Bacteriophage virus attacking a bacterium

What are bacteriophages and could they be a solution to bacterial contamination in food?

It seems crazy to suggest introducing a virus to make food safer, especially in the light of the Covid-19 pandemic, but there are viruses which have the ability to kill bacteria. There are already countries in Europe and further afield using these bacteriophages in food production to destroy bacterial contamination.

Bacteriophages can kill bacterial contamination

What is a bacteriophage?

A bacteriophage is a virus which can kill a specific host bacteria. This creates the potential for them to be used to destroy bacterial contamination that might be harmful to humans.

The bacteriophage uses the bacteria cells as a host to grow and reproduce. It injects its genetic material (nucleic acid) into the cell, where it can take over the operations of the bacteria and cause it to create shells, or phage coats for the new bacteriophage which are quickly filled with nucleic acid. The bacterial cell is then ruptured and destroyed as the new bacteriophage are released.

Bacteriophages can be inactivated by heat treatment of 30 minutes at 60°C, or by use of chemical disinfectants.

In some applications bacteriophages are currently considered a disadvantage such as in cheese making. A bacteriophage can attack and destroy the lactic acid bacteria required to turn milk into cheese resulting in a ‘dead vat’. You can find out more about the use of bacteria in dairy production here.

Where and how could bacteriophages be used?

There are two ways in which a bacteriophage could be used to increase food safety and reduce bacterial contamination. The first is to target bacterial pathogens which make humans ill such as ListeriaSalmonella or E. coli. Some of these are already in use in the USA, Canada, Australia, New Zealand and parts of Europe to treat a range of foods including poultry, red meat, ready to eat foods, fish, shellfish and processed fruits and vegetables. Where they are already in use, bacteriophages are often applied to food surfaces as a wash or spray.

The other way in which bacteriophages could benefit safe food production is to extend the shelf-life of foods by targeting spoilage bacteria. There is currently not enough research evidence to know how effective bacteriophages are at destroying spoilage bacteria.

What would need to happen before they can be used more widely in the UK and Europe?

Currently, no bacteriophages are approved at a European-wide level, though some countries have approved them under national rules. There are no bacteriophages currently approved for use in the UK. One problem with licencing them for use is over how they should be classified. If they are used for a one off ‘kill’ of bacterial contamination then they would be considered to be a food processing aid. If they have an ongoing effect which prevents reinfection then they would be considered to be food additives and would have different legislation requirements.

Current bacteriophage treatments use a mixture of several strains of virus to reduce the likelihood of resistant bacterial mutations. There needs to be an optimisation of the treatment process (an appropriate time and temperature) to achieve the maximum effectiveness against bacterial contamination. Until further research is undertaken and new guidance and legislation is introduced to oversee usage, it is unlikely that bacteriophages are going to appear in you food anytime soon.

Are there any health concerns?

Bacteriophages have been used in medicine to treat certain bacteria for decades before penicillin was discovered and are still used in some areas. However, further research is required to understand long term impacts of applying them to food. There are several safety concerns which need to be addressed including understanding whether there will be an increase in resistant bacterial mutations, and preventing release into the wider environment.

There are currently limited guidelines governing their use so there needs to be clarity regarding labelling requirements for foods treated with bacteriophages.

So, perhaps the use of viruses to reduce bacterial contamination in food is still a little bit like science fiction and it is unlikely to happen in the next few years. Bacteriophages is only one of a number of measures to reduce bacterial contamination to keep food safe for consumption, and would still need to be used in combination with great food hygiene practices. To learn more about other ways of preventing bacterial contamination in food and safe food production consider taking iQualifi’s online level 2 in Food Manufacturing.

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