The process
The retort is loaded with baskets filled with packed food containers. The retort is brought up to sterilising temperature and a reciprocating actuator shakes the baskets and their contents back and forth vigorously. The vigorous agitation causes thorough mixing of the food in the container so the heat is rapidly transferred throughout the contents. All the containers in the retort undergo exactly the same degree of agitation.
Schematic view of the Shaka® process.
This thorough mixing and rapid heat transfer permits the use of higher sterilisation temperatures, without over-cooking or scorching on the wall of the container. Agitation also speeds the cooling part of the cycle.
The combination of the even, rapid heat transfer with the higher sterilisation temperature normally used in the Shaka® process leads to typical cook times of just 2-5 minutes and just 5-10 minutes total cycle times – ‘come-up’ – sterilisation – cool. With efficient material handling, a Shaka® process retort can sterilise several batches per hour!
The process sterilises food many times faster than conventional static or rotary retorting processes, with commensurate improvements in food quality.
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This table shows how quickly food container contents come up to sterilisation temperature when the agitation rates exceed 120 rpm, as used in the Shaka® process.
This table shows how quickly food container contents cool from sterilisation temperature when the agitation rates exceed 120 rpm, as used in the Shaka® process.
For most retail cans and pouches of soups, sauces and similar food products, just 2-5 minutes are needed for sterilisation and about 5-10 minutes for overall cycle times. Products containing particulates may take slightly longer to allow heat transfer in and out of the particle and the possible slowing of the agitation rate to protect the integrity of the particle. The Shaka® process is less suitable for solid pack products such as ham or tuna and for products requiring extended cooking.
Below are some typical times for come-up, sterilisation and cooling, for products packed in 400gm (73mm x 110mm) retail cans. Note the dramatic reduction in cycle time with the Shaka® process, leading to much improved food quality.
The Shaka® products taste fresh, with well-developed flavours and little or no discolouration. The Shaka® processed soups are bright, the vegetables retaining their distinctive colours and textures.
The Shaka® process also offers economies in processing – shorter cycles, energy savings of up to 50% and a much smaller factory footprint compared with conventional batch retorting processes. Complementary Know-How is available from Zinetec Ltd.
Two samples of Béchamel sauce: the one on the left was processed in a rotary retort and the one on the right was processed in a Shaka® process retort. Note the lighter colour of the Shaka® processed product.
Sterilisation times for large food service packs.
The Shaka® process dramatically reduces times for the sterilisation and cooling of conduction products such as vegetable soups packed in large food service cans and other packs. Note the difference in speed compared with static retort processing for large (4250 gm or 1 gallon) food service cans. Foods taste fresher and have far superior colour and texture.
Unlike the static processed foods, the Shaka® processed products tasted fresh, with well-developed flavours and little or no discoloration. the vegetables retaining their distinctive colours.
The Shaka® process also offers economies in processing – shorter cycles; energy savings of up to 50% and a much smaller factory footprint compared with conventional batch retorting processes. Know-How is available from Zinetec Ltd for Shaka® process users.