Inspections across the country over the past month have found seven companies adding carcinogenic substances into their animal feed products.
The blacklist names five companies in northern Vietnam and two in Ho Chi Minh City, which were busted last week.
It’s not clear how the companies will be punished.
The companies were caught mixing their feed products with a substance to enhance leanness and a kind of industrial dye to give pork and chicken meat a more “eye-catching” color.
Both chemicals are banned in food production in Vietnam as they can be passed on to human consumers and cause cancer in multiple generations.
A statement from the agriculture ministry said police and market watchdog agents during the inspections have prevented hundreds of tons of expired and tainted animal feed from entering the market.
More companies will be inspected through February.
The ministry earlier this month fined two companies in Dong Nai Province neighboring Ho Chi Minh City a total of VND810 million (US$36,000) for using growth-promotion drug salbutamol in animal feed production.
Both were suspended for a month and forced to revoke and destroy all their products.