Infection seems to have come from farm animals, but there is no evidence of further spreading.
The company’s decision comes after thousands of U.S. residents reported receiving unsolicited packets of seed from China, prompting all 50 states to issue safety warnings.
The 14 varieties identified include common ones, such as hibiscus, morning glory and lavender. Still, experts warned recipients not to plant them.
Agriculture officials in Louisiana, Kansas, Virginia and Washington State are urging residents not to plant the seeds, which were mailed in pouches featuring Chinese characters.