Sample Collection Protocol for Hemp, Cannabis and CBD Lab Testing

In this post:

  • USDA Hemp Sample Collection
  • USDA Rules on Sampling
  • Sampling Guidelines for Hemp Growing Facilities
  • Does the USDA include shipping procedures in its rules?
  • Is there cross contamination risk during sample collection
  • How do I choose a laboratory?

USDA Hemp Sample Collection Requirements Explained

On October 29, 2019 the USDA finally released rules for hemp production, sample collection and compliance testing, in response, ACS Laboratory developed the Hemp Clippings compliant hemp sample collection service for Florida farms. Following the release, the government entered the document into the Federal Registrar, where it remains open for public comment until December 30th. Once the comment period ends, final rules will be written and remain in effect through November 1st, 2021.

While these rules are not final yet, they have helped create the standards for individual state hemp programs. So if you are a hemp cultivator or are considering entering this booming industry, you’ll want to stay up-to-date with the USDA’s rules as they progress. In case you missed our first blog on the USDA hemp rules, check it out here to learn about THC compliance testing.

In this second blog below, read further to discover everything you need to know about how to collect samples for compliance testing and the best practices to prevent contamination.

USDA’s Rules on Sampling

One of the first questions that the USDA needed to answer was when must sample collection take place? The when was so important because THC content increases over time as the plant ripens, so samples must be collected close to harvest to reflect accurate potency. Along with the question of when, the USDA also determined who was responsible for testing. Below are the key takeaways from the interim rules document.

  1. Within the 15 days before harvest, you must employ an approved Federal, State, local law enforcement agency or other USDA designated official to collect samples. This varies from state to state. In Florida this must be a “Designated” Laboratory Certified Hemp Sampler that comes out to the grow to collect the samples.
  2. It is your responsibility as the grower to pay any fees associated with the collection process.
  3. You must provide the sampling agency representatives with unrestricted access during business hours to all of your hemp and other cannabis plants, “whether growing or harvested.”
  4. You must also allow access to all land, buildings, and other structures used for the cultivation, handling, and storage of all plants, and “all locations listed in the producer license.”
  5. You cannot harvest your cannabis crop prior to sample collection. Sample Collection is about 15 days before harvest.
  6. You must follow all procedures that are designed to produce a representative sample for THC content testing. (More on that in the description below< anchor text)
  7. During the scheduled sample collection process, you or an authorized representative of your grow operation must be present on-site.
  8. You can only submit samples to a qualified, DEA-licensed laboratory, like ACS, for THC compliance testing.

Sampling Guidelines for Hemp Growing Facilities

Along with the interim rules above, the USDA published a more in-depth document on sampling guidelines for hemp growing facilities. This document provides procedures for entering a growing area and collecting the “minimum number of plant specimens necessary to represent a homogeneous composition of the “lot.” These rules apply to greenhouse and outdoor grow operations.

Note that the sample collection procedure described below is specifically for THC compliance testing. The USDA does not explicitly describe a sampling procedure or requirements for safety related tests, such as heavy metals and pesticides.

How Does the USDA Define a “Lot”?

For the purposes of these rules, a lot is defined as a “contiguous area in a field, greenhouse, or indoor growing structure containing the same variety or strain of cannabis throughout.” In addition, “lot” refers to a whole of a product being sold to a single buyer at a single time. The actual plot of land in said “lot” is defined by you.

As the grower, you are responsible for reporting the field acreage of each lot to the Farm Service Agency before sample collection can occur. In Florida a lot is defined as a Plot.

What Equipment Do I Need for Sample Collection?

The USDA indicates the precise supplies you must use in order to comply with its sample collection procedures. These include:

  • Garden shears, which you must clean prior to and after each sample. Approved cleaning agents include rubbing alcohol, bleach, steel wool, and sandpaper.
  • Paper sample bags, which must be made of THC-free material and be sized based on the number of clippings per lot. Paper bags (as opposed to plastic) allow for air-drying during transport.
  • Security tape, to seal the sample bags.
  • Permanent markers, to write on the sample bags.
  • Sample collection forms
  • GPS unit for the inspector agent to audit your field measurements
  • Nitrile disposable gloves, to prevent contamination

What is the Procedure for Collecting Samples?

The USDA established clear procedures for collecting samples, which include surveillance of the growing area, time of sampling, and quantity of samples depending on the number of acres in your plot. While you cannot personally collect the samples, you must physically accompany the licensed sampling agent throughout the process.

