on fresh, ready-to-eat (RTE), and minimally processed fruits and vegetables, such as leafy greens.
The second session was held in November 2021, in which a subcommittee focused on sprouts and seeds for sprouting. The third and final meeting discussed commodity-specific interventions for all other fresh fruits and vegetables of concern.
In total, the meetings addressed four commodity groups that were clustered based on similar physical characteristics, intervention measures, and available scientific literature.
These comprised leafy vegetables and herbs, berries and tropical fruits, melons and tree fruits, and seeded and root vegetables.
Commodity-specific interventions were identified for various target bacteria, parasites, and viruses, as well as indicator organisms.
Control points were considered for each stage along the supply chain, from farm to retail. Potential chemical, biological, and physical intervention strategies were also evaluated.
To make its assessments, JEMRA reviewed available scientific literature and data to discern the efficacy of interventions for specific commodities and determined the practical merit of intervention strategies.
They considered the potential costs, availability of resources, environmental impacts, implementation difficulties, training needs, regulatory hurdles, consumer acceptance, and geographical variances.
Interventions for all commodity groups
During post-harvest processing, JERMA stressed the importance of GHP, Good Manufacturing Practices (GMP), and preventive systems based on the Hazard Analysis and Critical Control Points (HACCP) framework.
Additionally noted as significant risk factors for microbial contamination across all commodity groups were poor irrigation water quality and processing water.
When necessary, JEMRA advised treating water with ultraviolet (UV) or filtration for irrigation water, chemical sanitizers, or specific experimental, physical approaches.
The experts highlighted the need for future research to specifically explore the viability of new control technologies and their effectiveness in various applications, as there is a noteworthy lack of industry acceptance for many potential solutions.
They also called attention to the fact that the amount of foodborne illness outbreaks brought on by parasitic or viral pathogens is out of proportion to the research on mitigation strategies currently in existence, which mostly concentrates on bacterial pathogens.
Interventions for leafy vegetables and herbs
Regarding leafy vegetables and herbs, irradiation was shown to be the most effective post-harvest treatment for fresh-cut leafy greens.
Additionally, experimental data suggest that the reduction of bacterial pathogens may be achieved by combining electrolyzed water with other physical therapies, such as ultrasound or UV exposure.
JEMRA noted that the use of bacteriophage or phage lysins and the use of sanitizers are two emerging control techniques for which there is little research and potential application hurdles.
Interventions for berries and tropical fruits
There is a dearth of information on intervention strategies for berries and, to a greater extent, tropical fruits, says JEMRA.
The majority of currently published publications discuss raspberry, blueberry, and strawberry virus mitigation.
The experts noted that the efficacy of water-assisted light therapies, such as UV and pulsed light, depends on how the berries are inoculated, but they do show some promise in reducing the number of microbial contaminants.
Additionally effective was ultrasound therapy used in conjunction with chemical sanitizers, but there were also observed negative impacts on product quality.
Depending on the dose and pathogen considered, gaseous therapies such as chlorine dioxide and sulfur dioxide have varying results.
Interventions for melons and tree fruits
The most important intervention for melons and tree fruits during sorting and packing was found to be proper sanitary handling and environmental monitoring.
It’s crucial to manage process water quality, and JEMRA recommended using chemical disinfectants or UV treatment to lower the number of harmful microbes in the water.
Interventions for seeded and root vegetables
For seeded and root vegetables, a number of interventions—including irradiation, gaseous chlorine dioxide treatment, and UV decontamination—were found to be beneficial.
Another promising antibacterial combination included nisin, ethylenediaminetetraacetic acid (EDTA), and hydrogen peroxide.
JEMRA added that physical methods can enhance the delivery of chemical interventions. One such method is the integration of vacuum impregnation into a washing procedure.