Busting the myths about food pasteurisation

09 December, 2016

Pasteurisation has been established as a key method of destroying pathogenic bacteria in the food and drink industry since its invention in the middle of the nineteenth century, although the origins of heating wine for preservation go back to China in the 1100s. However, as food and drink processing becomes more complex and food chains longer, the importance of pasteurisation has increased.

At the same time, the technology has also improved, with developments in the equipment used for both HTST and LTLT* methods. While simple plate heat exchangers may still be suitable for the pasteurisation of simple fluids such as milk and fruit juices, more textured and viscous products, such as cooking sauces, creams and curds will require different solutions in order to maintain their quality and texture. Here, we expel some popular myths about food pasteurisation:

Myth 1: Pasteurisation is expensive

While the exact costs will vary with each installation, there is no doubt that there is a capital cost to pasteurisation. However, compared with the potential losses due to food spoilage, or worse a food safety incident, these costs are insignificant. In the US, the costs of recalling food products have been shown to average US$10 million**, before accounting for brand damage. Closer to home in 2012 there were 80 food related product recalls*** in the UK and the Food Standards Agency estimates that Listeriosis cost the UK economy £245 million a year****. Against these potential costs, the capital cost of a corrugated tube heat exchanger based pasteurisation system is a sound investment. Alongside the capital costs, the running costs of a pasteurisation unit need to be considered.

Myth 2: Pasteurisation is too complex

Pasteurisation itself is a relatively simple process. It requires that a material is held for a certain time at a certain temperature in order to kill microorganisms. There is no doubt that pasteurisation adds an additional step in the overall manufacturing process, but if well designed it should not slow down throughput or place additional management burdens on the plant. The use of continuous pasteurisation systems mean that the process is simple and the potential for product damage or change in quality is minimised.

Myth 3: Pasteurisation is only suitable for simple fluid materials

Pasteurisation can be used on a wide variety of liquid and semi-liquid materials. While simple Newtonian fluids will be the easiest to work with, and can often be effectively pasteurised with a simple plate heat exchanger, there are solutions for almost any material. HRS developments such as the use of corrugated tube and scraped surface heat exchangers means that we can deal with anything from viscous fluids requiring gentle handling or with low rates of heat transfer, to complex mixtures.

Myth 4: Pasteurisation requires a lot of energy

The amount of energy used in food pasteurisation is highly variable, depending on the process used, the nature of the material being treated and the heat exchanger used. The bulk of any energy requirement is used to raise the temperature of the foodstuff. Traditional pasteurisation units simply dump this heat afterwards, meaning they are incredibly wasteful and inefficient. Where possible, HRS heat exchangers recapture the heat and use it again, making them up to 70% more efficient than some traditional systems.

Myth 5: Pasteurisation equipment is high maintenance

The use of corrugated tubes, together with integrated cleaning-in-process (CIP) minimises the amount of fouling and therefore the amount of cleaning necessary to maintain the efficiency of HRS pasteurisation systems. The careful design of static tubes also helps the production (and therefore purchase) costs.

Myth 6: You cannot pasteurise viscous fluids

Subjecting viscous and non-Newtonian fluids, such as cooking sauces, to shear stress during the manufacturing process can damage the quality and texture of the material which may preclude the use of certain designs of heat exchanger for pasteurisation. However, by choosing a system such as the HRS Unicus scraped surface heat exchanger which prevents fouling while maintaining relatively low pressure, such unwanted effects can be overcome.

Myth 7: Pasteurisation is the same as sterilisation

Unlike sterilisation, pasteurisation does not completely eliminate microorganisms which may be present in the foodstuff. Pasteurisation reduces the microbial load by a significant factor (for example by 5-logs) which in normal circumstances reduces the level of contaminating pathogens to a level at which they do not pose a hazard.

* High Temperature, Short Time and Low Temperature, Long Time

** https://www.tycois.com/wps/wcm/connect/ab4fd1f4-4aa2-45a3-a4f1-b91b36539e0f/LT1000-02FoodDefenseWP_Part2_hireresDigital.pdf?MOD=AJPERES

*** http://www.thegrocer.co.uk/journals/2012/10/12/u/k/f/FD-Thought-Leader-v2_14.pdf

****http://www.stericycleexpertsolutions.co.uk/listeria-hysteria-contamination-risks-driving-food-recalls/

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