The company, which produces about 7.2 million hogs a year, "will no longer sell certain whole pork products into California due to California's Proposition 12," spokesman David Eaheart said.

The measure, approved by voters in November 2018, is slated to take effect 1 January, reported Reuters.

Supporters say it will make food production more humane by setting minimum space requirements for calves raised for veal, breeding pigs and egg-laying hens. It also forbids the sale of raw veal, pork or eggs from animals enclosed in too little space.

Opponents in the US meat industry argue that enforcement will hurt producers and consumers by increasing food costs, and violate the US Constitution's Commerce Clause by requiring out-of-state producers to comply or face the sales ban.

California represents about 15% of the US pork market, according to the trade group the National Pork Producers Council. The meat industry estimates it would cost pork producers billions of dollars to convert barns to meet Proposition 12 standards, the council said.

Hormel Foods Corp said it is preparing to fully comply with the law.