Reuters reports that New Zealand’s Fonterra, the world’s largest dairy exporter, said on Saturday it had found bacteria which can cause botulismin some of its dairy products, prompting China to recall affected products.

New Zealand authorities said they were holding back some widely used infant formula products from supermarket shelves.

Fonterra said it had sold New Zealand-made whey protein concentrate contaminated with Clostridium Botulinum to eight customers, including food and beverage companies and animal stock feed firms, for possible use in infant formula, body building powder, and other products. None of its own branded products were affected, it said.

The Ministry of Primary Industries said Fonterra had told it the products in question were exported to Australia, China, Malaysia, Vietnam, Thailand and Saudi Arabia.

China, which imports most of its milk powder from New Zealand, asked domestic importers to recall any products which may have been contaminated by the bacteria, and ramped up scrutiny of New Zealand dairy products coming into the country.