Focus on factory cleaning: On spray watch 

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Focus on factory cleaning: On spray watch 

Industry hygiene processes have evolved with technological progress, as Michelle Knott reports

It's not every day someone finds a dead mouse in their sliced loaf, but 2010 saw the usual parade of contamination-related product recalls that could have led to a host of less visible but no less unwelcome surprises turning up in food products. Chicken roll and black pudding carrying Listeria, Salmonella in coriander, mouldy lemon and lime drinks and spring water playing host to E.coli hardly appetising prospects. With reputations at stake, hygiene is always high on the food industry's agenda and there's constant pressure to improve.

"Changing hygiene practices don't tend to get driven by legislation because that tends to be very general, with a basic requirement to produce clean, safe food," says Mike Law, chief certification officer for certification organisation Cert ID Europe. "It's much more to do with customers."

The standard that the majority of retailers and foodservice customers in the UK demand from their suppliers is the British Retail Consortium (BRC) Global Standard. "One or two supermarkets work with their own schemes but others won't even talk to potential suppliers without it, so in some instances it could be regarded as a licence to trade. The growing emphasis on local sourcing also means that smaller suppliers are increasingly falling into the net," says Law.

The current standard aims to set out hygiene objectives without being too rigid about exactly how users should achieve them. But BRC is currently consulting over the next, sixth, edition of the standard and this may change the picture when it comes into force at the start of 2012.

Prescriptive standards?

Some feel that modern hygiene standards are already very prescriptive and that this may be an opportunity to redress the balance. "You can tighten up the cleaning and disinfection regime to the point where it doesn't work because you have a factory that doesn't work," says Stuart MacNeil, sales manager for CCL Pentasol, which supplies industrial cleaning and disinfection chemicals and supporting services. "We mustn't drive ourselves down a cul-de-sac."

MacNeil adds that modern business realities are also driving changes in cleaning practices: "Years ago factories had the luxury of spending 12 hours on production and 12 hours on cleaning. Now it's 22 hours of production and two hours of cleaning in a shift pattern that rotates between different areas of the factory. It makes things much more complicated."

"It's difficult to say what the changes may be in the sixth edition, but it's fair to say that everything is on the table," says Law. "There's been a lot of development work on systems-based approaches [such as hazard analysis critical control points (HACCP)] but retailers are interested in practical aspects 'at the coal face'. They want auditors who are out in the factory looking at the actual manufacturing processes, not sitting in an office looking at manuals. How that will manifest itself is very open to debate at this stage."

It's not only the BRC Global Standard that could reflect this change of emphasis. "There is a general movement, not necessarily away from HACCP, but towards placing more emphasis on the prerequisites of good hygiene with good factory design and infrastructure," says John Holah, head of food hygiene at Campden BRI.

Whatever happens with the BRC, other standards are already driving this trend, namely ISO 22000 and its companion standard PAS 220:2008. Publicly Available Specification (PAS) 220:2008 lays out detailed requirements for hygiene prerequisites, from building construction and layout to pest control and personnel hygiene.

"Some aspects, such as waste management and pest control, are important but they're not major sources of contamination," says Holah. "Proper segregation and controlling the flow and behaviour of people are the most important things. I think we'll see changes in sectors such as dry goods, where they'll be learning lessons from high-risk chilled food manufacturers."

The continuing evolution of hygiene practices and standards is being accompanied by technological progress. In this case, Holah says that two technologies have arrived on the scene in the past five years that have potential to make a big impact in British factories.

One is whole-room disinfection and the other is antimicrobial surfaces.

Whole-room Disinfection

Whole-room disinfection floods the entire space with powerful oxidisers such as ozone or hydrogen peroxide vapour. Research completed by Campden BRI in 2010 found that conventional chemical fogging reduced airborne microbial populations and the numbers of attached microorganisms on horizontal surfaces but had minimal effect on the numbers on vertical surfaces and beneath equipment. In contrast, ozone and hydrogen peroxide penetrated every surface and succeeded in tackling microbes throughout the treated area.

"At the moment we may clean the high walls and overheads of a factory once a month. That's enough for 99.99% of the time but it doesn't sterilise the environment and eliminate bugs from the space. Over time each factory will develop its own microflora and that may include Listeria, Salmonella or other pathogens," says Holah.

Factories could tackle these persistent organisms using whole-room disinfection every few weeks or months using a high concentration of the active agent. Alternatively, ozone or hydrogen peroxide sterilisation might be incorporated at a lower concentration into an everyday cleaning regime, enabling the factory to eliminate a stage of chemical disinfection. "There are factories that have undertaken this approach and are successfully controlling food contact surfaces. There's also some evidence that they may be controlling the environment a bit better too," he says. "There's a lot of interest in the research because there are very few real advances in hygiene."

Advantages of whole-room disinfection include savings in the costs of chemicals and water and the absence of any chemical residue, since ozone and hydrogen peroxide decompose relatively rapidly into oxygen and water. The main downside is that the procedure can only be carried out in an isolated space that's been cleared of personnel. However, some commercial systems have managed to shrink this window of downtime to a manageable size. For example, Steritrox, which makes systems based on ozone, claims that its technology typically makes it safe to re-enter the room within an hour.

"The latest developments in whole-room disinfection are all about making it easier to use," says Neil Brown, technical director of Hygiene Group, which provides cleaning services across a range of industries. "Finer atomisation and the ability to quench the room faster are both good examples."

As a potential end user, he believes ozone is more interesting than hydrogen peroxide because it's easier to handle and won't raise the same corrosion issues. Although Hygiene Group doesn't currently carry out this type of whole-room disinfection in the food industry in the UK, Brown says that more localised use of ozone also has great potential to speed up cleaning cycles: "We're looking particularly at the use of ozone in vegetable handling and fruit preparation, where it is ideal because it leaves no residue."

On the other hand, Brown stresses that the "right" cleaning system depends on the application. In some cases, a cleaning residue can be a bonus because it provides ongoing protection that prevents organisms from re-establishing themselves. "The residue from our Biomist system can be left in place to provide protection, for example, over the weekend," he claims.

The technology behind Biomist lies somewhere between whole-room disinfection and conventional terminal disinfection. It uses carbon dioxide to blast a fine aerosol including alcohol and quaternary ammonium compounds at the treated area. "It can penetrate complex machines and rough surfaces. Even the blind side gets treated," says Brown.

Anti-microbial surfaces

While the Campden BRI research confirms that whole-room disinfection is effective, Holah believes there's still work to be done to establish just how useful anti-microbial surfaces are going to be in the hygiene armoury. Anti-microbial surfaces are impregnated with a biocide that is released gradually by a process of diffusion to provide continuous protection at least that's the theory. Although these materials are already being widely marketed, Holah thinks there are still questions that need to be answered.

"There are certain controlling actions we can take when it comes to microbes. The important parameters are temperature, moisture, nutrients, oxygen and time," says Holah.

"We can't control the presence of nutrients or we wouldn't have a food factory. We can't control temperature at above 100°C or below freezing or we couldn't have people in the factory. It's the same thing with oxygen. And we can't clean every two minutes or we wouldn't have a production process, so the only control we have left in a production environment is to keep surfaces dry."

The question that remains then is whether an antimicrobial surface is wet for long enough to enable the biocide to diffuse and become active. "If it's kept wet for 20 minutes during the cleaning cycle, is that enough for the biocide to diffuse and do its job? The research still needs to be done," says Holah.


British Retail Consortium - 0207 854 8900

Campden BRI - 01386 842 000

CCL Pentasol -01942 722 000

Cert ID -01675 475 607

Hygiene Group - 0800 731 4893

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