You must also ensure that the plot you designated and submitted to the Farm Service Agency is accurate. Why? Because they will check.

Surveillance of the Growing Area

Make sure to take careful measurements of your field because the inspector will verify the GPS coordinates of the growing area and compare it to the measurements that you provided when outlining the “lot” in your FSA documentation. The inspector will also analyze the plants’ physical attributes to determine the degree of maturity and to confirm that the growing area contains all of the same variety of plants.

Field Sampling Rules

Within 15 days of anticipated harvest, you must arrange to have a USDA-approved representative or designated laboratory sampling agent (depending on your state) to conduct sample collection. You must monitor that official to ensure they adhere to the following guidelines:

What is the Required Process for Collecting Samples?

According to the USDA rules, sampling agents must “walk at right angles to the rows of plants, beginning at one point of the lot and walking towards another point on the opposite side of the lot.”

  • The inspector shall cut the minimum number of samples determined by acreage.
  • The samples must be taken from the flower or bud of the plant at “random but convenient distances.”
  • The inspector should avoid cutting too many samples from the borders of the field or greenhouse.
  • The inspector must cut just underneath the flowering part of inflorescence (the flower or bud), which is the top one-third of the plant.
  • The sample size must contain the appropriate volume needed for accurate laboratory tests. (Contact ACS for volume inquiries.)
  • The inspector must use a paper sample bag, which he or she must seal and record the sample number on.

What is the Process to Label Each Bag?

After the inspector seals each bag and records the sample identification number, he or she must label the bag with the following details:

  • Sampling agent contact information
  • Name and contact information of the producer
  • Producer hemp license or authorization number
  • Date of sample
  • “Lot” ID as provided by the USDA Farm Service Agency;
  • Any other information that may be required by States, Tribes, Law Enforcement Authorities, mail delivery services, customers or groups of customers

Does the USDA Include Shipping Procedures in Its Rules?

After reviewing the documentation, the team at ACS cannot find any language related to shipping procedures. Specifically, we do not see language that indicates whether or not the sampling agent will coordinate the shipping of your samples to a DEA certified lab or if you must arrange for sample pick up. At ACS, we will continue to monitor the latest news and let you know when the USDA publishes more information on shipping requirements.

Is There Cross Contamination Risk During Sample Collection?

The procedures above are detailed and will help guide you and the inspector to collect representative samples for THC potency testing. However, as a clinical laboratory, we at ACS feel it’s our duty to emphasize how cross contamination can occur and negatively affect your test results.

Dirty Equipment and Hands

If the sample collector touched a cannabis flower from a different plot that contained high levels of THC, he can cross contaminate your samples and skew the potency results. Additionally if he has bacteria or mold remnants on his hands for instance, he can pass these pathogens onto your plant. While the USDA does not dictate bacteria testing guidelines in this particular document, you must still keep your samples clean for safety testing.

Most states with an established Hemp program require this type of testing along with specific limits on what your product can contain. That’s why you want to be sure that the inspector’s hands are 100% clean before touching your crops.

Similar to dirty hands, unsanitized equipment can easily cause detrimental cross contamination in the form of THC, mold, bacteria and even heavy metals. That’s why you need to be sure that you thoroughly clean every piece of machinery after each use.

Moisture Buildup

Moisture buildup is another issue because it can attract pathogenic mold growth. Paper bags can help prevent this from happening by allowing the sample to breath, but be sure to properly seal the bag to prevent contamination. If improperly stored, samples may become compromised while en route to the testing facility.

How Do I Choose a Laboratory?

Once you’ve established a procedure and timeline for sample collection, schedule a test with a DEA licensed laboratory like ACS who you can trust to adhere to the highest safety and quality standards. If you live in Florida, you can request a courier service to transport your plant directly to the lab.

ACS professional drivers will pick up your samples and transfer them in a temperature controlled van to ensure they remain moisture-free and uncompromised. More details on the Florida Hemp Clippings services that ACS provides can be found on the website.

At ACS, we strive to provide the latest cannabis news as it unfolds, and we want to hear from you. We are an ISO/IEC 17025:2017 accredited, DEA Registered CLIA licensed Laboratory which means we can do human trials and participate in research studies, testing the effects of hemp. The future is in research.

Do you know of a clinical trial we may be missing? Do you need a resource to partner with you on your government backed study? Contact ACS today.

Contact us today to learn more about our award winning test procedures, our ISO certification and our 10+ years of medical testing experience.

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