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When quality really counts

28 September 2020

Are you using the right quality of steam in your food and beverage processes? Suzanne Gill reports. 

Steam is utilised widely throughout food and beverage production facilities, thanks to its ability to offer an energy efficient, reliable and flexible way to transfer heat for use in many applications. 

Because it is routinely used in direct contact with food products, in addition to its role in sterilising production line equipment, steam should be considered as an ingredient. As such it is vital to ensure that the right quality and purity of steam is employed, to avoid any potential risk of product contamination. 

Francisco Pedrosa, business development manager EMEA for Spirax Sarco, is a clean steam specialist who spends much of his time educating and training customers in the correct use of clean steam. He is often surprised that many users of steam in the food processing sector misunderstand what ‘clean steam’ actually is.

Despite the fact that ordinary process steam is sterile, it does still contains contaminants – including a variety and inconsistency of boiler chemicals. “Even though boiler chemicals should be FDA approved when used in food grade applications, there remains a further requirement not to exceed stipulated maximum quantities of these chemicals. However, when you are injecting steam directly into a food product there really is no way of monitoring what quantities of chemicals are in the steam at any point in time at the point-of-use.” 

Giving adequate consideration
Pedrosa believes that too often, food safety is not given adequate consideration when it comes to the use of steam and he argues the importance of its inclusion within an operations Hazard Analysis and Critical Control Point (HACCP) principles. “Steam can potentially carry contaminates that can find their way into the food product so it is important to apply HACCP to ensure steam is properly analysed if it is injected into the process,” he said. 

Another often encountered clean steam misunderstanding relates to the use of filters. “A filter will not make steam ‘clean’ it will just remove particulates,” explained Pedrosa. “The only way to generate truly clean steam and to completely eliminate the risk of contamination is to add a secondary clean steam generator to the existing steam production system. The water used within the secondary process must first go through a Reverse osmosis (RO) process which ensures that all chemicals and other possible contaminants are removed from the water. The use of RO water ensures that no chemicals are introduced back into the clean steam generator so there will be no contamination of product by the steam.”

Clean steam also needs to be used for sterilisation of equipment that comes into direct contact with food. “While the high temperature of steam will adequately kill any bacteria, the quality of clean steam needs to be considered to prevent  contaminate-containing residues on the equipment which could be passed on to food products.”

Culinary steam, or filtered steam is often considered to be a clean steam, and it is important to note that this is not the case. “FDA standards highlight the fact that steam used in direct contact with food has a bare minimum requirement of the inclusion of a 5 micron filter as close as possible to the point of use and thereafter in stainless steel. However, as I have already explained, contaminants can still be carried through a 5 micron filter. So, in effect, culinary steam can still result in contamination of food,” said Pedrosa.

Explaining more about the additional requirements needed to produce clean steam Pedrosa explained that clean steam systems are, in effect independent generators, sized to meet the quantity of clean steam required. 

While the addition of a clean steam system will significantly add to higher quality standards in comparison with a standard steam system, Pedrosa points out that it is health and safety that should be front of mind when specifying a clean steam solution. “HACCP demands the elimination of risk associated with a process and the only way to achieve this is to use clean steam. While it is possible to ‘minimise’ the risk by putting filters in place but this will never ‘eliminate’ risk.” 

A vital element of the clean steam process is to create RO water using a treatment process which sees it move through a system of reverse osmosis membranes and then going through a water softening process and finally through a carbon filter before it enters the clean steam generator. Up to 20% of the original water will be eliminated as waste because it contains contaminants. It is important that all equipment from the point of generation of clean steam to the point of use is stainless steel.

Ideally steam should be as close to saturation point, as the dryer the steam greater the heat transfer characteristics. A clean steam generator will provide a consistent standard of dryness in terms of both product quality and meeting compliance standards. 

Regulation EC 1935/2004 
In conclusion, Pedrosa made one final point – because steam often comes into direct contact with food, the equipment used to generate clean steam must also meet the requirements of Regulation EU 1935/2004 (more commonly known as the Framework Regulation), which states that materials put into contact with food ‘must not transfer their constituents to that food in quantities which could endanger human health, or bring about an unacceptable change in the composition of the food, or cause a deterioration in its organoleptic characteristics’.

Steam generators and systems which supply steam for direct contact with food and beverage product should comply with this regulation – and Pedrosa confirmed that clean steam solutions from Spirax Sarco are certified to meet EC 1935/2004, so users can be confident that all the materials used in their steam clean system will not impart any odour or chemical which might contaminate a product. 

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