British chocolate maker Cadbury says its tests have "cast doubt" on the safety of its Chinese-made products.
Cadbury says in a statement issued by its Singapore office that the tests "have cast doubt on the integrity of a range of our products manufactured in China."
It was not immediately clear if the tests revealed melamine, the industrial chemical at the center of China's recent milk scandal.
An Asia spokeswoman for Cadbury didn't immediately return a call from The Associated Press.
Last Friday, the list of companies facing potential recalls grew as reports of foods tainted with the industrial chemical melamine, which has been blamed in the deaths of four Chinese infants, spread to a widening range of products.
Food companies around the globe are rushing to assess their products and in some cases setting new strategies to prevent problems.
"We have to think about any processed food with milk or protein in it," said James Rice, a food industry veteran who is now China country manager for Tyson Foods Inc., the world's largest meat processor.
While his company is not affected, for others "that includes biscuits, cake mix, energy bars, anything that should have protein in it," he said.
Many food companies already were taking special precautions before Chinese milk suppliers were found to be adding melamine to watered-down milk to boost its apparent protein content. The chemical, which is high in nitrogen, can fool tests aimed at verifying protein levels. The compromised dairy products are blamed for sickening 54,000 children.
Some companies learned the need for extra diligence in China the hard way, during a spate of scandals last year from unsafe foods and toothpaste to melamine-laced ingredients in pet food.
But many continued to disregard the risks, said Jeremy Haft, a businessman who runs factories in China in a variety of industries, including medical products, clothing and building supplies.
"I don't think much was learned from the recalls of a year ago," said Haft, who has written of his experiences in a book, "All the Tea in China."
Tokyo-headquartered Lotte Group, a major snack maker, got caught up in the storm Friday after its popular chocolate-filled Koala cookies were recalled in Hong Kong and Macau because of melamine contamination.
Packages of the cookies, still on sale in Shanghai, list whole milk powder as an ingredient.
"We will look deeply into all the details of the manufacturing process," said Kayh Kim, manager of Lotte China Food's planning department in Beijing. "We really don't want to lose our customers' confidence."
In Tokyo, a company spokeswoman said Lotte products sold in Japan are not made with Chinese dairy ingredients.
Meanwhile, the Shanghai-based maker of White Rabbit, a popular vanilla-flavored toffee, said it stopped domestic sales after the Hong Kong government's Center for Food Safety said the candy contained more than six times the legal limit of melamine.
That followed White Rabbit recalls in Britain, Singapore, New Zealand and Australia.
When rumors of melamine-related recalls of Oreos and other sweets spread by phone text messages and on the Internet earlier this week, Kraft Foods Inc. hastened to reassure customers that none of its Oreo-brand products contain milk powder from China.
Oreo fillings contain no milk, while Oreo cookies with icing on them use milk powder from Australia, it said. "Regardless of where they are produced, Kraft products are always held to the highest quality and safety standards," the company said.
As they expand operations in China, targeting its potential market of 1.3 billion people, many foreign-brand food companies still rely heavily on local partners for quality control, experts say.