Why “product Of USA” shiitakes probably aren’t.
[Shiitake mushroom-growing] Logs in China are made of Chinese sawdust and grain, inoculated with Chinese spawn, and loaded onto container vessels for a six- to eight-week trans-Pacific voyage. When the logs arrive in the U.S., they’re distributed across the country. Many of them end up in Kennett Square mushroom grow houses.
“In a week to 10 days, the mushrooms are picked and the logs get thrown away,” said Caputo, who called the mushrooms grown on Chinese logs “inferior.”
Because these mushrooms are harvested in the United States, they meet the USDA’s country-of-origin labeling requirement.
“They’re clearly not U.S. grown,” said Daniel J. Royse, professor emeritus at Penn State who specializes in mushrooms. “The regulations don’t make much sense to me. But the USDA says they’re OK because they’re classified as spawn. The logs actually are colonized substrate, they shouldn’t be allowed. The growers should get together to demand the USDA reevaluate the criteria.”