Plant production and maintenance

For companies growing large-scale cannabis crops, plant tracking is essential. Government regulations, including newly adopted Canadian legislation, require companies to keep records of each and every plant in their inventory.1 Labeling each plant using tags made of film that can wrap around the stem of the plant is preferred over using soil tags or labeling pots. Labeling the plant itself has two distinct advantages: it makes labeling easy for hydroponically-grown plants and, when potted plants need to be moved or repotted, it ensures that the label will move with the plant. However, if you’re also labeling cannabis pots, the labels should be resistant to water, humidity, and UV light, depending on the growth conditions of your plants.

Metal plant racks used to grow and dry cannabis plants, containers (e.g. bags and glass bottles) for dried leaves, and other equipment, such as UV lamps and hydroponics racks and reservoirs, also require labeling. Like pot labels, these should also resist water, humidity, and UV light, with labels specifically designed for metal surfaces also available.

To efficiently track all your plants and equipment, labels should be paired with radio-frequency identification (RFID), providing “seed-to-sale tracking”. RFID labels provide the best method of recording and tracking everything in your nursery, as they do not need to be individually scanned and can incorporate additional information, such as the strain, the ID number of the plant, as well as the license number of the housing facility. You can also use barcodes to track your inventory, with a variety of 1D or 2D barcodes that can be generated using printing software (e.g. BarTender).

Cannabis extraction

Cannabis extraction is used to generate a variety of cannabis products, from oils to oral sprays and pills. There are many different extraction methods, including alcohol extraction, CO 2 extraction, and propane or butane extraction, each with its own labeling pitfalls. Alcohol and propane/butane extraction exposes glassware and container labels to alcohols and volatile liquids, which can degrade the label’s adhesive and smudge the print. CO 2 extraction provides a different obstacle, as CO 2 needs to be cooled to a temperature of –57°C (–70°F), requiring the label to withstand low-temperature conditions. Thus, depending which method you use to extract cannabinoids and terpenes with, you will require labels that are either deep-freeze or chemical-resistant. Using a thermal-transfer printer with a resin ribbon can also further safeguard your printout, though using a digital printer (inkjet or laser) with self-laminating labels will also protect against smudging or fading. Direct thermal printing is not advised for these applications as the label may turn entirely black upon exposure to any harsh solvents, like alcohol.

Quality control testing

Before cannabis products can be sold, they must be rigorously tested. Firstly, the content of the active cannabis ingredients must be assessed. This is usually performed by taking a sample of cannabis extract and analyzing its components, including cannabinoids and terpenes, via high-performance liquid chromatography (HPLC), liquid chromatography with mass spectrometry (LC-MS), gas chromatography (GC), or thin-layer chromatography (TLC). These processes require the use of several harsh organic solvents, like methanol, hexane, acetonitrile, and chloroform, all of which can affect the integrity of your label’s adhesive and cause your printout to fade or rub off entirely.

Cannabis samples also need to be tested for potentially harmful contaminants, including pesticides, heavy metals, and residual solvents. Like cannabinoid analysis, the presence of pesticides and solvents can be tested for using either LC-MS and GC-MS, while heavy metals are commonly detected with inductively coupled plasma mass spectrometry (ICP-MS), which exposes your tubes (and labels) to strong acids, like nitric acid and hydrochloric acid, during sample preparation. For these applications, chemical-resistant labels with a thermal-transfer printout are the best option. Note that headspace analysis, where a syringe is used to pull out fumes released when the samples are heated, is frequently used to detect residual solvents in cannabis samples, eliciting the need for syringe labels as well.

The presence of microorganisms is another crucial factor that needs to be tested for prior to distribution. Poisonous molds, E. coli, and Salmonella can all grow in dried cannabis flowers and leaves if the moisture levels are too high. These organisms can be detected by two methods: microbial culture analysis and quantitative PCR (qPCR). Using petri dishes, microbial cultures can be grown from cannabis samples to determine the number of colonies formed by each organism. qPCR can also be applied to measure the presence and quantity of microorganism-specific DNA sequences in a sample. While petri dishes and qPCR plates with skirts provide ample room to affix microplate labels, qPCR plates without skirts do not. The best available product to label high-profile PCR plates without skirts is PCR-TagTrax™, which can efficiently tag PCR tubes, 8-tube strips, and microplates with more information than any other labeling method.

Product packaging and distribution

There are strict legal requirements for packaging labels that must be adhered to before inventory can be shipped. Canada has stipulated that packaging labels must contain a standardized cannabis symbol (in red and white), health message warnings (in black with a yellow background), and the cannabinoid content (in bold), all of which must appear in sans-serif font. Each package must also include a tamper-evident label.2 There are similar rules throughout the United States for states where recreational cannabis use is legal. For instance, Colorado also has specific rules regarding the labeling of cannabis packages, with regulations on the size of the cannabis warning logo and text. They also have regulations on the labeling of edible products, with each package requiring information about the ingredients, refrigeration, serving size, and expiration date.3 However, these regulations vary from state to state, including the imagery of the warning symbol, which differs in Oregon, Colorado, and Washington.4

With the legalization of cannabis in Canada as well as 11 American states, with another 23 permitting the sale of medicinal marijuana, business has never been better for companies that grow, test, and distribute the medicinal plant. With a market that’s valued at $31 billion in Canada alone, in addition to strict government laws and regulations, it pays to properly track your cannabis plants, samples, and products by investing in high-quality labels that won’t fail, even under the most stringent conditions.

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