Listeriosis

Posted by Andrew Wadge on June 6th 2007 in Science, safety and health

Some of you may have seen that last week the Health Protection Agency reported an 80% increase in the number of UK cases of listeriosis, compared with 2006. 

Listeriosis is caused by the bacterium Listeria monocytogenes. This bacteria is all around in the environment and may contaminate ready-to-eat foods when they are being processed in the factory. 

It is one of the five indicator microorganisms that the Agency uses to monitor the progress of our foodborne disease strategy.

While healthy people are not usually at any risk of illness from any increase in number of reported cases is a concern, especially when the effects of the disease can be very harmful. 

The pattern of disease has also changed since the 1990s, when it was mostly associated with pregnant women to now where approximately 70% of cases are over 60 years of age.

This suggests that the epidemiology of the disease may have changed together with a possible change in the biology of the bacteria and there is a need to find out more about this.

What are we doing? Well the Agency, together with the local authorities continue to investigate incidents of Listeria moncytogenes in ready-to-eat foods where the levels found exceed the legal requirements.

We continue to provide advice to those groups most at risk of illness, and the Agency advicses for vulnerable groups, such as pregnant women, to avoid consuming soft mould ripened cheeses, pates, and raw meat and fish.

We are also in the process of commissioning research to try and find out why there has been a change in epidemiology of listeriosis by investigating a whole range of different factors that may be responsible for the increase in cases.

This project should begin later this year and any findings will be fed back to the independent Advisory Committee on the Microbiological Safety of Food to consider.

Incidentally, this committee is meeting tomorrow and will have the opportunity to provide views on the reported number of cases and methods of control.

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Re Listeriosis

Posted by Andrew Wadge on 14/06/2007 - 16:20

Ewen, thanks for your comments. It's a very good point that we can't treat older people as a homogenous group - there are definitely differences between people in their 50s and people in older age groups, in terms of health, lifestyle and also attitudes.

Equally, some 50 year olds can be more vulnerable to foodborne diseases than some 80 year olds - age is certainly not the only factor to consider. We will be bearing this in mind in our efforts to identify those older people that we most need to target with advice and guidance, whether they are living independently or in residential care.

Listeriosis

Posted by Ewen Todd, Food Safety Policy Center, Michigan State (not verified) on 07/06/2007 - 17:54

This is indeed interesting. We also suspect that lack of compliance is a major reason for the listeriosis cases especially with deli meats, although case control studies show foods not traditionally suspected like melons and hummus may also be vehicles of transmission. Most assessments treat elderly people as one large at-risk category but there are clearly differences between the ages of 55 and 99 for immunity and underlying diseases. This is worth exploring further to subdivide this population into different risk categories.

I am in the process of organizing an international conference on harmonization of regulations concerning L. monocytogenes and have formed an advisory committee to plan the agenda. Maybe someone from the FSA would like to participate on the Committee.