After hygiene, precise temperature control is of vital importance for the food and beverage industries; both in terms of regulating the working environment as well as specific production processes – to ensure consistent quality throughout the year. However, many manufacturers are mistakenly overlooking one element of their cooling systems which could pose a serious contamination risk when disaster strikes.
Here, Brent Hall, Technical Manager at ICS Cool Energy, explores what manufacturers need to know about glycol and how they can ensure their cooling system is performing at its best and safely.
Setting the scene
Glycol is a staple in all chiller-based cooling systems operating below 6°C, and is effectively an anti-freeze solution with built-in inhibitors to prevent the heat transfer fluid from damaging chiller systems. This usually occurs from freezing, especially if the chiller is outside, or from the corrosion of internal parts.
Used throughout industry in secondary refrigeration systems, glycol can be separated into two main categories: mono-ethylene glycol (MEG) and mono propylene glycol. Most food processing plants are well aware of the high toxicity levels of MEG and it is therefore rightly overlooked in favour of MPG for all food-related applications.
An MPG offers low oral toxicity levels and for the last 20-30 years, it’s been perceived as the safe solution where there is a risk of incidental contact with food. In fact, MPG as a compound is actually used in some food colourings and flavourings, as well as e-cigarettes.
However, MPG is fundamentally very corrosive. While it represents minimal risk to humans, an MPG, even when diluted with water, can prove to be highly corrosive when it meets metallic elements found within a chiller system, namely those made from aluminium, copper and steel. Therefore, the vast majority of suppliers recommend the use of inhibitors to counteract the corrosive nature of the glycol, and this is commonly accepted within the food and beverage processing sector.
5 tips for getting the most out of your glycol
1. Only use inhibited glycol
Uninhibited glycol and water mixtures are very corrosive, often even more than plain mains water.
2. Don’t mix glycols
Different types and brands of glycol shouldn’t be mixed. Most modern glycols contain inhibitors and are dyed for identification. If accidentally mixed, incompatibilities can lead to separation and/or reaction, resulting in gel formation which will clog filters, strainers, and pump suctions.
3. Checking your local environmental rules
Some areas have regulations regarding the use and disposal of particular glycols and antifreeze solutions, concerning things such as ground structure, the water table and drainage. Be sure to consult your local authority to check the local environmental rules. Bio- glycols are an environmentally-friendly alternative.
4. Use the correct water
Most systems use ordinary mains “tap” water. However, applying the appropriate inhibitors and biocide is of vital importance to prevent chiller system damage. Using one of the “Pure” waters – distilled, demineralised, de-ionised or RO Water – will remove all the unpredictability associated with town mains water. We recommend the use of pure water – distilled, demineralised, de-ionised or RO water – with a suitable (minimum 20%) inhibited glycol mix to give the ultimate system protection.
5. Maintain your chiller and system’s hygiene and fluid
If either of the water/glycol solution or system pipework are deficient in any way, the chiller’s operation will be compromised and the heat transfer capability will be reduced. Filters/strainers should be installed and checked regularly, although the best policy is to tackle the source of any contamination. The chilled water system must be flushed, cleaned and sanitised prior to adding a new water/glycol solution. It must also be regularly sampled and tested to ensure there are no underlying or progressive contamination and/or corrosion issues.
The hidden toxins – crucial facts
However, while these inhibitors are necessary to ensure the chiller system is able to operate efficiently and effectively, what’s often missed is that a lot of these commonly-used inhibitors do not offer the same levels of low toxicity as MPG.
Crucially, the glycol inhibitor toxicity information is frequently not reflected in the safety data sheets due to the relatively low volumes used, so they too are missed by the end-user.
An uninhibited MPG and water solution would not pose a risk of poisoning if a leak were to occur and it came into contact with a product intended for human consumption. The same cannot be said, however, if the heat transfer fluid has been treated with the majority of anti- corrosion inhibitors available on the market.
Ultimately, using the wrong inhibitors means the MPG solution creates a serious risk of contamination. Vitally, this fact is not known by many in the food industries.
Solving the problem
How can the food processing industry therefore start to tackle this potential contamination risk?
Awareness is the first step. I urge all food and beverage manufacturers to check with their current glycol supplier whether the substance poses a contamination risk if it were to come into incidental contact with food.
Next, consult with industry bodies. There are a number of organisations which can offer guidance on ‘food safe’ products, with the NSF being a key authority. The NSF can provide a list of products which are accredited as safe to use in food processing applications, and can therefore provide a reliable alternative to MPGs with potentially toxic inhibitors.
These products, which include the NSF-accredited FlowCool-FS glycol from ICS Cool Energy, feature organic inhibitors which can guarantee the required levels of corrosion prevention and thermal efficiency, without posing a risk to human health if inadvertently consumed. These organic inhibitors have been developed by a team of skilled chemists which, when combined with an MPG, will offer end-users the desired peace of mind when it comes to avoiding potentially poisonous contamination.
Ultimately, the food processing industry is a rightly risk-averse market sector. One small leak can cost a company its credibility and share of the market, and it is becoming increasingly hard to recover reputational damage in such a fast-paced and competitive market.
Glycol is an ever-present fixture in most cooling systems in food and beverage processing plants across the country. However, many manufacturers may unwittingly be exposing themselves to serious contamination risks if a leak were to occur and the glycol used was treated with potentially harmful inhibitors.
Fortunately, new products are entering the market which combine MPGs with organic inhibitors to deliver a heat transfer solution which is both reliable and, crucially, one hundred% safe for incidental human consumption if a leak were to occur. In an industry where there is no room for error, you can’t underestimatee the importance of extra peace of mind.