Cargill, which now joins an increasingly long list of meatpackers battered by food-safety mistakes, sharply expanded its US recall of ground beef potentially tainted with E. coli bacteria to 2.8 million pounds, the Wall Street Journal reported today.

The Agriculture Department, which has recently come under pressure from Congress to crack down on meat sanitation, also took the unusual step of indirectly forcing the closely held commodity-processing company to temporarily close the Milwaukee hamburger plant linked to 57 cases of food poisoning in several Midwestern states.

According to the report the department suspended its inspection operations at the plant, which is part of the Emmpak Foods business acquired by Cargill in August 2001. By federal law, only federally inspected meat can cross state lines.

Cargill spokesman Mark Klein said it is not clear when the Milwaukee plant, which employees 160 people, will be able to reopen and resume production.

Industry observers said the plant shutdown reflects Agriculture Department officials' concern that they did not get enough information from Cargill when deciding the size of the initial recall - 416,000 pounds - announced 27 September. Agency officials are also investigating whether Cargill was testing beef often enough for the pathogen. Klein claimed that Cargill officials acted properly in this particular case.

The food-poisoning outbreak was caused by O157:H7, a virulent strain of E. coli that causes bloody diarrhoea and dehydration. Contamination occurs when cattle manure, which harbours E. coli, is spilled onto meat during slaughter.

Cargill, Minneapolis, owns the nation's second-biggest beef producer, behind Tyson Foods.

As has been the case with most of the recent beef recalls, the problem is that as the product is fresh it has normally been consumed by the time the recall can be put into effect. The Cargill meat was produced in the third week of August.

It has been a difficult year for food safety. In July, an E. coli outbreak forced ConAgra Foods to recall 19 million pounds of ground beef produced by a Colorado meatpacking plant as far back as April. The extent of the recall, the second-largest of its type in US history, forced the Agriculture Department to acknowledge that E. coli contamination was a bigger problem than originally thought, and promised more pressure on meatpackers to quash the pathogen.