Pasteurization 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 pasteurization has increased.
At the same time, the technology has also improved, with developments in the equipment used for High Temperature, Short Time (HTST) and Low Temperature, Long Time (LTLT) methods. While simple plate heat exchangers may still be suitable for the pasteurization 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 dispel eight popular myths about food pasteurization:
Myth 1: Pasteurization Is Expensive
While the exact costs will vary with each installation, there is no doubt that there is a capital cost to pasteurization. However, compared with the potential losses due to food spoilage, or worse a food safety incident, these costs are insignificant. In the U.S., the costs of recalling food products have been shown to average $10 million*, before accounting for brand damage. Last year alone, 24 recalls due to E. coli, Listeria monocytogenes and Salmonella resulted in the destruction of almost 700,000 pounds of food products.**
Against these potential costs, the capital cost of a corrugated tube heat exchanger-based pasteurization system is a sound investment. Alongside the capital costs, the running costs of a pasteurization unit need to be considered.
Myth 2: Pasteurization Is Too Complex
Pasteurization 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 micro-organisms. There is no doubt that pasteurization 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 pasteurization systems mean that the process is simple and the potential for product damage or change in quality is minimized.
A pasteurization system at a tomato processing plant.Myth 3: Pasteurization Is Only Suitable For Simple Fluid Materials
Pasteurization 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 pasteurized with a simple plate heat exchanger, there are solutions for almost any material. Innovations, such as the use of corrugated tube and scraped surface heat exchangers, means that a company can deal with anything from viscous fluids requiring gentle handling or with low rates of heat transfer, to complex mixtures, such as curd cheese, which could otherwise foul the heat exchanger, reducing thermal efficiency and requiring regular cleaning and maintenance.
Myth 4: Pasteurization Requires A Lot Of Energy
The amount of energy used in food pasteurization 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 pasteurization units simply dump this heat afterwards, meaning they are incredibly wasteful and inefficient.
Myth 5: Pasteurization Equipment Is High Maintenance
The use of corrugated tubes, together with integrated cleaning-in-process (CIP), minimizes the amount of fouling and therefore the amount of cleaning necessary to maintain the efficiency of pasteurization systems. The careful design of static tubes also helps to keep down production (and therefore purchase) costs.
Pasteurization can be used for viscous fluids such as pasta sauces.Myth 6: You Cannot Pasteurize 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 pasteurization. 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: Pasteurization Is The Same As Sterilization
Unlike sterilization, pasteurization does not completely eliminate micro-organisms which may be present in the foodstuff. Pasteurization reduces the microbial load by a significant factor (for example by 5-logs) which in normal circumstances reduces contaminating pathogens to a level at which they do not pose a hazard.
Pasteurization need not be overly onerous or detrimental to the quality of the product. Certainly, with the correct choice of equipment, pasteurization does not need to have a negative effect on plant throughput or efficiency and a well-designed system incorporating heat regeneration and corrugated tubes should enhance the overall facility, helping to add flexibility to your business.
** https://www.fsis.usda.gov/wps/portal/fsis/topics/recalls-and-public-health-alerts/recall-summaries
About HRS Heat Exchangers
Headquartered in the UK, HRS Heat Exchangers Ltd operates at the forefront of thermal technology, offering innovative and effective heat transfer solutions worldwide, across a diverse range of industries. With over 35 years’ experience, we specialize in the design and manufacture of an extensive range of tubular, corrugated and scraped surface heat exchangers. All our products are designed in accordance with the ASME standard. HRS has a network of offices throughout: Spain, USA, Malaysia, Australia and India; with manufacturing plants in the UK, India and Spain.
