A survey by the Public Health Laboratory Service (PHLS) for the Department of Health has found that by 1991 the contamination level was one in every 650 eggs. By 1995/6, the level was one in every 700 eggs - despite the slaughter, between 1989 and 1993, of 2 million chickens with the aim of eradicating the disease on farms. The virulent S. enteriditis was found in one of every 1,320 eggs.
The surprising figures have been seen by the Government's Advisory Committee on the Microbiological Safety of Food (ACMSF), which has set up a working party to investigate the failure to control the disease.
Professor Richard Lacey, the microbiologist who first drew attention to the problem in the 1980s, said yesterday: "The reason it's happened is that they replaced the slaughtered flocks with new, infected flocks - they didn't take radical, curative steps. The epidemiology shows that it's still eggs which are causing salmonella poisoning."
The chairman of the ACMSF, Doug Georgala, told New Scientist magazine that the figures are "damn disappointing", adding that they represent "a drip feed of contamination into kitchens and restaurants that we have to tackle".
The Ministry of Agriculture, Fisheries and Food (Maff) countered yesterday that "actual levels of contamination in the breeding flock have come down". But a spokesman admitted that the problem of salmonella in eggs still remains, and that "the important thing is that all people have to do is cook the egg properly".
The PHLS records thousands of cases annually of salmonella food poisoning. Few cases are fatal, though people have died after, for example, sampling raw cake mix.
Professor Lacey said: "The problem is endemic now. But most people think that the problem has gone because they haven't had the advice reinforced about it. Some of the blame must fall on the last government. They would reassure people but didn't take radical action."
He also criticised the widespread practice, intended to kill salmonella, of injecting eggs before they hatch with an antibiotic to kill the bacterium. "All that does is select for antibiotic-resistant strains of salmonella," he said.
New Scientist suggests that the ACMSF may investigate rearing practices in Sweden, where fewer than 0.1 per cent of poultry are infected with salmonella. There, feed pellets are heated to kill bacteria, while imported chicks are quarantined for 16 weeks to ensure they have no disease before they are put into poultry houses.
In December 1988 the then food minister Edwina Currie sparked off a crisis in the egg industry when she said that: "We do warn people now that sadly most of the egg production in this country is infected with salmonella." Despite being correct, she was forced to resign.
n Animal welfare campaigners are urging egg farmers to help free millions of laying hens imprisoned in tiny cages.
Compassion in World Farming presented a report on the problem to the National Farmers Union in London yesterday, with the help of "Hetty" the giant former battery hen and a delegation of supporters. The document outlines the case against cruel battery cages and calls for them to be phased out.Reuse content