Biological Soil Amendments Get Very Specific Rules for Produce Safety
Updated: Nov 22, 2018
In follow up to last week’s article on water requirements of the Produce Safety rule, we are moving on to the next main section of the rule: Subpart F—Biological Soil Amendments of Animal Origin and Human Waste § 112.51.
Although the section includes a focus on those of both animal origin and human waste, FDA makes it very clear that human waste is, in most cases, not acceptable for use for growing covered produce. The one exception is that of sewage sludge biosolids used in accordance with the requirements of the Standards for the Use or Disposal of Sewage Sludge 40 CFR part 503, subpart D, or equivalent regulatory requirements. These include requirements for classifying the sewage sludge as Class A or Class B with respect to pathogens, site restrictions for land on which a Class B is applied, pathogen requirements for domestic sewage applied to agricultural land, and alternative vector attraction reduction requirements for sewage sludge applied to the land.
With that said, further reference to biological soil amendments in this article focus exclusively on those of animal origin. Again, we are posing the same questions that FDA included in the rule, with some further development and insights in the answers, as with the above explanation of the non-usage of human waste.
In the rule, FDA also set specific requirements for agricultural tea usage, with its definition based in part on the definition of compost tea by the National Organic Standards Board
“A compost tea is produced by combining composted plant and animal materials with water and a concentrated nutrient source such as molasses. The moisture and nutrient source contribute to a bloom in the microbial population in the compost, which is then applied in liquid form as a crop pest or disease control agent.”
FDA notes that certified organic farms would be able to comply with the agricultural team provisions while still meeting or exceeding organic requirements.
With that introduction, let’s move on to the Q&A (related only to animal origin, not human waste):
What signifies whether a biological soil amendment of animal origin is treated or untreated?
This biological soil amendment is considered to be treated if it has been processed to completion to adequately reduce microorganisms of public health significance. It is untreated if it has not been processed to this extent.
Agricultural teas are treated if its biological materials of animal origin have been so processed, and its water is not untreated surface water and has no detectable generic E. coli in 100 milliliters (mL) of water. It is considered to be untreated if any of these factors are not met or if it is made with biological materials that contain an agricultural tea additive (as based on the NOSB definition of compost tea additive).
In both cases, it is untreated if it becomes contaminated after treatment; is recombined with an untreated biological soil amendment; contains a component that is untreated waste that is contaminated with a hazard, or there is reason to believe it may be; or has been associated with foodborne illness.
How must I handle biological soil amendment of animal origin?
They must be handled, conveyed and stored:
In a manner and location such as to not become a potential source of contamination to covered produce, food contact surfaces, areas used for a covered activity, water sources, water distribution systems, and other soil amendments.
So as to minimize the risk of it becoming contaminated by an untreated or in-process biological soil amendment.
Any biological soil amendment that may have become contaminated must be treated as if it were untreated.
If all other requirements are met, agricultural teas may be used in water distribution systems.
What treatment processes are acceptable in the growing of covered produce?
As long as the resulting biological soil amendments are applied in accordance with § 112.56 (#5 below), you can use a scientifically valid controlled physical (e.g., thermal), chemical (e.g., high alkaline pH) or biological (e.g., composting) process, or a combination of these that has been:
Validated to satisfy the microbial standard in § 112.55(a) (#4a below); or
Validated to satisfy the microbial standard in § 112.55(b) (#4b below). Two examples of this are static composting that maintains aerobic (e., oxygenated) conditions at a minimum of 131oF (55oC) for 3 consecutive days, followed by adequate curing; turned composting that maintains aerobic conditions at a minimum of 131oF (55oC) for 15 days (which do not have to be consecutive), with a minimum of five turnings, followed by adequate curing.
What microbial standards apply to the above treatment processes?
The standards are specific to the pathogen:
monocytogenes – Not detected using a method that can detect one colony forming unit (CFU) per 5 gram (or milliliter, if liquid is being sampled) analytical portion.,
Salmonella species – Not detected using a method that can detect three most probable numbers (MPN) per 4 grams (or milliliter, if liquid is being sampled) of total solids.
E. coli O157:H7 – Not detected using a method that can detect 0.3 MPN per 1 gram (or milliliter, if liquid is being sampled) analytical portion.
Salmonella species – Not detected using a method that can detect three MPN per 4 grams of total solids (dry weight basis); and less than 1,000 MPN fecal coliforms per gram of total solids (dry weight basis).
What application requirements and intervals apply?
The biological soil amendments must be applied as specified, and according the intervals listed, in the following table:
What records do I need to keep?
For a treated biological soil amendment you receive from a third party, you must establish and keep documentation (such as a Certificate of Conformance) at least annually that:
The treatment process is a scientifically valid process that has been carried out with appropriate process monitoring.
The biological soil amendment has been handled, conveyed and stored in a manner and location to minimize the risk of contamination by an untreated or in process biological soil amendment of animal origin.
For a treated biological soil amendment you produce for your own covered farm(s):
Documentation that process controls (for example, time, temperature, and turnings) were achieved.
So as you can see, like the requirements for water in the produce rule which we discussed last week, the FDA has been fairly prescriptive in the requirements. For some, these may be a hard to meet, but at least we know what the FDA expects.
About The Acheson Group (TAG)
Led by Former FDA Associate Commissioner for Foods Dr. David Acheson, TAG is a food safety consulting group that provides guidance and expertise worldwide for companies throughout the food supply chain. With in-depth industry knowledge combined with real-world experience, TAG's team of food safety experts help companies more effectively mitigate risk, improve operational efficiencies, and ensure regulatory and standards compliance. www.AchesonGroup.com