Ongoing Investigation of Food Safety in Aquaponics

Non-Technical Summary:<br/>
Recently, an increasing number of commercial produce buyers are requiring their supplying farms to undergo annual, third party audits to reduce the chance of food-borne outbreaks from the food they sell. Many dozens of audit questions cover worker hygiene, pesticide use, post-harvest handling, and the use of various soil amendments, such as manures. The audit questions are known beforehand and there are a number of automatic failures to protect against high-risk growing and handling conditions. Growing produce in direct contact with uncomposted animal feces is one of the automatic failures. Since the audits do not differentiate the types of feces, for example warm-blooded animal feces from cows or pigs versus cold-blooded animal feces from fish, aquaponic systems trigger an automatic failure; regardless of all other conditions on the farm. The audits assume that all feces are potentially harmful, regardless of their source. This long-term study will address the subject of indicator microbes in aquaponic water as this emerging production system faces unique challenges with regard to food safety. Though concern about food safety related to aquaponic vegetable production is understandable, aquaponic produce and fish have been shown to be consistently safe (Rakocy, 2003; Chalmers, 2004). Increasing stakeholder awareness of the state of the scientific issues regarding indicator organisms in an aquaponic setting allows all participants to make informed decisions, and learning and employing Good Agricultural Practices (GAPs) is the desired outcome of this proposed project.
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Approach:<br/>
Objective 1: Develop testing methods and regimens for aquaponic production systems focusing on microbial endpoints in vegetable tissue and system water with the eventual goal of an on-farm SOP which can be used by third party auditors to achieve ranch audit food safety certification. All samples (water and plant produce) are to be obtained in a fashion that would allow establishment of protocol(s) for future water and tissue sampling on aquaponic operations. The collected samples will be submitted to an on-island accredited testing laboratory for analyses to mimic what would be done by a farm seeking food safety certification. The second method, which is currently under investigation and will be utilized in the proposed study involves taking composite samples of various aquaponic systems, thus allowing for sampling of the entire farm at a substantially reduced cost.
<P>Objective 2: Characterize the long-term spatial and temporal variations in food safety-related microbial populations in harvestable vegetable produce and aquaponic system water and components. Duration: Year 1, Year 2 and Year 3. The current study will result in the characterization of the microbial populations of aquaponic systems (i.e., the system components including but not limited to rafts, solid support media, net pots, seedling media, ubiquitous biofilm, circulating fecal matter, water, etc.) and monitor these populations over time to increase the knowledge base with respect to this emerging integrated agricultural production technology. Additionally, aquaponic produce will be regularly tested for food safety microbes to ensure previously low detected levels of microbes are not artifactual, and clean, safe produce can be reproducibly produced in these systems. Additionally, as the technology matures, hand-held PCR machines will be incorporated into the testing protocols to determine if newer, faster technology for monitoring microbial endpoints can be used on-farm effectively to reduce time and costs for food safety certification. Currently three commercial aquaponic farms (Maris Garden cooperator Fred Lau, Oahu, Kunia Country Farms, cooperator Jason Brand, Oahu and Living Aquaponics INC. cooperator Zac Hosler, Hawaii) have agreed to be the private sector collaborators.
<P>Objective 3: Transfer developed aquaponic technology to appropriate end users via production of technical handouts (n=2) conducting demonstration workshops (n=3) and on farm field demonstrations. Duration Year 1, 2 and 3. Project work group members are to collaborate with State agencies, particularly HDOA and HDOH, along with private sector farmers to fulfill this objective. The information obtained during each year is to be summarized in at least one peer reviewed manuscript to be submitted to peer review journals for publication. Another output is the production of at least one technical handout each year that summarizes the research results in a user-friendly format. These technical handouts will form the basis for conducting at least one informational workshop each year. A hands-on training workshop is also a targeted outcome and planned for the second year of the proposed project.