Economics of high pressure processing.

An important criterion in the evaluation of preservation technologies is the cost per amount of treated product (Ting & Farkas, 1995). Although high pressure processing is a very promising technique for increasing product shelf life, it is more expensive than conventional methods such as high temperature sterilization. For this reason, high pressure processing is mainly used for niche products such as fresh fruit juices, seafoods, and guacamole. Currently, costs of the high pressure processing range from 10 to 20 cents per liter, whereas costs for high-temperature treatment may be as low as 2 to 4 cents per liter.

Cost reduction of the high pressure process can be achieved by careful consideration of the process. Important determinants of costs are capacity of the system (the number of liters processed per unit of time); the depreciation costs of the system; and variable costs such as labor, occupancy, and energy. A typical breakdown scheme for the total costs of the high pressure process is presented as follows:

area — 1-2%;

labor — 5-10%;

utilities, energy — 2-4%;

maintenance — 5-10%;

capital — 75-80%.

Area comprises the facility in which the processing unit is operated. Personnel includes the operators of the unit; the number of operators varies between 1 and 5, depending on the type of equipment. Energy costsre low and comprise less than 1% of total costs. Maintenance, which is mainly related to replacement of seals, is typically 4% of the investment costs per year. Thus, it is clear that capital costs are the main expense. A typical investment price fur a high pressure processing system (400 to 600 MPa) is SI.5 to S2.5 million. The capital costs of installing a high pressure processing system may be distributed as follows:

high pressure vessel, closures, and yoke — 50-60%;

pump and high-pressure circuit — 30-35%;

control — 10-15%.

Thus, the pressure vessel is the most crucial component of the unit.

In summary, cost reduction can be obtained only when at least one of the following objectives is achieved:

Capacity is increased. This can be accomplished in two ways: (1) Upscaling (Increasing the volume of the vessel decreases the cost price per liter. Kobelco reports that total costs per liter of product for a system containing a 500-liter vessel are 50% of the costs for a unit of 70 liters. Obviously, investment costs increase with vessel volume, but not linearly.); (2) reduction of the cycle time.

Investment costs are reduced. For this reason, the Barawing concept (van den Berg et al. 1998) focuses on reduction of pressure vessel costs in combination with a reduction of cycle time.

Answer the questions:

1. What are the advantages and disadvantages of high pressure processing?

2. Where is high pressure processing mainly used? Why?

3. Which method of food processing is more expensive: high pressure or high temperature one?

4. What do high pressure process costs include?

5. What is maintenance?

6. Why are capital costs the main expense?

7. How are the capital costs of installing distributed?

8. Is it possible to reduce the costs?

9. How is capacity increased?

10. How are investment costs reduced?