How food products are packaged and the types of food processed are two factors used to determine the difference between Ultra High Temperature (UHT)/aseptic packaging and autoclave sterilization. However, Allpax now offers the Shaka system, an autoclave processor capable of producing UHT quality food through a batch retort process. Benefits of the Shaka system include lower capital and labor costs, faster time to market, and great flexibility than aseptic processing.
The Shaka process agitates packaging with a six-inch double-stroke reciprocating movement. This rapid agitation produces intense movements equivalent to as high as 2-3 gs of force. The end result is a uniform internal heat map within the package. At speeds greater than 100 double strokes per minute, the Shaka process offers outstanding heat transfer, eliminating the traditional cold spots.
The Shaka basket orients packaging with pouches, cans, and trays horizontally. Heat transfer is not affected by the size of the package because of the outstanding thermal distribution. Any air bubbles dig into the product, facilitating the thermal distribution by continuously displacing the product to the container walls. The optimal speed for the Shaka agitation is about 100 to 180 six-inch double-reciprocating strokes per minute. For example, 400gm cans of vegetable soup heated to 250 degrees Fahrenheit in a static autoclave require about 50 minutes of sterilization time. Comparatively, Shaka agitation uses 180 reciprocating double strokes per minute, which reduces process time by as much as 90 percent, requiring 5 minutes of sterilization time. Therefore, products have a higher quality in terms of appearance, taste, and texture.
The patent for the Shaka process was developed by Zinetec Ltd. several years ago and licensed by Allpax. Five years of research and development brought a production machines to the market in 2013. The production unit is a single-production size basket with a capacity of 3,000 pounds of product. This equates to a small footprint Shaka autoclave with 3 to 6 batches per hour processing 9,000 to 12,000 pounds of product per hour.
To better meet the specific needs of customers, Shaka autoclaves can execute steam, water spray, or steam-air-thermal processes and accommodate packaging types including plastic cups, cans, trays, cartons, pouches, bottles, glass jars, and smaller food service containers. In addition, manual and automatic options are available for loading and unloading the autoclave.
The Shaka process offers improvements to the flexibility of containers produced compared to those by UHT processing/aseptic packaging. Texture, nutrient retention, taste, color, and cooking values over an array of products showed little differences between products Shaka processed and aseptically processed. While UHT process sterilization times are measured in seconds, Shaka process times are calculated in minutes. However, if the higher temperatures and the residence time for products passing through tubular or scraped surface heat exchangers in the aseptic process are calculated, the overall heat exposures of foods in the two systems are comparable.
One of the benefits of the Shaka process is increased flexibility in the range of food products capable of handling. Unlike UHT, the Shaka process can be used with foods containing particles of any size, which avoids FDA and other regulatory limitations on particles. Thus, sauces, soups, dips, ready meals, baby food, spreads, and pet foods will sterilize quickly.
Whereas UHT plants are limited in range of products processed, the Shaka process makes changing from one product or pack to another quick and easy. When processing flavored milks, for example, a UHT plant would require expensive changes to process milk-based desserts, limiting the types of products that can be packed at a given plant.
Two challenges of UHT processing/aseptic packaging include complexity of operation and higher capital cost. Capital costs are typically difficult to determine with accuracy due to confidentiality. However, upon research conducted for this report, the UHT processing/aseptic packaging plats cost roughly 50 to 100 percent more than conventional packing lines utilizing autoclave sterilization. In regards to complexity of operation, both UHT processing plants and aseptic fillers have a higher level of complexity as opposed to most food packing plants. This affects recruiting and training of staff and commissioning periods.
While UHT is beneficial for high volume product of a limited range of similar products for an established market, Shaka processing offers low capital cost and flexibility.