Precooling Is Essential for Many Types of Produce

After harvesting, it’s essential to properly cool produce in order to maximize its shelf life. By staving off the natural growth of microorganisms, the cooling process helps to slow the physiological changes which impact freshness and nutritional value. This can be achieved both through lower-cost and more advanced methods, including harvesting during cooler periods during the day, cool air ventilation, and evaporative cooling. For many types of produce, however, precooling is an essential part of the equation. Precooling is a process performed to rapidly remove field heat immediately following a harvest.

Field heat is described as the difference between the temperatures of actual crops harvested versus the ideal storing temperatures for those same food products. Prompt removal of this type of heat is essential, as even an hour-long delay can correlate with about a day’s loss in terms of shelf life. As the name suggests, precooling is performed in advance of the final, primary cooling method, and it can be performed in several different fashions.

Precooling Methods

There are various approaches to precooling, and while they vary in their effectiveness, any process which quickly lowers the temperature of harvested produce without damaging them is beneficial to some extent. SEMCO/SEMCOLD LLC provides a range of industrial cooling products, such as hydrocoolers which deliver efficient, economical performance to maximize yield and minimize loss.

Hydrocooling – Hydrocooling is one of the most common and effective precooling methods. Hydrocooling involves spraying produce or dipping it into chilled water. This method can work up to 15 times faster than air-cooling methods. Hydrocooling also does a better job of retaining moisture and can even utilize refrigerated calcium chloride solutions in order to prevent storage problems with certain fruits. Hydrocooling does require a clean, sanitary water source and is best used for flower, stem, and root-type vegetables as well as some tree fruits.

Some other common precooling methods are described below:

Shade Cooling – By moving produce to a cool, shaded area immediately after harvesting, an acceptable amount of precooling can sometimes be achieved, depending on the produce. If possible, create viable indoor holding areas such as within packing houses. Structures which are outfitted with light-colored or white roofs are also generally better for reflecting sunlight and reducing solar gain, lowering inside temperatures with minimal overhead cost.

Ice Cooling – Ideal for use during storage, distribution, and transport stages, ice cooling is an acceptable method of field heat removal, particularly when produce packaging is too dense for effective air-based approaches. As much of the cooling potential is lost via heat exchange with the general environment as opposed to the produce itself, ice is not generally regarded as a highly-efficient method of precooling.

Ice cooling can be performed in several different fashions, including top icing, applying crushed ice over produce, or liquid icing, injecting a slushy ice and water mixture into packages, or by wrapping ice bottles in paper and placing them amid produce, such as in situations where direct contact is to be avoided.

Specific Produce Types That Require Precooling

Precooling is an important step in the harvesting process for many fruits and vegetables. Among those that should always be precooled are the following:

  • Berries
  • Capsicum
  • Cherries
  • Chili peppers
  • Cucumbers
  • Eggplant
  • Grapes
  • Green beans
  • Leeches
  • Mandarin oranges
  • Melons
  • Okra
  • Peas
  • Sapotas
  • Spinach
  • Stone fruits
  • Tomatoes

Conversely, some types of produce do not typically require precooling. Such produce includes cabbage, carrots, cauliflower, green bananas, guava, mangoes, papaya, pomegranates, and radishes. Keep in mind these lists are not exhaustive but are helpful starting points for reference. For more detailed information about cooling and storage methods for specific types of produce be sure to check out our past articles.

More Information about Precooling

SEMCO/SEMCOLD LLC is a trusted manufacturer of custom-spec cooling systems for storage and transportation of all types of produce and perishable food products. We design hydrocooling technology which will help you to deliver more fresh, high-quality produce while reducing potential losses. Taking a careful, active role in cooling and precooling will help to improve produce taste, quality, and even economic value.

/by

Warning Signs of Fish Spoilage

A top priority for commercial fishermen is preserving their catch. Since they may not be returning to port immediately but moving on to other fishing spots, refrigeration and a well-insulated hold are vital in the effort to keep fish fresh. SEMCO/SEMCOLD LLC understands the importance of preventing fish spoilage, and we manufacture and install industrial cooling systems designed to customer specifications. In the commercial fishing business, proper cooling of the seafood product can mean the difference between expected profit and economic disaster. The warning signs of spoilage can typically be detected through the senses of sight and smell, but there are also other warning signs of fish spoilage.

Assessing the Quality of Fresh Fish and Warning Signs of Fish Spoilage

The term “quality” refers to the appearance and freshness of fish or the degree of spoilage that has occurred during the time of transport from sea to land. Though quality is something an individual can determine through sight and smell, food researchers have developed parameters that form the basis of an assessment tool known as the Quality Index Method (QIM). The various parts of a fish, such as the skin, eyes, and gills are rated. The QIM assigns a score of zero for very fresh fish and the numbers, or demerits, pile up as the fish deteriorates. Characteristics such as dull skin, cloudy eyes or a musty, sour odor are among the signs of fish spoilage. The QIM assessment has been used for many years by European and Nordic countries to evaluate how many days caught fish such as cod, herring, and flounder can be kept on ice while still remaining safe to eat.

