Because cold temperature processing is so critical to many food processing operations, improvements in technology can significantly impact productivity and profits. High volume processors often can save hundreds of thousands or more in hard, direct costs when switching from mechanical freezing methods to high efficiency batch or inline chillers and freezers that use carbon dioxide (CO2) or liquid nitrogen.
Over the past few years, cryogenic freezing and chilling technology has experienced a step-change in advancements and become more efficient in a number of ways. New immersion-spiral freezing technology combines high efficiency nitrogen utilization with high volume throughput. These freezers offer the best of both worlds, leveraging both the liquid and gaseous phases of nitrogen in a unified two-stage process to maximize cryogen efficiency. The nitrogen bath instantly crust freezes products to lock in moisture, shape and quality — and helps prevent individual quick frozen (IQF) products from clumping and sticking. Proprietary airflow design also helps to maximize cryogen use and results in lower operating costs.
The impact of cryogenic advances can be pervasive, improving production capacity and overall competitiveness well into the future. A single immersion spiral freezer can process up to 20,000 pounds of food per hour. If properly designed, some nitrogen impingement freezers offer the highest freezing capacity per square foot of floor space. Customized solutions can be developed based on either CO2 or nitrogen, depending on which cryogen is best for the process and the plant.
More efficient freezing operations also can streamline downstream processes. For example, a precise crust-freezing method for deli logs using a hygienic, cryogenic (CO2) tunnel freezer helps West Liberty Foods increase production rates and improve the quality of slicing on a new high-speed deli-log slicer at its plant in Mt. Pleasant, Iowa. Just the right temperature and depth of crust-freeze on the deli log ensures the blade gets a clean “bite” for consistent slicing, even stacking and a significant reduction of fines. That kind of precision can help avoid bottlenecks and eliminate product losses.
Whether downstream or in the freezing process itself, reducing losses — even a few percent — can add up to hundreds of thousands of dollars a year on high volume processes. These savings become even more important with the rising cost of proteins and other raw ingredients.
A cryogenic system designed to individually quick freeze diced poultry and other small or fragile items can offer benefits not possible with existing flighted freezers. For example, one cryogenic freezer helps protect IQF product and uses a proprietary rolling-wave action to keep IQF products separate as they freeze.
Modern cryogenic solutions also can help processors get more productive capacity out of the same floor space. A proprietary crossflow air design on a new type of cryogenic spiral freezer, for example, is said to improve processing efficiency by 10 percent or more compared to existing cryogenic spiral freezers. The space-saving design utilizes cryogenic gases efficiently and chills food at an even rate. Because the belt spirals through a cylindrical space rather than a box, the freezer uses less stainless steel, which reduces solid-state thermodynamic losses. The smooth shape also contributes to the proprietary airflow pattern and helps ensure more consistent product temperatures across the conveyor belt.
Incorporating modern cryogenic solutions into food processing operations can sometimes free up valuable floor space by folding two or more freezing lines into one. This was accomplished recently for Tip Top Poultry, Marietta, Ga., on its IQF diced chicken line.
Preserving Product Quality
Cryogenic processing equipment also can help retain product quality during the freezing process. Moisture retention is critical. For marinated products such as chicken breasts, cryogenic processing helps lock in moisture and retain shape after pressing, which adds to the overall product value. Moisture losses can mean not only lost profit due to lower packing weight, but also a loss of the quality and flavor that customers expect.
While there are physical limits to how quickly some foods can be chilled or frozen, cryogenic food processing experts can customize freezers/crust-freezers and chillers to meet specific product needs and then fine-tune operating parameters to optimize production. Modern cryogenic spiral freezers, for example, can equilibrate baked items at a controlled rate to help maintain internal cell structure for higher quality, better freshness and improved shelf life. Bottom-injection chilling systems for ground-protein products can chill ingredients from the bottom of the mixer with liquid nitrogen or CO2 snow faster and more consistently than top-chilling methods while reducing chilling costs. More consistent temperatures also can reduce belt sticking and hangups for downstream patty-making equipment.
Because recent advances in cryogenic technology are improving quality, efficiency and productivity, these developments play a pivotal role as older freezing equipment is outmoded and replaced. Cryogenic food processing experts can review existing operations and estimate “hard” dollar cost savings for new installations and retrofits. Laboratory analyses can pre-test and pre-qualify the new freezing/chilling solution and process parameters on specific food products.
System optimization is essential for maximizing performance, so a quality installation — from the location of the cryogenic storage tank to the engineering of cryogenic piping and exhaust systems — is paramount. Optimization is especially critical for retrofits such as bottom-injection chilling systems for mixers, where even existing systems just a few years old might benefit from an upgrade.
In large-scale operations, lowering the cost to freeze often is enough for decision making. However, any of a range of potential “soft” savings — smaller footprints, simplified maintenance and improved product quality, for instance — also may apply. Though sometimes more difficult to quantify, these soft benefits can be equally — if not, more — important to food processors.
Kayem Foods, for example, needed to quickly boost capacity in a tight space, so a impingement freezer was identified as a suitable choice for its sausage plant in Woburn, Mass. More broadly, attention to food quality and safety is increasingly making hygienic design a differentiating factor in equipment decisions.
A full appreciation of both hard and soft savings can make decisions on new technology solutions straightforward for all those involved, from the plant floor to the front office.