Ozone and vapour proving to be best in class for food pathogens

The results of a three-year long research project at Campden BRI indicate that commercially available techniques such as ozone and vapourised hydrogen peroxide have a different mode of action on microbial cells and proved decisive in terms of improving disinfection in hard to reach areas such as pipes and drains as well as airborne microbes.

The growth in demand for ready-to-eat and chilled food products coupled with a glut of recent studies identifying persistent strains of bacteria within a food manufacturing environment has led to an interest in novel methods of microbe inhibition in the food and drink industry.

Unknown quantity ​

While disinfection methods based on ozone and vapourised hydrogen peroxide have proved effective in health care environments, their use in food factories has been minimal, and Campden BRI said these techniques had little microbiological assessment while their practical operation and benefit in the food and drink processing sector has not been quantified.

Karen Middleton, technical contracts manager at the Food Hygiene Department at Campden BRI told this publication that Listeria monocytogenes​​​and E.coli​​were the target pathogens of the whole room disinfection research project, which was selected out of several topics proposed to its food processing membership as potential areas of study three years ago.

Trials with suppliers​

The team collaborated with leading UK based suppliers such as Steritrox, whose Radical division produces ozone to eradicate contaminants in food processing environments as well as Bioquell, which supplies hydrogen peroxide vapour technology for bacteria elimination in food production facilities.

The Campden team determined that vapours and gases have several advantages as they can effectively penetrate every part of a room, including sites that might prove difficult to gain access to with conventional liquids and manual disinfection procedures.

Chemical fogging requires a sufficient quantity of chemicals to be deposited on all food contact surfaces and the surrounding environment in order to be effective, said Middleton, and it has minimal effect on vertical surfaces and the underneath of equipment, unlike ozone and vapourised hydrogen peroxide techniques which their research showed had contact with indirectly exposed surfaces as well as providing disinfection of the air in the area being treated.

Residue eradicated​

Middleton said that an added benefit of using ozone in the food and drink processing sector is that it is environmentally friendly, with any residual ozone decomposing to oxygen. In terms of vapourised hydrogen peroxide, she added, it is also rapidly broken down to water vapour and oxygen, and thus leaves no problematic residues.

She said that these whole room disinfection techniques can be used daily or part of the periodic cleaning and disinfection procedures that occur monthly – it depends on the output of the processor involved or the level of decontamination required.

She said the methods might also only be employed when decontaminating an area after a pathogen contamination incident.

Usage within food industry ​

Mark Fielding, director of the Radical division of Steritrox told this publication that food manufacturers have been steadily registering interest in its ozone disinfection technique and the company has sold either the mounted version or mobile units of its equipment to around a dozen processors, mainly cooked meats and fresh food manufacturers, in the past 12 months.

He said that take up though has primarily been from food processors that do not operate on a 24 hour basis so the sanitization with its gas-based system takes places overnight.

However, he said the company can provide high volume processors requiring continual line operation with a system that allows the factory to return to full production within an hour.

Regulatory compliance​

Another advantage to using these techniques is that the decontamination process can be certified.

Bioquell, a supplier of vapourised hydrogen peroxide, said it is able to provide detailed microbiological efficacy documents as well as expertise to assist with the eradication of a particular pathogen and show a food processor to be regulation compliant.

“The provision of microbiologically safe food is paramount to meet the needs of the food manufacturer’s regulators including Environmental Health and the Food Standards Agency, as well as the supermarkets themselves who regularly audit suppliers, and food law,”​ states the supplier.

Middleton said that detailed data about the outcome of the three year research project will be published at the end of this month but will only be released to the Campden BRI membership. The team's next focus, she said, will be on the attachment of salmonella in dry processing areas.

Supplier snapshot​

Other suppliers of vapourised hydrogen peroxide include Minntech based in the Netherlands, and UK based Validated Hygiene Solutions and Steris Ltd. Yorkshire based JLA and Dryden Aqua, located in Scotland, also supply ozone technologies for whole room disinfection.

The third part of our special edition on decontamination will look at current factors influencing the design of new hygienic food processing equipment. ​​