Refrigeration in the preservation of food is one of the factors that influences its quality, making it possible for them to have or not all the physical properties and nutritional values they must have. Some products such as soft drinks require refrigeration only in the production process, not in transport or on display, but others such as dairy and meat need a good cold chain to be able to "live".
by Ana María Restrepo
Meat, for example, due to its chemical composition, rich in proteins, lipids and its water content, is subject to the growth of microorganisms, but in turn lipids make it susceptible to oxidation, so that refrigeration processes (temperature and humidity) must prevent this from happening.
In the poultry industry refrigeration plays a very important role, not only because it helps to maintain the product and its quality, but because in a certain way the economy of the industry depends on it, that is, a good refrigeration directly benefits the product making it fresher, more durable and preserving its properties, while a bad cold chain will weaken the product and therefore its quality and price.
One of the most perishable products is poultry meat, therefore it is necessary that all the processes that make up the refrigeration chain are fulfilled, from cooling after slaughter to delivery to the consumer, through freezing and transport.
To talk about refrigeration processes and their importance in the poultry industry, AC/R LATINOAMÉRICA spoke with Giovanni Torres, general manager of Indisem, Florentino Torres M, plant manager of The Campollo S.A., and Daniel Rodríguez, head of refrigeration engineering at Johnson Controls.
A refrigeration plant for the poultry sector must be chosen according to the size of the poultry processor, and must comply with the standards of the regulatory bodies of each country. Giovanni Torres explains that refrigeration is used in this sector to delay degenerative changes, mainly those caused by microbes in the product.
For his part, Florentino Torres states that the choice of the refrigeration plant depends on the specific need of the type of marketing of the chicken, whether it is fresh or frozen, or the whole chicken or in parts, which in turn allows to define the amount of energy necessary for the cooling and / or freezing process of the same and storage.
As mentioned, in this industry there are several processes of the cold chain and each one is different, as an example, Daniel Rodríguez explains that after the sacrifice a rapid cooling is required that is usually done with cold water, which is cooled in chillers or using flake ice, there the chicken is immersed to lower its temperature in an efficient way. These chillers are adapted to work with the corrosive load of the water-blood mixture. "Normally these teams have a very large capacity when they work only during the net time of the process."
Ammonia, preferred refrigerant
For this type of industrial refrigeration, ammonia is the refrigerant chosen, not only because of its costs but because it does not destroy the ozone layer and does not contribute to the greenhouse effect associated with global warming, it is a compound that is found in nature and its release into the atmosphere is immediately recycled. Economic, but the efficiency of industrial ammonia systems is higher than those using Freon.
Rodríguez states that Freon systems come for relatively small capacities and ammonia systems for medium and large capacities, so many small systems could be used to form a large one with Freon, but this is not very economical, "this is the typical case of many plants in Colombia, which began as very small with small refrigeration systems and as they grew they began to install more and more small freon systems. In the end, the costs of energy, refrigerant and even maintenance themselves become unmanageable. Solution: Swap all these small systems for a large, normally centralized ammonia system."
Another aspect that is taken into account when using one or another refrigerant is that the disorderly and rapid growth that the poultry industry has had in Latin America has caused many types of refrigerants to be used. In this aspect, Florentino Torres explains that if the plant is located near or within an urban center, the use of ammonia as a refrigerant is avoided due to the management that this implies and the possible danger that it may generate to the environment of the plant due to its contamination, which is why freones 507 is used, 404 and 22. Each depending on the application. Although Freon 22 has restriction, it is still widely used by the industry in Latin America.
It also ensures that installation decisions are made seeking the greatest economy in the purchase and assembly of the equipment and not in its efficiency and low cost of operation in the future.
For his part, Giovanni states that ammonia is the most suitable refrigerant, despite the fact that refrigerants such as CFCs, HCFCs and HFCs are used.
As for the choice of fluid for the refrigeration process, this professional explains that it must result from a compromise between a large number of properties, which can be classified into two main groups:
* Thermodynamic and heat transmission properties, which play an important role in the conception, efficiency and energy performance of the facilities.
* Physical, chemical, environmental and physiological properties, which determine the choice of materials and measures to ensure the safety of equipment and people.
