When processing foods on an industrial scale, a constant heat source is required to produce a consistent product. In the food processing sector, ‘heat transfer fluids’ (HTFs) are used (e.g., Globaltherm® FG) as they are efficient in the transfer of heat from one location to another.

A recent article published in Applied Thermal Engineering entitled ‘Food processing: The use of non-fouling food grade heat transfer fluids (HTF)’ [1] discussed the importance of using HTFs that are certified ‘food grade.’ This effectively means that they can be safely used in food processing if they carry a ‘HT-1’ certificate from an approved body such as the NSF food safety division in the USA, which is a globally recognised standard. However, this is not the only feature of a food grade HTF. They are generally colourless, non-toxic and non-irritating, and they are non-fouling and form less carbon during degradation. These features are desirable for the safe operation of a production plant as this means that the carbon residue that is formed is smaller and less precipitation is formed on the internal surfaces of the plant pipework [2]. 

Figure 1. An image of everyday foods produced using heat. (Copyright: agrofruti / Shutterstock)

A food grade HTF is therefore at the heart of food processing but also consumer safety (see Figure 2). The aim of this article is to discuss the safe manufacture of foods in relation to food and drink. The perspective of the consumer, the seller, the manufacturer and the producer are discussed separately in this article.

Figure 2. Food grade heat transfer fluid and its role in relation to consumers, sellers, manufacturers and primary producers.


Consumers do not expect any HTFs to be present in their food and drink products. It could be considered that really the highest expectation of a food and drink product's safety, quality and integrity sits with the consumer in terms of trust, whether they would initially purchase it, how it meets their expectations and continues to delight through to repeat purchase and recommendations to friends and family (see Figure 3).

Figure 3. Hierarchy of expectations for food safety and quality through the food supply chain.

With 92% of people in the UK saying that they shop in a supermarket, and with supermarkets dominating the market at 85% for the sale of many of the UK food and drink products, trust in the standards of the goods that they sell has to be extremely high. All the top 10 supermarkets in the UK have developed their own standards of supplier assurance and food safety codes of practice, many of which are seen as the gold standards for manufacturers across the world. These standards may even specify the type, makeup and manufacturer of an approved HTF that can be used. After Switzerland, the UK is the largest user of own or private labelling of food and drink products within the supermarkets. The retailer's brand reputation is even more at stake with their name on the product that may sit in the consumer's store cupboard or refrigerator (see Figure 3).
All manufacturers supplying retailers, wholesalers and the public sector with food and drink will have consortia agreed auditable standards to achieve. Invariably there will be clauses within these standards about protection of the product from any chemical, physical biological or allergenic material that may be objectionable, harmful and unwanted. Many manufacturers will choose internationally recognised standards such as ISO22000 or HACCP to manage their food safety or even adopt the quality practices derived from the car manufacturing sector such as six sigma and total quality management in order to drive their continuous improvement, thereby reducing the chance of contamination of product or process with a HTF. These will invariably detail specific testing, cleaning and prevention requirements within them (see Figure 3).
Private quality assurance marks and standards are often used within food manufacturing to add value to products or assure trust and traceability within the supply chain. The British Retail Consortium (BRC), in its 7th version currently, is a good example of one that will include clauses to prevent the contamination of product by a HTF, but may not specify a particular HTF other than those designated as food safe. Slightly less onerous standards exist, such as Safe and Local Supplier Approval (SALSA) or Safer Food, Better Business (SFBB) for many smaller businesses wishing to enter new retail, wholesale, food service and public sector markets. Although not mentioned specifically, HTFs may be considered as chemical contaminants and therefore the requirements for control are implied (see Figure 2).
As well as a very small number of powerful retailers in the UK driving improving food safety standards, the insurance market has its part to play in pushing standards forward. Many organisations develop greater controls of HTF by the need to mitigate risk and therefore reduce premium costs and levels of excess. Most stakeholders in the supply and production of food and drink will find that their insurers will take a keen interest in their control and use of HTFs (see Figure 3).
It could be considered that legislation offers the lowest level of standard with regards to protection of public health in this supply chain. It must be done as none of the other higher standards can be achieved if legal standards cannot be met. However interpretive guides, codes of practice, good agricultural practice good manufacturing practice, good hygienic design and practice all inform and are informed by statute. EC852/2004 requires all involved in this supply chain with exception of the customer and the farmer to use a risk based HACCP approach to controlling food safety (see Figure 3).
The use of a food grade HTF in the processing of foods is critical to the safety of consumers. HTFs are also central to all activities in the production and supply of foods and drinks. This article also explored the perspective of the seller, manufacturer and producer. In terms of sellers, standards of supplier assurance and food safety codes of practice specify the type, makeup and manufacturer of an approved HTF that can be used. For manufacturers, continuous improvement is critical for reducing the chance of contamination of foods and drinks with a HTF. Such processes will detail specific testing, cleaning and prevention requirements that a manufacturer needs to operate to and are audited against. For the producers too, the drive to mitigate risk is rewarded with a reduction of insurance premiums and this is where insurers will define the type of HTF to be used, how frequently it should be analysed as well how often staff should be trained. •

Please contact the author for reference materials cited in this article.

The author would like to acknowledge the writing support provided by Red Pharm communications, which is part of the Red Pharm company (please see @RedPharmCo on Twitter).