Three new cases of listeriosis were reported in France just days after Dominique Gillot, secretary of state for health, announced that the outbreak had come to an end. This brings to 26 the number of people infected since December. Seven of them have died.
Ms Gillot said that most of the patients had eaten pig's tongue in aspic, but the producer of this French speciality has not been identified. Cross contamination by knives used to cut other products is probably involved.
The first alert was sounded at the end of January when contamination by Listeria monocytogenes was reported in pig's tongue produced by Sopar, a company in Meaux, near Paris. On 3 February, Austrian veterinary services notified France that a shipment of Sopar pig's tongue checked at the border was contaminated. The Sopar plant was closed down, and some 50 tonnes of its pork products were withdrawn from sale.
But it was only on 19 February, after reports on listeriosis appeared in the press, that health authorities published the list of regions that had been affected and issued a warning. They recommended that older people, pregnant women, and people with immunodeficiency should avoid eating pork products, particularly those produced by Sopar.
The Sopar plant resumed production with increased hygiene controls and was about to be closed down again when, on 22 February, the plant and all of its records were destroyed by fire. On 23 February health authorities announced the withdrawal from the market of all of the company's products, marketed under different brand names—Sopar, Délices de Suzon, Antoine Augé, and Val Heureux.
But two days later it was discovered that the strains of L monocytogenes identified in Sopar products were different from the strains that caused the epidemic.
The National Institute of Hygiene Surveillance is continuing its epidemiological investigation. Another investigation has been started to determine the origin of the fire at the Sopar plant and to ensure that the 50 tonnes of the Sopar pork products withdrawn from the market have been destroyed.
The institute's director, Professor Jacques Drucker, pointed out that not all the people infected with listeria had eaten pig's tongue and that the source of the epidemic could have been either different contaminated food specialities or contamination during distribution by knives that may have transferred bacteria from one type of food to another.
Such cross contamination is believed to have contributed to an epidemic in 1992, which affected 279 people, resulting in 63 deaths and 20 abortions.
Figure.
AFP
Checking the temperature of pork products in a French butcher”s: cross contamination is suspected in the recent listeria outbreak