Low Listeria monoctytogenes levels in smoked salmon due to UK controls.

Listeria remains because of their ability to form environmental biofilms.

The UK Salmon Processors and Smokers Group (SPSG) said that the Food Standards Agency (FSA) findings showing low levels of Listeria in smoked fish in UK retail outlets is a result of their strict production controls.

The UK's food safety regulator said that more than 3,000 samples of ready-to-eat hot and cold smoked fish were analysed to check for Listeria monocytogenes, the main type of Listeria that causes illness in humans, between July and November 2006 from over 1,000 retail outlets in the UK.

While traces of Listeria monocytogenes were found in 302 samples, 99 per cent were within the legal limit for ready-to-eat foods, according to FSA.

Listeria is found naturally in the environment and can be present in a wide range of foods, from pâtés and soft cheeses to cooked sliced meats and smoked fish. The regulator said that three hot smoked fish samples (0.06 per cent) breached the limits for L. monocytogenes laid down in the Microbiological Criteria Regulations and the agency confirmed it took immediate action to withdraw the products from retail. In addition, the agency stated that no salmonella was detected in any of the samples tested but that it found variations in storage temperatures at retail ranging from -14°C to 13.3°C.

Controls in place: The SPSG, which comes under the umbrella of the UK's Food and Drink Federation (FDF), said that FSA’s findings come as no surprise to its members. “Food safety is our sector’s number one priority and members of SPSG have been working hard over many years to ensure the right production controls are in place,” claims the association.

Plant cleaning methods: Meanwhile, researchers from the University of Nottingham, in a recent study, claim that meat factories may need to modify their cleaning and disinfecting procedures according to the type of meat product being processed to prevent food poisoning outbreaks.

The team claims that biofilms, which are bacteria that form communities on surfaces, are much more highly resistant to cleaning products and antibiotics. In their opinion, Listeria's success in persisting in processing environments comes partly from its ability to form resistant biofilms, and partly from its tolerance to drying out, thus enabling it to survive on ‘clean’ surfaces. "We found significant differences between the ability of Listeria to stick to stainless steel surfaces at different temperatures, depending upon which meat was used,” said Professor Lisa Dodd. “Cooked duck juices at 25°C allowed the highest levels of Listeria attachment.”

Source: FSA, Foods Standards Agency.

Aporte: Guillermo Figueroa