Shanghai entry-exit inspection authorities are investigating whether melamine-tainted baby formula found in the United States has been flown into the city.

The Shanghai Food and Drug Administration said baby formula in Shanghai was now safe.

The revelation that laboratory tests had detected traces of contamination in several major US brands of infant formula generated concern and confusion on Wednesday in America, with a national consumer's group and the Illinois attorney general demanding an FDA recall, according to The Associated Press.

As worried parents called manufacturers looking for guidance about the presence of melamine in US-made formula, the FDA called for calm, stating that the baby food was safe and the extremely low levels of contamination did not present a health danger.

Nestle's Good Start Supreme Infant Formula with Iron had two positive tests for melamine on one sample, with readings of 0.137 and 0.14 parts per million, AP said.

Mead Johnson's Infant Formula Powder, Enfamil LIPIL with Iron had three positive tests for cyanuric acid, at an average of 0.247 parts per million.

Separately, a third major formula maker - Abbott Laboratories, whose brands include Similac - told AP that in-house tests had detected trace levels of melamine in its infant formula.

Those levels were below what the FDA found in the other formulas, an Abbott spokesman said, and below any nation's safety guidelines.

"The levels that we are detecting are extremely low," Dr Stephen Sundlof, director of the FDA's Center for Food Safety and Applied Nutrition, told AP. "They should not be changing the diet. If they've been feeding a particular product, they should continue to feed that product. That's in the best interest of the baby."

Nestle, Mead Johnson and Abbott Laboratories manufacture more than 90 percent of all infant formula produced in the US.

Local supermarkets said yesterday that they had not removed the products of the three brands from shelves, officials said.

Wal-Mart said it was closely monitoring the government's action. "We don't know the specific batch number of the questioned products," said Hu Minghua, general manager of the supermarket. "Once we receive the stop-selling notice from the government, we'll stop."

Other supermarkets, such as Lotus, agreed. "Only products that have passed authorities' inspections can be sold at our market," said Xiang Jun, an official with Lotus.

The targeted companies all said their products in the Chinese market were safe. Abbott Laboratories said the baby formula on the Chinese market was all made from milk produced in New Zealand and Europe.

"All our products have passed the country's quality test," said Zhang Yongqing, an official with the company.

Nestle and Mead Johnson also said their products were safe and have passed authorities' inspections.

Four babies died in China and more than 54,000 were made sick after they were fed melamine-tainted baby formula.

(Shanghai Daily November 28, 2008)