Salmon susceptible to resistant bacteria

IRISH smoked salmon has shown itself to be particularly susceptible to a dangerous form of food poisoning bacteria.

A study commissioned by the Food Safety Authority found that the same strain of food contaminating listeria appeared in two-thirds of infected salmon.

Preliminary research suggested the manner in which the strain evolved in Irish smoked salmon makes it capable of staying alive after the product hits the shelves.

Deputy chief executive of the FSAI, Alan Reilly says the study should remind people how important it is to pay attention to use-by dates printed on smoked salmon products.

He said: “Listeria is an extremely dangerous bug and, because it can be a killer, is among the more serious contaminants we come across.

“Because listeria is so difficult to get rid of, it is an absolute problem once it gets into a plant or premises. What we can see now is that listeria can survive in cold temperatures and it can withstand chilling which makes it ecologically unique, and that is why paying attention to shelf life is very important.”

Researchers at University College Dublin, Cork Institute of Technology and Waterford Regional Hospital carried out the experiments on smoked salmon identified by the FSAI to be carrying bacteria.

Their work is carried in the latest volume of the International Journal of Hygiene and Environmental Health and shows that the same type of bacteria was appearing in fish from 60% of processing plants.

It said: “(Testing) identified a single dominant strain that accounted for 65% of bacteria grown from smoked salmon and this strain was present in product obtained from three out of five manufacturers.

“In Irish smoked salmon this strain may have adapted and be capable of persisting in this food product.”

Previous research has proven how listeria monocytogenes can cause serious diseases such as meningitis.

In its conclusions, the research team said its work further strengthened the case that a single type of listeria either persisted throughout food smoking or within the factories.

The deadlier 4b class of bacteria, to which humans are most susceptible, was prevalent in 8% of cases.

A number of Irish smoked salmon producers were contacted but each referred the matter to the Department of the Marine who conduct all food safety tests.

Cork based Department of the Marine inspector Pat Scanlon said that even allowing for the existence of listeria, the testing it carries out is there to ensure complete consumer confidence.

He said: “We are obliged by contract to take samples and carry out tests on all smoked salmon plants at a minimum of a least once a month and we are audited by three different organisations on that.”