Guarding Against Fish Spoilage

The hold of a commercial fishing vessel must be properly chilled in order to preserve the catch. Many types of insulation are available—polyurethane foam, fiberglass, cork board, even wood shavings—and SEMCO/SEMCOLD LLC can provide the accompanying cooling system depending on the kind of insulation selected, the size of the craft, the amount of space available, and the type of fish being caught. With the entire customized system in place, fishermen can go about their business, confident that there is ample protection against fish spoilage. The refrigeration equipment, coupled with the proper insulation, will maintain the correct temperature inside the hold.

Icing Down the Catch

Fish of good quality should have bright, shiny skin. Their eyes should be clear, their gills characteristically colorful, and they should carry a fresh, seaweed sort of smell. To ensure that they maintain good quality from the moment they are taken from the sea until the day of their delivery for packing and transport to a final destination, ice will be an important preservative. Ice, however, has its own issues. Since it is often handled with human hands, bacteria can invade the ice container, speeding up the spoilage process. SEMCO/SEMCOLD LLC offers ready-made clean ice that is available in several forms. Also available are icemakers that will produce ice continually as well as water filtration systems designed to ensure that the water used for the preservation of the catch is kept clean and organism free.

Different Kinds of Cooling for Best Preservation

Fish of different sizes have different needs relative to cooling methods. Small fish such as sardines and anchovies tend to spoil easily because they have few layers of protection. However, their small size allows for fast cooling. Medium-sized fish such as salmon, cod, or tilapia are less likely than smaller fish to spoil quickly and they stay cool longer than large fish. Meanwhile, large fish should ideally be gutted or filleted to make the cooling process more efficient. At SEMCO/SEMCOLD LLC, we understand these different requirements and stand ready to equip the commercial fishing industry with the ice, ice-making equipment, and refrigeration products they need to ensure the integrity of each valuable catch.

Discover the perfect ice solutions for your everyday needs.

✓ Experts in the industry

✓ reliable solutions

Contact Us
/by

Why Hydrocooling Won’t Work As a Standalone Produce Cooling Method

Proper cooling of produce is critical to maintain the quality and nutrition of food. The single most important factor that prevents food degradation is maintaining a proper food temperature. Through refrigeration by units produced by SEMCO/SEMCOLD LLC, major spoilage processes are prevented. The first is that the processes of ripening and premature softening are slowed at lower temperatures. Refrigeration also prevents wilting and moisture loss. Lastly, refrigeration prevents significant food quality and safety issue by preventing bacteria, fungi and yeast from growing. Among many cooling methods, hydrochiller is an effective pre-cooling method that aids in food quality.

The Hydrochiller Process

Hydrochillers are an effective process by which cooled water is used to bring the temperature of produce down. After produce is harvested, it can have a temperature between 50 to 80 degrees. This is commonly referred to as field heat. If the fruits, vegetables, and grains are not negatively affected by the process, they can be pre-cooled with hydrochillers.

Hydrochiller involves submerging produce in a tub of refrigerated water or passing produce through a stream of cooled water. Additionally, some machines will recycle to water used in the process while adding sanitizers to the water to help clean the produce as it is cooled. Water is more effective at quickly pulling heat out of produce compared to air-cooling. This allows field heat to be rapidly removed, slowing the spoiling process.

Limitations of Hydrochillers

Hydrochillers are a an efficient cooling process but does not work for all types of produce, is not as energy efficient compared to other methods at lower temperatures, and functions only as a pre-cooling and not a standalone cooling method. Certain produce should not be soaked or sprayed with water after harvesting. A few examples of fruit and vegetables that cannot be hydrochilled include celery, carrots, cabbage, blackberries and beets. In certain cases, the produce can be damaged by hydrochillers. In certain fruits and vegetables, extra water absorption by produce can also increase the speed of spoilage or decrease the structural integrity, taste, or quality.

Increased Speed and Decreased Energy Efficiency

Room cooling utilizes an air-conditioned room to bring down the temperature of produce. Hydrochillers are much more rapid than room cooling, but the hydrochillers process is not as energy efficient as room cooling. Maintaining a low water temperature required for the hydrochillers process take significant amounts of energy. This means that hydrochillers are a fast, efficient way of quickly removing heat, but it is not suitable for complete cooling to optimal temperatures because it would require too much energy.

Hydrochillers Are Not a Standalone Method

Hydrochillers are designed to quickly decrease the temperature of produce that is not sensitive to wetting, but it is not designed to maintain it at a low temperature. In addition to energy efficiency concerns, most produce could not be continually stored in cold water without significantly decreasing its stability, taste, and quality. To design an effective cooling process, hydrochillers should be an introductory method to decrease the temperature of sensitive produce rapidly so that it can be stored in a cold room and maintained at the correct temperature.

SEMCO/SEMCOLD LLC designs high quality cooling and freezing systems ideal for produce, food, and many other industrial and commercial applications. We are always happy to help our clients find the produce cooling system that is best for their needs. All of our systems are also customizable and can be designed to customer specs. For more information about cooling methods for specific types of produce please browse our past articles.

/by