Bacteria eating viruses help fight food pathogens: EFSA study

By MIke Stones, 18-May-2009

“Bacteria eating” viruses, known as bacteriophages, could be an effective way of eliminating specific food pathogens, according to a recent report from the European Food Safety Authority’s BIOHAZ Panel.

Some bacteriophages, under specific conditions, could be used to eliminate specific pathogens in milk and meat products, concluded the study.

The panel, which deals with biological hazards in the field of food safety and food-borne diseases, noted that bacteriophages tend to persist longer than their hosts and behave as inert particles in the environment.

But, their long-term antibacterial activity is reduced on dry surfaces and their persistence in food varies with each bacteriophage, and with the conditions of application. Factors include: Dose, and physical and chemical factors associated with the food such as pH and moisture levels. For example, refrigeration temperatures improve the persistence of bacteriophages on the surfaces of meat and dairy products.

Environmental factors

However, after reviewing peer-reviewed scientific literature, the panel was unable to conclude whether or not bacteriophages can protect against bacteria in cases where the food becomes re-contaminated. The effectiveness of bacteriophages against re-contamination of food may vary according to the characteristics of the food, the type of bacteriophage and how it is used, and environmental factors.

The panel recommended further research to gauge the persistence of bacteriophages in foods and their ability to prevent recontamination with bacterial pathogens. Research should focus on specific combinations of bacteriophages, pathogens and foods, it said.

The panel’s study stemmed from a request from European Commission for the European Food Safety Authority (EFSA) to advise on the use of bacteriophages on food of animal origin. It was asked to particularly focus on the mode of action of bacteriophages on carcasses, meat and dairy products.

Bacterial cells

Bacteriophages occur in a broad range of habitats in nature and can be isolated from meat, milk and derived products. They replicate best on growing bacterial cells, but can also reproduce on cells which are not in a growing phase.

The US Food and Drug Administration first approved the use of bacteria eating viruses as food additives in ready-to-eat meat and poultry to protect against Listeria three years ago.