Thermal Food Processing

Thermal Processing of Canned Foods 339
Discharge
Infeed
FIGURE 11.3 The process principle of FMC FoodTech continuous rotary (reel-and-spiral)
sterilizer system. Left: System cut-away diagram. Right: Induced convection heating.
major concerns. To obtain a desired throughput, many batch retorts are often
necessary, which requires plant floor space and increases the energy consumption,
especially during venting and come-up phases.
11.2.2 CONTINUOUS ROTARY STERILIZER
Fast Axial Rotation (~90°)
The continuous rotary sterilizer is a fully automated continuous processing system
designed for high product throughput, lower energy consumption, and more
uniformity of processed product quality. The continuous rotary sterilizer system
uses the induced heating principle by intermittently rotating the can along its axis
(side), and thus increases the rate of heat penetration (Figure 11.3). The system
enables use of the high-temperature short-time process principle for maximizing
the product quality and throughput.
The seamed cans enter the line directly from the closing machine. A feed
device delivers the cans via the infeed valve to the rotating reel of the sterilizer.
The reel, working in conjunction with the stationary spirals in the shell, carries
the cans through the cooking and cooling system. 4 Since each container travels
exactly the same trajectory, its process time and temperature profile and cooling
profile are exactly identical. Uniform cooking/cooling and uniform quality for every
container can thus be ensured. The continuous rotary sterilizer is widely used in
the food industry. More than 7500 FMC FoodTech continuous rotary shells have
been placed in production around the world since 1921 for processing more than
half of the world’s canned foods. The major applications are for fruit, vegetables,
ready meals, soups, infant formula, and dairy products. Depending on the process
time and can size, the system can deliver up to 1500 cans per minute.
To meet the industry demands on reducing the overall cost and increasing the
consumer convenience, the continuous rotary sterilizer is consistently evolving.
Figure 11.4 shows the FMC FoodTech continuous rotary sterilizer, with overpressure
capability for handling different packaging formats, such as plastic containers,