Location: Environmental Microbial & Food Safety Laboratory
Project Number: 8042-32420-009-000-D
Project Type: In-House Appropriated
Start Date: Mar 17, 2021
End Date: Mar 16, 2026
Objective:
Objective 1: Evaluate the microbial safety of alternative fresh produce production systems and the efficacy of preventive practices.
Sub-objective 1.a: Investigate sources of pathogen contamination on fresh produce grown by aquaponics (APs).
Sub-objective 1.b: Determine the relationship of AP design and operational practices on microbiome characteristics and efficacy of water and probiotic treatments in reducing pathogen risks on produce.
Sub-objective 1.c: Develop mitigation strategies for controlling pathogens in microgreen and sprouts.
Objective 2: Develop and evaluate novel mitigation strategies to control foodborne pathogens at pre- and post-harvest levels.
Sub-objective 2.a. Develop pre-harvest interventions to control pathogens on leafy greens.
Sub-objective 2.b. Develop intervention strategies to control pathogens on fresh-cut leafy greens while maintaining quality and shelf life.
Sub-objective 2.c. Optimize fresh-cut process to reduce pathogen presence on tomatoes.
Objective 3: Characterize pathogen interactions with multi-species biofilms and efficacy of interventions on abiotic surfaces.
Sub-objective 3.a. Investigate single and multi-species biofilm formation by foodborne bacterial pathogens in fresh produce processing environments.
Sub-objective 3.b. Develop mitigation strategies to control biofilm formation in fresh produce processing environment.
Approach:
Sources of pathogen contamination of fresh produce grown using aquaponics production (AP) system will be investigated. The aquaponics system inputs (seeds, transplant media, water, fish, feed) will be analyzed for fecal coliforms, spoilage bacteria, and foodborne pathogens (Shiga-toxigenic E.coli, Salmonella spp., Listera monocytogenes). Fresh produce (basil, cilantro, brassica leafy greens, pepper, pak choi) grown by AP system will be evaluated for spoilange and pathogenic bacteria, and produce yield. The effect of probiotics in controlling surrogate pathogens (avirulent E. coli, L. innocua, Salmonella spp.) on fresh produce seeds/seedlings and APs water will be determined. Nanobubble, UV light, and plasma functionalized water will be evaluated for seed germination. plant growth promotion, and system disinfection. Changes in fish and plant microbiome due to antimicrobial treatments will be evaluated. Sprout seeds (alfalfa, broccoli, clover, mung bean, radish) treated with glucosonilate compounds will be evaluated for rate of seed germination, inhibition of foodborne pathogens, and potential transfer of inoculated pathogens to sprouts. Seeds of microgreens contaminated with pathogens will be grown in different growing media to determine the effect of growth media on pathogen survival, and yield and quality of microgreens. Biocontrols and plant-based nanoemulsions will be investigated as pre-harvest interventions to control pathogen surrogate E. coli O157:H12 at the farm level. The effect of size distribution of particulates generated during commercial fresh-cut vegetables (baby spinach, diced cabbage, shredded lettuce) operation on wash water turbidity and subsequent pathogen cross-contamination will be investigated. Te effect of wash-cut sequence on pathogen cross-contamination on tomatoes will be evaluated and fresh-cut processing of tomatoes will be optimized to minimize pathogen contamination. Multi-species biofilm formation of L. monocytogenes and E. coli O157:H7 with promotor strain Ralstonia insidiosa will be assessed on different equipment surfaces at variable flow rates. Biofilm studies will be simulated in pilot plant to identify potential hotspots of biofilm formation. Novel antimicrobials such as plant-based nanoemulsion, antagonistic bacteria; and new technologies (dry steam, nonflammable ethanol, surface coating) will be investigated for biofilm removal in laboratory and pilot plant studies, respectively.
