Muddied waters: When a clean plate is simply not enough


The warewashing industry’s whole modus operandi is transforming dirty plates, glasses and cutlery into clean, sparkling versions of their selves, ready for service again.

But one of the more delicate debates within the market involves determining the difference between an item that is ‘clean’ and one that is hygienically sanitised.

A quick look at various food safety guidelines published by different bodies from around the world reveals that high temperature warewashing typically refers to wash water temperatures of between 66°C and 74°C, and final rinse temperatures of at least 71°C. But aside from sectors such as airline catering, warewashing sanitisation has largely been a matter of self-regulation.

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Earlier this year, things came to a head when warewashing equipment manufacturers met with the Food Standards Agency (FSA) to discuss concerns that operators were being told by environmental health officers that their dishwashers did not comply with new guidelines to eradicate E. coli 0157. Although those guidelines were subsequently revised, experts believe the long-term solution lies with the creation of UK standard that brings clarity and consistency to the topic.

That is expected to happen at some point in the future, although it is impossible to say when. However, developments in Europe certainly threaten to add urgency to the debate.

Meiko, for instance, recently confirmed that its manufacturing facility in Germany had received notice from DIN, the respected German Institute for Standardisation — which helps to set ISO standards — that a new standard (DIN SPEC 10534) will be introduced requiring that caterers ‘test’ for the hygienic operation of their commercial dishwashers.

Although the new DIN standard is not in practice yet, it is likely to be introduced over the next few years and would effectively require caterers to prove and record that all items washed in dishwashers had reached the minimum temperature and time to kill bugs such as E. coli 0157.

The creation of a common sanitisation standard is something that most manufacturers would welcome with open arms.

Bob Wood, sales director at DC Products, is on the side of those who insist it is much needed. “For too long the British industry has been shrouded in hearsay and assertions from different avenues claiming to be the UK standard, when in reality there just simply hasn’t been one,” he remarks. “Because of this, manufacturer specifications and base standards have been open to variation and FBOs potentially left to extricate a web of information to develop their own best practice of pre-wash, handling and post-wash management without any recognised British Standard to refer to.”

Any future UK standard would most likely adopt some aspects of the German DIN standard, according to manufacturers involved in preliminary talks regarding regulation. This recommends a 60°C to 65°C wash tank and 80°C to 85°C rinse cycle in order to achieve a 5 log reduction in micro-organisms, and would then need to be combined with some form of testing validation and general best practice.

“Although certain critical temperatures are already being mooted by the industry, it’s our understanding that the temperature has not been decided upon and in addition the temperature validation method is still to be finalised after data from trials on the accuracy and reliability of thermal strips is analysed,” says Wood.

As it stands, thermal label testing is perhaps one of the best known techniques for measuring temperature, providing catering management or personnel with a visual assurance that a sanitising contact temperature has been achieved on the surface of the products being processed.

Meiko UK says it is already offering thermo labelling as a feature on all of its front loading and pass through utensil washers and on all rack transport and flight machines, but with increased electrical load.

“Every Meiko warewashing machine constructed for thermo label testing offers a consistent final rinse temperature at the boiler of minimum 82°C and a surface contact temperature of 71°C guaranteed on washed product, which for kitchens that handle mixed food products and fresh meat produce side by side provides a very high level of hygiene security,” says UK managing director Bill Downie.

There is already a track record of thermal label usage in North America and this would surely bode well if it ever became compulsory in the UK, suggests Tim Bender, sales director of warewashing UK at Hobart. “Thermal label testing has been mandatory in the US for many years and is part of everyday life. There is no reason to believe that it could not be adopted as easily over here and, in fact, would probably be welcomed by operators because it would allow them to check for themselves that their equipment is performing correctly.”

