Технологии предохлаждения становятся умнее: как автоматизация помогает экспортерам продлевать срок хранения урожая

Pre-cooling technology is becoming increasingly precise and automated, giving fresh produce exporters more control over how different products are cooled after harvest, says Sean Roche, managing director of UK-based vacuum cooling provider Cold Change Group. More precise control over cooling "One of the biggest developments I've seen in pre-cooling is not necessarily a completely new method of cooling, but how much more intelligent, efficient and controllable the equipment has become," Roche says. "Vacuum cooling, hydro cooling, forced-air cooling and blast chilling have all existed for many years. What is changing is the technology around them. At Cold Change Group, we've developed our technology using variable-speed drives, improved refrigeration controls, PLC-based automation, product-specific cooling programs and remote data logging to give the operator much better control over the process." Different crops require different cooling conditions, which is making product-specific programmes increasingly important, Roche explains: "With vacuum cooling in particular, we can now optimize the cooling cycle very precisely. As growers are expanding into different crops, they often have two or three different types of product to cool. For example, they might grow broccoli, cauliflower and cabbage. Different products behave differently under vacuum and, for ultimate optimization, there will be different settings for the cooling process." © Cold Change Group "The settings depend on the product itself, the weight, moisture content, and density of the product. For example, this could mean the refrigeration system needs to engage earlier or later in the cycle in order to complete a perfect cooling cycle. If this is not done correctly, the product could lose too much moisture during the cycle, which could ultimately affect the quality." Automation is also helping make this level of control easier to apply in daily operations, Roche says: "Rather than simply switching a machine on and running every crop through the same cycle, our programs are developed for individual products, temperatures and load conditions. The operator can select the product they would like to cool during a particular cycle, and the machine automatically controls the process. This is all done via a very simple-to-use touch screen tailored exactly for each customer's operation." Alongside cooling performance, energy consumption has become an important consideration in the development of pre-cooling systems. Roche states: "There is little benefit in saving fresh produce from post-harvest losses if the cooling process itself is unnecessarily energy intensive. We have done many years of research and development investigating the complete system, including vacuum pumps, refrigeration, water use, heat recovery, controls and cycle times." For exporters, the speed at which field heat is removed remains central to preserving the condition of the product after harvest, Roche explains: "Fresh produce begins deteriorating from the moment it is harvested. The key is, the faster the field heat is removed, the longer the shelf life and the better the quality of the product." Choosing the right pre-cooling method Selecting the right cooling method can therefore have a considerable impact on both operating costs and product quality. According to Roche, there is no single system suited to every crop: "I believe the biggest challenge is selecting the right type of pre-cooler for your products. There isn't one pre-cooling technology that is ideal for every type of fresh produce. Leafy vegetables may be extremely well suited to vacuum cooling, while other crops, for example cherries, grapes, apples and carrots, may benefit more from hydro cooling, forced-air cooling or blast chilling." Roche recalls an example in which changing the cooling method substantially reduced cooling times for a leafy product: "I have had instances where I have visited a customer, and they have been using blast chilling or forced-air cooling to cool leafy greens in packaging for years. The cycles took up to 10 hours, and this was extremely energy intensive. Changing to a vacuum cooler took their cooling times down to 17 minutes, from 20°C to 4°C. The savings on the energy bills alone paid for the vacuum cooler within a very short period. The quicker cooling time increased the shelf life by four days, and the quality was dramatically improved." © Cold Change Group The example illustrates why the choice of technology should be based on the product and operation rather than simply on the equipment available from a particular supplier, Roche explains: "We're the only company in the world that sells four different types of pre-coolers, covering almost every type of fresh produce. We'll advise a customer on the correct pre-cooler for their product specifically. A major mistake some people make is choosing themselves and approaching, for example, a blast chiller company who will try to sell them their chiller, regardless of whether it's correct for their operation." Pre-cooling also needs to be considered separately from simply placing produce in refrigerated storage, Roche says: "The importance of pre-cooling cannot be overlooked. A conventional cold room may eventually cool the product, but that does not necessarily mean it has been cooled effectively. The longer field heat remains in the product, the more valuable shelf life can potentially be lost before the produce even starts its journey." Making systems easier to operate and support is another area where further improvements are possible, Roche explains: "The opportunity now is to make these systems increasingly automatic. Operators shouldn't need to understand the refrigeration engineering behind the machine. Ideally, they select the product or programme and the control system manages the cooling process for them. Remote monitoring and diagnostics can also allow manufacturers and engineers to support equipment thousands of miles away, which is particularly valuable for exporters operating in remote growing regions." For that reason, Roche believes cooling requirements should be considered before a packhouse is built or expanded: "Pre-cooling needs to be considered at the design stage of a packhouse. You need to understand what is being harvested, the quantity arriving per hour, its incoming temperature, the required final temperature and how quickly it needs to reach that temperature. Only then can you determine the correct technology and capacity." Pre-cooling starts the cold chain The role of pre-cooling extends beyond the packhouse itself, particularly once produce enters longer and more complex supply chains. Roche continues: "In my opinion, this is where the real value of pre-cooling is sometimes underestimated. The cold chain doesn't begin when a refrigerated truck arrives at the packhouse or when a container is loaded onto a ship. It should begin as close to harvest as practically possible." © Cold Change Group Roche emphasizes that the temperature of the product at the start of that journey can affect every subsequent stage. "If produce enters the cold chain carrying significant field heat, every stage afterwards is effectively trying to recover from a poor start. Refrigerated storage, trucks, and shipping containers are generally much better at maintaining an established product temperature than trying to remove large amounts of field heat from fresh produce. Effective pre-cooling changes that. If the product is rapidly brought to its optimum temperature before storage and transportation, the rest of the cold chain is starting with produce already down to temperature, and its only job is maintaining that temperature." Longer shelf life can open new markets Additional shelf life can also create opportunities to serve more distant markets and reconsider transport options, Roche explains: "With a proper pre-cooling setup, the user can utilize the additional shelf life and reach markets further away from the place of origin, ultimately allowing them to expand their business. There can also be an important economic argument. Air freight is extremely fast but expensive. Sea freight is generally considerably slower but can be much more economical. If better post-harvest cooling and cold-chain management gives an exporter enough confidence in the condition and remaining shelf life of their produce to use longer transport routes, the economics of exporting can change significantly." © Cold Change Group Roche therefore sees pre-cooling as part of the wider effort to protect the value of produce throughout its journey: "For me, that is the bigger picture. Pre-cooling should not simply be viewed as another piece of refrigeration equipment or another cost in the packhouse. It is the first stage of protecting the value of everything the grower has spent months producing. And when you are exporting fresh produce locally or thousands of miles, getting that first stage right can influence everything that follows," he concludes. For more information: Sean Roche Cold Change Group Tel: +44 7912691713 (whatsapp) Tel: +447768795866 [email protected] www.coldchange.com