This Is AuburnElectronic Theses and Dissertations

Assessing the Scientific Basis of the Food Safety Modernization Act Produce Safety Rule and Microbial Quality of Water Used to Grow Produce in Alabama




Gradl, Janet

Type of Degree

PhD Dissertation


Poultry Science


Small farms are a growing part of the fresh produce market. In Alabama, 93 percent of farms are defined as small and 2 percent of agricultural sales were from fresh produce in 2016. Only 1.3 percent of produce farms in Alabama are GAP certified. Alabama Agricultural Experiment Stations (AAES) conduct research and demonstrate technologies before they are adopted by commercial growers. For this reason, they were used to represent small growers. The 2016 Final Produce Safety Rule (PSR), currently scheduled to be implemented in 2018, will require growers to follow a new set of practices during growing, harvesting, packing, and holding of fresh produce. Among other criteria, the PSR establishes standards for water that directly contacts produce pre- and post-harvest. AAES can aid growers with PSR implementation. The objectives of this study were to (1) assess the scientific basis of the agricultural water provision of the PSR, (2) determine the average E. coli presence in agricultural water used to grow produce during a growing season at three locations across Alabama, and (3) determine which food safety practices a sample of AAES farm managers implement. Data from this study will determine the baseline level of food safety practice and knowledge of a sample of PSR-exempt growers, as well as the microbial quality of water used in produce production and harvest in relation to the PSR standards. All scientific studies cited in the Federal Registrar in support of the PSR were categorized and assessed for how well they matched the FDA’s claims. It was found that overall, the FDA made a good faith effort, given the time and resources, to base the water provision of the PSR on “sound science.” There are gaps in the literature, but the FDA was required to publish the Final PSR within a timeframe before additional baseline funding could be established. Ground, county, and surface water were sampled from seven sample sites in three different geographical areas of the state over a four-month growing season. Under the PSR, growers must choose a water quality testing method that vary in cost, feasibility, and ease of use. Generic E. coli presence was enumerated with three methods equivalent to EPA Method 1603: EPA Method 1604 (MI), Hach Method 10029 (mColiBlue24), and EPA 1103.1 (mTEC). There was an average geometric mean (GM) of E. coli in the two surface water sources of 20 and 6 CFU/100 mL. There was no detectable E. coli in the ground and county water sources. The mTEC produced significantly different E. coli counts than the mColiBlue24. Next, a survey was sent to AAES farm managers across the state. From the 8 responses received, it was found that none had a food safety plan or had conducted an environmental microbial safety risk assessment; there were food safety risks such as wildlife, domestic animals, and use of untreated soil amendments close to the growing areas; only one farm had trained their workers in food safety practices; and one other farm tested their irrigation water. Although all water sources met the PSR criteria, the presence of food safety hazards indicates that risk assessments should be conducted. This study provides opportunities for AAES and growers to review implementation of the PSR and optimize training. Both parties would benefit from opportunities like on-farm safety demonstrations to fill the current gap in knowledge.