Location: Residue Chemistry and Predictive Microbiology Research
Project Number: 8072-41000-101-000-D
Project Type: In-House Appropriated
Start Date: Feb 10, 2016
End Date: Feb 9, 2021
This project will focus on the integration of effective intervention technologies and treatments to enhance microbial safety of fresh fruits and vegetables with a holistic approach addressing major elements (safety, quality, and shelf-life), necessary for the implementation of technologies. The ultimate goal is to reduce the risk of foodborne illnesses associated with consumption of fresh produce, while maintaining acceptable food quality and shelf-life. Specific objectives of the research program are: Objective 1 - Develop and optimize single intervention technologies to reduce pathogen populations, maintain quality, and extend shelf-life of foods. Sub-objective 1.1. Develop and optimize aerosolizing technology and pulsed light to reduce pathogen populations, maintain sensorial and nutritional quality, and extend shelf-life of fresh produce. Sub-objective 1.2. Develop new antimicrobial packaging/coating-based technologies by incorporating natural, modified and novel materials to inactivate foodborne pathogens on fresh produce. Objective 2 - Determine the synergistic/additive effectiveness of combining non-thermal processing, antimicrobial packaging and effective chemical interventions utilizing information generated from the first objective.
An integrated approach to enhance microbial safety while maintaining product quality and extending shelf life of fresh produce will be adopted by combining aerosolizing antimicrobials, pulsed light antimicrobial packaging and other interventions. The types of fresh and fresh-cut produce evaluated in the project will be those frequently involved in outbreaks of foodborne illnesses, those that are hard to sanitize due to surface characteristics, and those that cannot be washed. During the first part of the proposed project plan, we will develop and optimize new aerosolization systems, pulsed light technology, novel antimicrobial coating with incorporation of nature and bio-based substances, and antimicrobial packaging materials with controlled-release mechanisms triggered with either acids or pulsed light. The optimized/developed interventions and antimicrobial packaging will then be combined with each other, and with other effective antimicrobial treatments to study the synergistic or additive effects on pathogen inactivation while maintaining quality and shelf-life of fresh produce. When selecting combinations, technologies with different pathogen-inactivation mechanisms or synergistic interactions will be desirable. We will utilize the advanced oxidation, photochemical, and photothermal, and triggered-release mechanisms and other hurdle technologies to increase the efficacy of combined antimicrobial treatments. By combining effective intervention technologies and treatments, synergistic effects with a targeted 5-log reduction of common pathogens may be achieved. Pathogens to be included in the proposed project plan are Salmonella spp., E. coli O157:H7, L. monocytogenes and other emerging pathogens (such as non-O157 STECs). We will use a representative cocktail of 3-5 strains from each genera of bacteria that are associated with outbreaks of relevant fresh produce. Scientifically well-established inoculation, recovery, and enumeration procedures will be used. Appropriate controls will be included in each experiment, and experiments will be replicated independently at least three times. Inoculation of fresh produce will be achieved either by surface ‘spot inoculation’ where specific locations on the produce surface will be inoculated or by a ‘dip inoculation’ technique where the whole produce item will be submerged in the experimental inocula. The inoculated fresh produce will be drained and air dried in a laminar flow hood before being subjected to various treatments. After treatment with various chemicals and physical interventions, the total number of viable and injured bacteria will be determined using amended media. The effects of the individual and combined treatments on the physiochemical and sensorial quality and shelf-life will be evaluated during storage. Shelf-life will be determined based on the deterioration in product quality and increasing populations of microorganisms that render the product unacceptable to consumers.