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High quality chickens As we mentioned before, the poultry refrigeration process is not one, but depends on the multiple stages of production, and the way the chicken is delivered to the consumer, in such a way that in this industry different phases and refrigeration systems are carried out. The General Manager of Indisem states that the cooling of the chicken after blanching is done in a chiller, which removes the heat from the chicken with the melting of crushed ice or cold water at 1ºC against flow. Then it goes to the conservation of the refrigerated chicken where it must be kept at temperatures of 0 and 2 GRC, a process that can be by direct expansion, flooded or recirculated. The refrigeration for marinated chicken is at -2 GRC, the chicken is made a thermal shock closing pores either in IQF (Individual Quick freezen), stationary tunnel (blast freezer) or continuous tunnel, which are also used for the freezing of whole chicken or depressed chicken at -18 GRC. On the other hand, in the process rooms, corridors and loading areas, the temperature must be maintained at 12 GRC and 5 GRC respectively. This cooling is achieved with primary or secondary refrigerants such as water recirculation or propylene glycol. Daniel specifies that it is important to maintain the cold chain after slaughter until consumption to avoid microbiological problems. For this reason in the process rooms a low temperature must be maintained but also comfortable for the operators. He also states that the ideal is to control the variables of humidity and microbial load. "For this there are certain equipment that are special air handlers that in addition to controlling humidity have filtering systems and ultraviolet light that improve the air quality of these rooms." When the product is classified and packaged, two types of storage can be carried out, one for the short term and one for the long term. For short-term refrigeration, refrigerated rooms are used that are kept between 0C and 2C. "As the product is packaged, the humidity and bacterial load of the air are not very critical. Sometimes the cooling system used to generate ice or cool water in the process also serves to keep the cold air in these rooms," explains Rodríguez. In the case of freezing chicken for long-term storage, it is best to use rapid cooling systems whose characteristic is to use very low air temperatures. This makes the freezing time of the product very short and consequently the size of the ice crystals in the chicken cells is very small. "If the ice crystals were very large (using slow freezing) these would break the cell walls and at the time of thawing the chicken to consume it would dehydrate considerably" says JCI's Head of Refrigeration Engineering. For this reason, the chicken quick freeze system must have temperatures below -27C and air speeds above 5m/sec, which prevents dehydration of the chicken before consuming it. In the same way, it is of vital importance that the cold chain continues in the transport trucks and at the point of sale, since the good process in the plant can be lost if the storage and transfer of the product is not adequate. Florentino explains that in the case of Colombia the transport of chickens is already refrigerated and in very good condition, In addition, the country's legislation on this matter covers this part of the chain, requiring minimum conditions, which are an insulated van in fiberglass (recommended material), with adequate refrigeration unit in capacity to cool the product. Features that endure If the refrigeration process is carried out as it should be, the product will retain its properties and quality, however if this procedure fails it will be reflected in the useful life of the product, the losses due to runoff or dehydration and logically in the sales and positioning of the company in the market. The dehydration of the product has two connotations, one from the point of view of the producer for whom if the chicken is dehydrated the grammage of the same is being lost, that is, money is lost at the time of sale; and the position of the consumer, because when thawing the chicken it loses size, it will have a texture too fibrous different from that of a well-processed chicken and in that water that was thawed a large part of the nutrients goes, leaving in the end a chicken of poor quality, hard, fibrous and without nutritional qualities. On the contrary, if the refrigeration process from slaughter to distribution and display is carried out correctly, the product will retain its properties. Florentino explains that chicken in its physicochemical composition can have up to 72% humidity, and it is key in the process to control the loss that this product may have, in order to have the largest number of grams per bird.
