US consumer groups blamed a "business-friendly" Bush administration for lax food safety policies on Monday, in the wake of the largest US meat recall ever that prompted a 34 per cent drop in shares of Pilgrim's Pride.

Pilgrim's Pride, the number two US poultry producer, on Sunday recalled 27.4 million pounds of fresh and frozen ready-to-eat turkey and chicken products under its Wampler brand, after pulling 295,000 pounds of turkey and chicken products from the market last week due to listeria concerns.

The recall surpasses the previous record of 25 million pounds of ground beef set by Hudson Foods in 1997.

The company said the recall occurred after environmental tests at its Franconia, Pennsylvania, plant found a strain of listeria similar to the one identified in an outbreak in the US Northeast that has caused at least 23 deaths and 120 illnesses.

The company halted production at its Pennsylvania plant and recalled meat products it made between 1 May and 11 October. It said most of the turkey and chicken was purchased nationally at grocery stores and restaurants and already consumed.

US consumer advocates blamed the Bush administration for the massive recalls, saying hundreds have fallen ill because Washington eased food safety standards.

The poultry producer joins ConAgra Foods, Smithfield Foods and privately held Cargill in withdrawing massive amounts of meat in recent months because of fears they may be tainted with harmful bacteria.

The Pittsburgh, Texas-based company's stock tumbled $2.36 (€2.4), or 34 per cent, to $4.65 in mid-afternoon trading at the New York Stock Exchange. They ended the day's trading at $5.28.

Pilgrim's Pride said on Monday, however, that it did not expect the recall to have a material adverse effect on its financial condition.

"I think, with the market environment we are now in, any news regarding a company causes the reaction to sell first, ask questions later," said Richard Cogdill, the company's chief financial officer.

"We stand by our products that they are 100 per cent safe and wholesome."

Consumer groups blamed the Bush administration for not putting stricter food-testing regulations in place.

"There are proposed listeria regulations dating back to the Clinton administration that may have prevented this, but the Bush administration is sitting on it," said Karen Mitchell, executive director of Safe Tables Our Priority.

Last year, the USDA proposed rules, written by the Clinton administration, to require makers of ready-to-eat meats to test for listeria in their plants. The comment period ended in May 2001, but the Bush administration has yet to act on it.

"There is no excuse for the Bush administration to hold back needed improvements in food safety," said Caroline Smith DeWaal of the Center for Science in the Public Interest.

The USDA routinely tests products at meat plants for listeria, but separate industry testing is voluntary.

The Pilgrim's Pride recall was discovered by USDA while investigating a listeria outbreak that has caused at least 23 deaths, three miscarriages and 120 illnesses in the US Northeast. The company and USDA have said no illnesses could be linked to the recalled poultry.

The USDA and the Centers for Disease Control and Prevention have been unable to pinpoint the source of the Northeast listeria outbreak in Pennsylvania, New York, New Jersey, Delaware, Maryland, Connecticut, Michigan and Massachusetts.

The CDC has suspected turkey deli meat as one likely source. Despite more than 400 tests on lunch meats and deli products, the USDA has not been able to find the cause.

Eating food contaminated with Listeria monocytogenes can cause listeriosis, leading to miscarriages and stillbirths, as well as potentially deadly infections in those with weak immune systems.

At the Chicago Mercantile Exchange, live cattle futures prices were mixed due to concerns the huge recall may hurt consumer demand for meat. Live cattle contracts for October delivery closed on Monday off 0.325 at 68.150 cents per pound.

Pilgrim's Pride has voluntarily closed its meat processing plant about 25 miles north of Philadelphia, but hopes to reopen it on Wednesday. USDA said its inspectors must recertify that the plant meets federal food safety standards before it can return to operation.

"We are not going to open the plant until we are absolutely confident it's in the shape we want it in," Cogdill said.

Pilgrim's Pride said the amount of product covered by the recall was about 7 per cent of the company's annual turkey production and less than 1 per cent of its total poultry production.

About 2,500 cases of listeriosis occur each year in the United States. Listeria can be destroyed by cooking meat to a temperature of at least 160 degrees Fahrenheit (71 C).