The state Office of Cannabis Policy has issued its second recall of recreational cannabis and is urging people to throw away or return tainted products that were sold at 14 shops in the last month.

The recall affects preground flower, prerolls and blunts produced by Nova Farms with a strain called “Frosted Cookies.” Nova Farms is a Massachusetts-based company that has dispensaries in Maine and New Jersey.

The products failed the state’s mandatory microbial, yeast and mold tests and the Maine Office of Cannabis Policy is investigating the situation, according to a statement it issued Friday afternoon. The agency said it puts products on hold throughout its investigation to “ensure potentially contaminated cannabis was identified, isolated and removed from store shelves.”

The recall of the “Frosted Cookies” strain includes 1.5-gram and 3-gram single prerolls as well as 1-gram blunts packaged in fours, sold between Sept. 28 and Oct. 6. It also applies to 1/8-ounce, ½-ounce and 1-ounce preground flower; 0.5-gram, 1-gram, 1.5-gram, and 3-gram single prerolls; 0.5-gram prerolls sold in five-packs; 1-gram single blunts and 0.5-gram blunts sold in four-packs sold between Sept. 17 and Oct. 8.

Inhaling cannabis with unsafe mold, yeast or bacteria levels can cause sinus issues, allergies, headaches, flu-like symptoms and dizziness, the office said.

Maine’s first cannabis recall occurred on Sept. 10, when the Office of Cannabis Policy announced the recall of one strain of cannabis flower and three strains of prerolls, all of which were produced by Cannabis Cured, a cultivator and retailer headquartered in Fairfield.

John Hudak, director of the Office of Cannabis Policy, said at the time that the failure threshold for yeast or mold contamination is 10,000 colony-forming units per gram, “which is the threshold recommended by the American Herbal Pharmacopoeia for cannabis.”

Not every cannabis product on a store’s shelf has been individually tested. Rather, cultivators and manufacturers are required to submit “representative” samples of each batch. Sample sizes vary based on product and batch size and must be taken from multiple parts of the product. For cannabis flower, preroll and trim, for example, sample sizes range from 6.5 grams for a 2.5-kilogram batch and up to 22 grams for a 10-kilogram batch.

A contaminated batch hitting the market doesn’t automatically mean nefarious activity, Hudak said in September.

“This typically happens when there’s improper sample selection collection from the batches that are produced,” Hudak said.

This can happen accidentally because of improper training or intentionally, by not selecting a truly representative sample.

Yeast and mold are the most common contaminants that cause a sample to fail a test, according to Chris Altomare, founder and CEO of Portland-based Nova Analytics, one of the four licensed testing labs in the state.

Maine requires recreational cannabis be tested for filth and foreign materials, mold and mildew, harmful microbes, potency, homogeneity and cannabinoid profiles, moisture content, heavy metals, residual solvents, and pesticides. The state does not require medical cannabis to be tested.

Mold is the most difficult test to pass, Altomare said.

“It’s easy not to fail for pesticides – you just don’t use pesticides,” he said. “Mold is just a really prevalent thing. It’s hard to control.”

Further information about the recall Friday, including batch numbers, is available on the Office of Cannabis Policy’s website, under the “Resources” tab.

Defective products were purchased at the following Maine retail locations:

• Budz Emporium in Medway

• Camp Cannabis in Turner

• Columbia Recreational Marijuana in Columbia

• Foliage ME in South Portland

• Frosted Fire in Portland

• Gram’s Five & Dime Cannabis Co. in Newport

• Nova Farms Maine in Greenville Junction

• OMG Cannabis Co. in Portland

• Pot of Gold in Lebanon

• River Driver Cannabis Co. in Brunswick

• River Driver Cannabis Co. in Lisbon

• Royal Leaf Apothecary in Presque Isle

• Shipwrecked at 420 in Mechanic Falls

• The Joint.me in Portland

Staff Writer Hannah LaClaire contributed to this report.