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Stuart Flint, training and business development manager at Electrolux Professional, says that thermal label testing has been a requirement on many manufacturing sites for some time, but it would “wholeheartedly welcome” hygiene testing given that there is currently no UK standard for manufacturers to test against. “We have used the American NSF standard which has been around for the longest time and is the most stringent and quantifiable test around,” says Flint.

Wexiodisk was one of the manufacturers involved in initial discussions with the FSA over regulatory updates. Having been aware of the potential for changes, UK and Ireland country manager, Simon Frost, says the company has taken the initiative to develop what it calls a ‘Web Service Tool’ which can be installed on all its key appliances.

This essentially provides a way for operators to monitor water temperature, wash tank temperature and rinse tank temperature. “Operators are able to wirelessly monitor the effectiveness of their appliance, broken down by individual wash cycle, while a fully downloadable HACCP reporting function will satisfy the requirements of the Environmental Health Officer and the FSA,” explains Frost.

Should thermo labelling ever become a mainstream requirement on industry-standard frontloading and passthrough machines, it has been suggested that it could command some improvisation from OEMs. Additional heating would be required within the wash tank and with the drive to reduce water consumption, speed up cycle times and reduce water volume unlikely to abate, a new type of construction may be required.

More than one manufacturer stressed that achieving the sort of temperatures seen in airline catering would require machines to use more energy and possibly more water.

Generally speaking, though, the consensus is that the market’s more established branded manufacturers would be well-placed to adopt any legislation governing warewash hygiene should the day ever arrive.

“Most quality manufacturers will already manufacture machines that can reach these sanitising temperatures, and will, to some degree or another, produce machines whose temperatures can be adjusted to reach these temperatures,” agrees Paul Crowley, marketing manager at Winterhalter. 

“For some years, certain hospitals have demanded warewashers that produce thermal disinfection temperatures. It is only the top manufacturers that have been able to satisfy this demand. Winterhalter is also in a fortunate position that it can offer thermo-chemical disinfection, which is cheaper for customers and kinder on the environment. The leading manufacturers are ready to face any standards that may ensue but we would certainly question if the second and third tier manufacturers are ready in the immediate future.”

Glen Crossland, marketing manager at Dawson, which markets the Comenda brand, adds: “I believe any issues arising from this testing will surface for the brands supplying equipment at rock bottom prices who compromise machine quality and performance for price. Generally speaking, I believe standards are high in the UK warewashing market and this will or should only affect a small number of manufacturers in the first instance.”

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While the issue of warewash sanitisation has brought thermal label testing to the fore, there are some who remain unconvinced by its effectiveness, such as Julian Lambert, sales director at Maidaid. “If general hygiene testing standards are introduced, then the impact will be very positive on the industry as it will ensure accountability is put in place,” he says.

“However, thermo label testing is not an accurate way of testing the dishwasher, as the surface area inside is so large that the label cannot measure the temperature of the entire machine.”

He suggests that testing with an ATP monitoring kit, which allows users to take samples of all aspects of the machine, from the dishes to the walls inside, provides a much more accurate result. Lambert also contests the view that in order to achieve hygienic results, high temperatures are required.

“The German Institute of Standardization is working on a standard that will require caterers to test the hygienic operation of dishwashers; this does not specify the use of thermo labelling. Indeed, our sister company Crystaltech has recently carried out tests that prove that using a low temperature wash, combined with certain chemicals such as ‘Maidaid Low-Temp’ will achieve the same hygienic results and a better visual finish.” (See panel on ‘high temperature washing’ above).

Should thermal label testing prevail as the de facto vehicle for hygienic testing, suppliers concur that a level of uniformity would have to be established from the outset. As Electrolux’s Flint notes: “The main issue with thermo label testing is that there is no standard for the label itself. Some labels react quicker than others, and so with washing and rinsing times being reduced the labels that react slowly are indicating that the dishwasher is failing when in reality it is not.”

Wood at DC Products agrees. He claims DC’s own tests have revealed discrepancies between varying label manufacturers and the time of exposure to varying temperatures required to activate the label.

