* Codex bans animal manure for 'ready to eat' vegetables
* Still considering pig feed additive ractopamine
By Laura MacInnis
GENEVA, July 6 (Reuters) - An international food safety body set new rules on Tuesday on preparing bagged salads and said the chemical melamine that tainted Chinese milk is acceptable only in tiny amounts in infant formula and food.
The Codex Alimentarius Commission decided at its meeting in Geneva that animal manure should not be used to fertilise lettuce and other fresh vegetables sold "ready to eat" to avoid dangerous diseases.
Contaminated water must also be kept away from bagged produce that is not heat-treated, the Codex experts said, fixing new benchmarks that could change production and harvesting norms across the world.
"The problem is global," said Jorgen Schlundt, director of food safety and zoonoses at the World Health Organisation, who linked the use of animal manure in farming to disease outbreaks in the United States and elsewhere.
"It makes sense in a number of different production systems but when you are producing fresh salads that will be treated without heat treatment there is a problem," he said.
MINUTE LEVELS
Codex, a joint venture of the World Health Organisation and the Food and Agriculture Organisation,establishes food safety rules for importers and exporters.
In its discussion on melamine, the panel agreed that minute levels of melamine, the chemical used in making plastics, fertilisers and concrete, could be safe for human consumption, and set upper limits of 1 mg per 1 kg of powdered infant formula and 2.5 mg per 1 kg of other food and feeds.
WHO food safety expert Angelika Tritscher said melamine can be released in small quantities from a certain pesticide or when food comes into contact with hard plastic dishes, table-tops or some food processing machinery.
The human body can tolerate this "natural contamination" of melamine in small doses, unlike the intentional addition of the compound to Chinese milk that killed at least six children in 2008 and made some 300,000 ill, she said.
"Intentional addition of melamine to food to fortify protein content is by no means acceptable at any level," she said. "The purpose of these limits is to allow for the occurrence of natural contamination through approved uses."
The 2008 melamine crisis damaged the reputation of China's dairy industry and further sullied the made-in-China brand after a string of health and product-safety scares. China executed two people for their role in the scandal.
Tritscher said the Codex panel had not yet agreed whether to set a standard for ractopamine, a growth hormone added to pig feed that China and the European Union have alleged is unsafe, leading to a series of trade bans.
The drug, which promotes muscle development for leaner meat, is banned in the EU, and Brussels has banned imports of pork from Brazil, which uses it. Taiwan and Thailand also ban imported pork with residues of ractopamine.
China has banned imports of pork from U.S. producers found to contain residues of ractopamine. The United States has said it "strongly disagrees with China's assertions" and called for evidence to back up the ban.
"The discussions have been ongoing. It could still be made this week," Tritscher said. The Codex meeting ends on Friday.
A Codex ruling on ractopamine could set a benchmark for the World Trade Organisation to use to review countries' adherence to international trade agreements on food safety and sanitation, and help it arbitrate trade disputes over the growth hormone. (Editing by Jonathan Lynn and Tim Pearce)