HONOLULU (AP) — The Hawaii Department of Agriculture is investigating how hundreds of prohibited coffee-growing kits made their way to the state.

The kits, which contain African coffee seeds that are banned from being imported into Hawaii, were discovered on sale by a customer Tuesday on the island of Kauai.

The customer alerted University of Hawaii officials who referred the discovery to the Hawaii Department of Agriculture's Plant Pest Control Branch. Inspectors were dispatched to the store, and 12 kits were pulled immediately.

All but 10 of the 500 kits have been accounted for as of Thursday.

Officials say both the retailer and product distributor were informed the kits cannot be sold and both have been cooperative.

The Hawaii Department of Agriculture has a long-standing quarantine which requires that coffee plants and seeds for propagation be held in quarantine by the agency for a minimum of one year before being released for planting to help assure that the plants are not carrying any diseases or pests. In addition, imported coffee plants, plant parts including seeds or green beans and used coffee bags, require a permit and certification of specific quarantine treatment, KHON-TV reported (http://bit.ly/2s9xPl0 ).

"If there is an insect or plant disease, that's when it could become airborne and get into our coffee farms," said John McHugh, administrator of the department's Plant Industry Division. "We are especially concerned about Kauai, because it's the largest coffee farm in the U.S. with approximately 3,000 acres (12 sq. kilometers) of coffee."

Restrictions on coffee import were established to protect Hawaii's major coffee industry from the introduction of diseases and pests from other areas of the world.