“[Regulators] will also need to identify the surface that the label is adhered to inside the machine — obviously steel responds very differently to plastic ware or crockery — to ensure that all tests are being carried out to an equal and exacting standard,” he says. Whatever your stance, Bender at Hobart points out that the process of defining a standard has yet to be started, so any talk of what it might be or whether thermal labels will be used for validation are very premature. “It may well be a couple of years before a standard is defined and agreed,” he says.

Distributors and operators can only watch and wait to see how events unfold. But in the meantime that won’t deter manufacturers from developing their own solutions in a bid to provide evidence of sanitisation in the absence of any over-arching legislation.

Work on UK sanitisation guidance underway

The market’s premier catering equipment manufacturing body, CESA, says it recognises that thermal label testing and sanitisation is an “important and complex” issue for warewashing manufacturers.

Current chair, Nick Oryino, says the association’s position on the situation is clear: it is is keen to encourage a full debate and engage with members to get their views, understand what such a standard would mean to them and allay any anxieties.

“Effective sanitisation is dependent on many different factors — temperature, pressure, detergents, water quality and their interactions together. Currently warewashing manufacturers balance these to achieve the best possible wash and effective sanitisation. Any implementation of new standards will require careful consideration of all these by the manufacturers. It is also the case that different sites will have differing specification requirements to suit their needs.

“There is work being undertaken in the UK by the Food Standards Agency to look at the development of a guidance document on the control of cross-contamination of E. coli 0157 by heat disinfection. At European level the work has started to develop a standard for the effectiveness of dishwashing equipment based on German DIN SPEC 10534 standard.

“CESA is well-positioned to represent the industry and will be representing the views of manufacturers to assist in the effective development of any legislation or guidance. This work will also need to be considered in relation to the Ecodesign directive and the measures that it will require as and when the work commences.”

High temp washing a ‘misconception’

A commonly held view on the issue of hygienic warewashing is that the only way to guarantee sanitisation in dishwashers is to wash and rinse at temperatures between 66°C and 74°C.

But Derek Maher, managing director of warewashing installation and repair firm Crystaltech Services, calls this a “misconception”, arguing that if you were to follow that methodology through to its natural conclusion then we would all have to wash our hands in boiling water, rather than using a cleaning agent at a lower temperature to achieve the same level of disinfection.

He argues that bodies such as the FSA, DIN and the US Food & Drug Administration (US FDA) are all trying to achieve a measurable and sustainable method of disinfection, not sanitisation, and that both DIN and US FDA documentation states that warewashing machines can be operated at lower temperatures if the required level of hygiene is achieved.

Maher claims his biggest challenge has been finding a method to demonstrate the reliability of using a low temperature technique without having to send swab samples away for costly and lengthy bacteria analysis, but says this has now been achieved through the use of 3M’s Rapid Hygiene Monitoring System, which employs ATP (adenosine tri-phosphate) Bioluminescence.

“While specific detection requires samples to be laboratory tested, the ATP Clean-Trace device gives a general indication within 30 seconds,” he explains. “This device, which is in common use by EHOs, means we are now the first company in a position to fully support our customers in reducing operating costs and proving disinfection. We have carried out a number of successful trials with high-profile customers and we are preparing the case studies for release shortly.”

Maher says he has been working with chemicals supplied by sister company Maidaid to carry out rigorous tests in laboratories and on site for the past 15 years in a bid to prove that by using alternative chemicals, commercial kitchens and bars can get the level of cleanliness they need at lower temperatures.

“It’s a no brainer, as this low temperature process also prolongs the life of glassware and crockery,” he says. “I know the industry feels it has a solution with the implementation of heat recovery units, but why try to reclaim energy, with a more costly machine, when it can be saved in the first place?”

Tags : catering equipmentManufacturerstemperaturesthermo labellingwarewashersWarewashing
Andrew Seymour

The author Andrew Seymour

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