In September, Health Canada gave the backing for the use by Canadian food processors of sodium diacetate as a preservative in meat, poultry and fish products. According to the food scientists, the preservative, when used in combination with sodium lactate, can inhibit the growth of Listeria monocytogenes.
The rules allow interim use of such preservatives in preparations of meat, meat byproducts, poultry meat, poultry meat byproducts and prepared and preserved fish products at a maximum level of 0.25 per cent of final product weight.
Last week CEO of Maple Leaf, Michael McCain said that Listeria exists in 100 per cent of all meat processing plants and it is impossible to eliminate it.
L monocytogenes is a pathogenic bacterium causing listeriosis, which is a rare but potentially lethal infection that can kill vulnerable people, such as the elderly and pregnant women, as well as those suffering from immuno-compromising diseases like cancer or HIV.
The pathogen can contaminate ready-to-eat meat and poultry during post-processing steps such as slicing, peeling and packaging.
Maple Leaf said that it identified listeria lurking deep inside two meat-slicing machines as the most likely source of the contamination, which caused it to shut down its Toronto processing plant in August.
The meat processor subsequently sanitized the facility, which led the government to permit the company to resume food production on 17 September. However, products are not allowed to leave the site until the Canadian Food Inspection Agency (CFIA) finishes its testing programme.
Maple Leaf said that since the plant re-opened 841 environmental samples have been taken, with one positive test result for listeria: “This is considerably lower than what normal practice would yield in listeria management programs.”
Officials are taking 60 samples from each production line every day, said McCain.
Maple Leaf said that it has developed a five-point plan for food safety, including a proposal to strengthen Canada's food-inspection system that would involve:
- Instituting tighter specifications for managing microbiological hazards such as listeria in the plant;
- Enhancing auditing practices to make sure the industry delivers on those high standards; and
- Developing a common approach to sharing data with the public on food safety as a means to increase transparency.
Adjustment of cleaning practices
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, bacterium such as 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.
The researchers said that they also evaluated the influence of different cooked meat juices including beef, pork, lamb, chicken and duck on the attachment of Listeria to 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.”