The newly revised Produce Rule is drastically different than the original provisional rule. Growers are encouraged to comment on the changes, and respond to several questions that the FDA has about water microbial requirements. Comments are due by December 15th.
The Produce Rule previously required farms to sample surface water used for irrigation (water that would come in contact with the harvestable portion of the plant) every seven days. For example: irrigation pond water that is used for overhead irrigation of blueberries or pond water that is used in pesticide application sprays on tomatoes. This requirement has changed, growers will need to create a baseline survey of the surface water and conduct annual sampling of that water. To create the baseline survey a farm using surface water would need to sample a minimum of 20 times over a two year period. The geometric mean will need to be calculated from these 20 samples to identify the water profile. Each year after, the water must be sampled a minimum of 5 times to verify that the water profile has stayed the same. The FDA has set a statistical threshold value of 410 colony forming units (CFU) of generic E. coli/100ml water and a geometric mean of no more than 126 CFU generic E. coli /100ml water. If there is a significant change in the sample results from the profile identified by the baseline survey bacterial die off rates (described below) will need to be calculated and modifications to the irrigation system should be made when necessary. Additionally a new profile will need to be created, requiring 20 additional samples over a two year period. The rule requires, even if the profile has not changed in the annual sampling, that a new profile be created every ten years.
Ground water used for direct water irrigation or pesticide use is also subject to water testing. Ground water testing will be required four times the first year, close to or at harvest to create the baseline survey. Irrigation and pesticide use water sampling results would allow the use of water with no more than 126 CFU of generic E. coli per 100 ml. Water sample results above 126 cfu/100ml would require inspection and treatment of the well. Once the ground water baseline survey shows levels below the 126 CFU/100ml the requirement for sampling drops to once per year.
Ground water used during or after harvest must meet a zero generic E. coli result. This includes water used for product post-harvest water, sanitation, agricultural teas and sprout irrigation.
In addition to the sampling requirements the FDA is proposing to include bacteria die off rate calculations. This would allow growers to use the time period between last irrigation and harvest, and between harvest and end of storage to evaluate acceptable generic E. coli numbers from their water source.
The FDA will release guidance documents and resources to assist growers with the necessary calculations to determine baseline surveys and die off rates after the final rule is published.
Questions to think about:
How often do you irrigate with surface water and how would sampling 20 times over a two year period affect your operation?
Do you think that there should be maximum levels of E. coli allowed in addition to the baseline sampling?
Do you think that growers who are involved with surface water sampling should be required to keep records of the sampling and the results? (examples include the results of an irrigation system inspection, water sampling results, modifications made to irrigation systems etc.)