A brand of soy-based formula feed has been recalled in Israel after three babies died and others were left seriously ill.
Remedia is popular among Orthodox Jews in Israel
The "Remedia" milk, sold as a Kosher fomula feed, was lacking a vitamin vital to brain development.
Thousands of Israeli babies are thought to have been given the feed, which is also thought to be popular in orthodox Jewish communities in the US.
Food giant Heinz, which owns a stake in the Israeli firm that manufactures it, was said to be "very concerned".
There is no firm proof yet that the absence of the vitamin, B1, from the feed was the reason behind the deaths and illnesses.
Two of the babies who died had other illnesses that might have contributed to their deaths, said doctors.
A deficiency of B1 in infancy can cause a condition called Beri-Beri, which can kill.
Parents of children given the formula have been urged to take their babies to the doctor for booster shots of the vitamin.
Robbie Steinberg, an Israeli health ministry spokesman, described the warning issued as a "precaution".
However, the ministry confirmed that legal action may be taken against the manufacturer, which is carrying out its own investigation.
Three are said to be critical, another seven are in hospital, and a further 10 cases are under investigation.
The formula is made for Remedia by Humana Milchunion, a German company.
A spokesman for the company admitted on Tuesday that tests have shown that the product contained at least 10 times less than the advertised quantity of vitamin B1.
Albert Grosse Frie said a production error was to blame. "We are talking here about a unique combination of unfortunate circumstances," he said.
Heinz is a majority stakeholder in Remedia, but a spokesman said that Remedia was not a Heinz brand although the company was "very sympathetic and concerned".
News of the possible risk triggered widespread alarm in Israel, with an estimated 20,000 people calling hotlines for more information, it was reported.
Spreading the news
Because news of the problem coincided with the Sabbath, during which the movements of Orthodox Jews are restricted, health authorities took the unusual step of hiring Arabs to drive to Orthodox neighbourhoods and spread the warning by loudhailer.
The Food and Drug Administration in the US is looking into the issue, as Jewish communities there also use Remedia.
It is reported that the formula has been taken off shelves in heavily Orthodox
Jewish neighborhoods in New York.
There are also reports that a baby who had been fed the milk substitute was in serious condition in a Boston hospital - although these have not been confirmed by an official agency.
A spokesman for the Food Standards Agency in the UK confirmed that Remedia was not marketed in this country.