HC Deb 09 March 1990 vol 168 cc890-2W
Mrs. Gorman

To ask the Secretary of State for Health how many cases of food poisoning in 1989 were associated with the consumption of eggs; and in how many of those the vehicle of infection was suspected or known to have been home-made mayonnaise.

Mr. Freeman

Most cases of food poisoning are sporadic and cannot be linked to a particular food vehicle with any confidence. In 1989, salmonella was the causative organism of 42 outbreaks (involving 549 people) in which eggs, or egg-containing foods, were the suspected vehicle of infection. A further five outbreaks were due to Bacillus cereus. In four of these egg was a component of egg fried rice, and since B. cereus is particularly associated with rice it is likely that rice was the source. In the fifth an omelette was reported as the vehicle; one of the constituents other than the egg may have been the source. In three of the 42 egg-associated outbreaks (involving 96 people) due to salmonella, the food suspected was mayonnaise made from fresh shell eggs.

Mrs. Gorman

To ask the Secretary of State for Health how many outbreaks of food poisoning have been associated with eggs in each of the last five years which involved mayonnaise, where human sources of contamination have been implicated.

Mr. Freeman

In no outbreak reported to (or investigated by) the PHLS communicable disease surveillance centre in the last five years (1985–89 inclusive) in which mayonnaise was suspected has a human source of contamination been implicated.

Mrs. Gorman

To ask the Secretary of State for Health how many outbreaks of food poisoning have been associated with eggs in each of the last five years where the causative organism was not salmonella.

Mr. Freeman

Eggs or egg-containing foods were the suspected vehicle of infection in 10 outbreaks due to organisms other than salmonella in the last five years (1985–89 inclusive). Five of these outbreaks occurred in 1989 and, as described in my previous answer today, in four of these egg fried rice was suspected, with rice the probable source of the infection. In the fifth, an omelette was the vehicle.

Mrs. Gorman

To ask the Secretary of State for Health if he has any evidence of any cases of food poisoning being caused by the consumption of pasteurised liquid egg within the last five years for which figures are available.

Mr. Freeman

In no outbreak reported to the PHLS communicable disease surveillance centre in the last five years (1985–89 inclusive) has pasteurised liquid egg been suspected as the vehicle of infection.

Mrs. Gorman

To ask the Secretary of State for Health what action he intends to take in respect of the Exeter public health laboratory report to the effect that eggs when fresh are unlikely to constitute a significant potential health hazard.

Mr. Freeman

Research carried out by the Exeter public health laboratory showed that eggs laid by two infected flocks were intermittently infected with less than 10 organisms of S. enteritidis phage type 4 per egg at point of lay. However, a substantial number of outbreaks of human salmonellosis where the source of infection was identified have been caused by eggs. In the examination of shell eggs, the numbers of salmonellas are not routinely estimated. This is because the presence of even small numbers is regarded as a potential health hazard. During limited special investigations, two shell eggs containing many hundreds of salmonellas have been found. Research continues to investigate the factors which govern the multiplication of salmonella in shell eggs.

Meanwhile, the chief medical officer continues to advise the public not to eat raw eggs or uncooked foods made with them, and for vulnerable people to consume only eggs which have been cooked until the white and yolk are solid.

Mrs. Gorman

To ask the Secretary of State for Health what assessment he has made of the reasons why the number of laboratory-confirmed cases of food poisoning reported to the communicable disease surveillance centre for the first six weeks of the year are at a record level.

Mr. Freeman

Fluctuations in single weekly reports of salmonella isolates to the PHLS communicable disease surveillance centre are not a guide to long-term trends. Any weekly reporting system will inevitably be subject to short-term anomalies. This occurred during the postal strike of 1988, and was also the case for weeks 2 and 3 of this year when delayed reporting and a backlog of data entry gave rise to an artificial increase. The apparent increase in reports for this year over last is likely to decline as the anomalous weeks 2 and 3 contribute a smaller proportion of the total.

It is to permit analysis of trends that the public health laboratory service and the state veterinary service has introduced recently the quarterly publication "Update on Salmonella Infection". The figures published in this for 1986–89 indicate a recent levelling-off in the incidence of Salmonella enteritidis phage type 4 infections, which account for the greatest number of all human salmonella infections. The volume of laboratory work undertaken by the PHLS division of enteric pathogens for the beginning of this year confirms this trend.

Mrs. Gorman

To ask the Secretary of State for Health what assessment his Department has made of the risk to health from meat birds which have been infected with salmonella enteritidis PT4 being sold to domestic consumers where they might be undercooked, recontaminated after cooking or, in their raw state, provide a source of contamination which might, directly or indirectly, contaminate other foods.

Mr. Freeman

It is well established through microbiological surveys that poultry are frequently contaminated with salmonella. Consumers are well aware of the need for good hygienic handling of poultry meat in the kitchen and of the need for thorough cooking. The current wide circulation of the Government's "Food Safety" leaflet has reinforced these needs.

Mrs. Gorman

To ask the Secretary of State for Health whether he has issued any specific guidance to caterers for the production of home-made mayonnaise, so as to prevent the multiplication of salmonella or other organisms introduced into the mix by whatever means; and if he will make a statement.

Mr. Freeman

On 26 August 1988 caterers were first advised to use pasteurised egg for uncooked egg dishes since such commercially produced products, manufactured with pasteurised egg, had not been implicated as a source of infection. This was reiterated on 21 November and again by the Chief Medical Officer on 5 December 1988. This advice endorsed the egg industry's own code of practice on the hygienic handling and use of eggs.

Mrs. Gorman

To ask the Secretary of State for Health whether his Department has assessed the risk to health from eating poultry meat derived from hens which have been infected with salmonella enteritidis PT4, after the hens have been cooked for three hours at 97 deg C in industrial cooking equipment.

Mr. Freeman

Salmonella enteritidis PT4 can be destroyed by appropriate heat treatment.