"It was not intentional," Markus Faisst, chief executive of the butchers' cooperative EVGEDEM, told German newswire DPA.
Faisst said a negligent procedural error led to the byproducts from 170 cowhides - waste from a slaughterhouse - being labeled as food for humans instead of as so-called "K-3 material" suitable only for animal feed. The company shipped the hides from its base near Würzburg in Bavaria to the neighbouring state of Baden-Württemberg.
The public prosecutor's office is investigating the company on suspicion of improper use of commercial documents, the Bavarian State Office of Health and Food Safety announced on Wednesday. A routine inspection by the district veterinary office turned up the problems, health officials said.
Health officials said the cowhides do not pose a public health risk. Other kinds of K-3 material include hooves, horns, pig bristles and feathers.