Thermal fluids pose contamination risk

By Rick Pendrous

- Last updated on GMT

Non-food-grade thermal fluids can present contamination problems
Non-food-grade thermal fluids can present contamination problems

Related tags: Heat, Temperature

Many food processors will be surprised to learn that contamination of products can result from the use of thermal fluids that are not of food-grade quality, should it come into contact with the food.

Because of this risk, companies should invest in high-quality food grade thermal fluids within their processes, Clive Jones, md of thermal fluid expert Global Heat Transfer, has claimed.

Unlike many other sources of contamination, such as contaminated wash water or pathogens from contaminated ingredients and cross-contamination when equipment isn’t cleaned down properly, heat transfer fluid can prove to be a “hidden contaminator”, ​Jones warned.

Heat transfer fluid can foul food products if it comes into contact with it, for example if the system has a leak, said Jones. “The best way to prevent contamination in this situation is to opt for a food-grade thermal fluid,”​ he added.

‘Prevent contamination’

Food-grade thermal fluids carry a HT-1 certificate, granted by the US Food and Drug Administration (FDA) or the NSF International, if they have been approved for use in food and drink processing, explained Jones.

“They are typically described as colourless, non-toxic, non-irritating and non-fouling,”​ he said. “As thermal fluids are chemical agents, there is potential that they could come into contact with food and consumers. Although it may seem like a small risk, it is not an unusual occurrence.”

Jones cited the example back in 2000, when 39,090kg of sliced and packaged turkey had to be recalled after consumers complained the product was off-odour, off-flavour and caused temporary intestinal discomfort after consumption.

“Testing proved that the product had been contaminated with non-food grade thermal fluid,” said Jones. “To ensure consumer safety isn’t compromised, food and drink manufacturers should always use thermal fluid suitable for incidental contact with products.”

‘Common myth’

Jones rejected as a “common myth”​ the belief that food grade thermal fluids cannot operate at the same high temperatures as standard products. He said specialist fluids were available that can operate from -20°C up to 326°C, thanks to their outstanding thermal oxidation stability.

“Food grade thermal fluids are also known to have a lower ‘total acid value’ than non-food grade,”​ he added. “This means that, as well as being certified for incidental contact with food products, using food grade thermal fluid will lead to lower fouling and corrosion on internal structures during thermal degradation.”

Global Heat Transfer offers a maintenance package called Thermocare, which includes 24/7 on-site engineering assistance, regular sample analysis, condition monitoring of heat transfer fluid, system health checks and training for a range of personnel including engineers, line workers and health and safety staff.

Related topics: Meat & poultry, Manufacturing

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