New Zealand’s Fonterra, the world’s largest dairy exporter, on Saturday said it had found a bacteria which can cause botulism in some of its dairy products, prompting China to issue a recall of 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.

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

China, which imports the majority 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.

This is the second dairy contamination issue involving New Zealand’s largest company this year. In January, Fonterra said it had found traces of dicyandiamde, a potentially toxic chemical used in fertilizer, in some of its products.

The announcement comes as Fonterra is planning to launch its own branded milk formula in China, five years after its involvement in a 2008 scandal in which melamine-tainted infant formula killed at least six and made thousands ill.

Fonterra said that it was up to companies to announce recalls, adding that none had done so yet. It would not comment on the level of contamination found in the whey protein product.

“At this stage, no product recalls have been announced,” Fonterra said in a statement. None of its own branded products were affected, it said.

It also said that of the eight companies affected, three were food companies, two were beverage companies and three manufactured animal stock feed.

Chinese state radio said Fonterra was notifying three Chinese firms affected by the contamination.

China’s product safety agency said it had asked New Zealand to take immediate measures to “prevent the products in question from harming the health of Chinese consumers”.