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Poultry industry in Latin America In Latin America, most poultry-producing countries, with the exception of Brazil, do not develop well compared to the United States and Europe. According to Florentino, the plants in the region have not been planned for more than five years, so there are no central refrigeration plants, but a large number of equipment of many brands, different capacities, different technologies, use of several refrigerants and different technical and assembly concepts. "The common denominator of poultry processing plants is to grow first in number of birds and then grow in refrigeration infrastructure, which leads many companies at certain times to use freezing and storage services of frozen product, purchase of ice, while making their own assemblies, to very high costs of these services and a very high decrease that affects the profitability of the companies". For his part, Giovanni believes that the implementation of refrigeration is in accordance with the growth of the market and the modernization of the plants in order to export the product. In the same way Daniel thinks, who affirms that poultry growth in the region is very strong in Brazil, followed by Mexico, Colombia, Argentina, Venezuela, Chile and Peru. In this order of ideas, the implementation of refrigeration systems and new technologies advances faster in countries with more industrial development. It should be noted that in Brazil, technological advances are joined by the research that is developed both in the poultry issue and in the stages of breeding and development of birds. As for other industries such as the American or the European, the poultry cold chain is very influenced by American technology in terms of the use of refrigerants and refrigeration systems, although there are also Asian brands not well known, but with good results according to those who have used them, as explained by the manager of the Campollo beneficiation plant. For his part, Giovanni affirms that refrigeration worldwide uses the same cycle, the difference lies in the implementation of technology in the processes, increasing their production levels and profitability according to the level of development of each country.
* Physical, chemical, environmental and physiological properties, which determine the choice of materials and measures to ensure the safety of equipment and people.
{mospagebreak}
High quality chickens As we mentioned before, the poultry refrigeration process is not one, but depends on the multiple stages of production, and the way the chicken is delivered to the consumer, in such a way that in this industry different phases and refrigeration systems are carried out. The General Manager of Indisem states that the cooling of the chicken after blanching is done in a chiller, which removes the heat from the chicken with the melting of crushed ice or cold water at 1ºC against flow. Then it goes to the conservation of the refrigerated chicken where it must be kept at temperatures of 0 and 2 GRC, a process that can be by direct expansion, flooded or recirculated. The refrigeration for marinated chicken is at -2 GRC, the chicken is made a thermal shock closing pores either in IQF (Individual Quick freezen), stationary tunnel (blast freezer) or continuous tunnel, which are also used for the freezing of whole chicken or depressed chicken at -18 GRC. On the other hand, in the process rooms, corridors and loading areas, the temperature must be maintained at 12 GRC and 5 GRC respectively. This cooling is achieved with primary or secondary refrigerants such as water recirculation or propylene glycol. Daniel specifies that it is important to maintain the cold chain after slaughter until consumption to avoid microbiological problems. For this reason in the process rooms a low temperature must be maintained but also comfortable for the operators. He also states that the ideal is to control the variables of humidity and microbial load. "For this there are certain equipment that are special air handlers that in addition to controlling humidity have filtering systems and ultraviolet light that improve the air quality of these rooms." When the product is classified and packaged, two types of storage can be carried out, one for the short term and one for the long term. For short-term refrigeration, refrigerated rooms are used that are kept between 0C and 2C. "As the product is packaged, the humidity and bacterial load of the air are not very critical. Sometimes the cooling system used to generate ice or cool water in the process also serves to keep the cold air in these rooms," explains Rodríguez. In the case of freezing chicken for long-term storage, it is best to use rapid cooling systems whose characteristic is to use very low air temperatures. This makes the freezing time of the product very short and consequently the size of the ice crystals in the chicken cells is very small. "If the ice crystals were very large (using slow freezing) these would break the cell walls and at the time of thawing the chicken to consume it would dehydrate considerably" says JCI's Head of Refrigeration Engineering. For this reason, the chicken quick freeze system must have temperatures below -27C and air speeds above 5m/sec, which prevents dehydration of the chicken before consuming it. In the same way, it is of vital importance that the cold chain continues in the transport trucks and at the point of sale, since the good process in the plant can be lost if the storage and transfer of the product is not adequate. Florentino explains that in the case of Colombia the transport of chickens is already refrigerated and in very good condition, In addition, the country's legislation on this matter covers this part of the chain, requiring minimum conditions, which are an insulated van in fiberglass (recommended material), with adequate refrigeration unit in capacity to cool the product. Features that endure If the refrigeration process is carried out as it should be, the product will retain its properties and quality, however if this procedure fails it will be reflected in the useful life of the product, the losses due to runoff or dehydration and logically in the sales and positioning of the company in the market. The dehydration of the product has two connotations, one from the point of view of the producer for whom if the chicken is dehydrated the grammage of the same is being lost, that is, money is lost at the time of sale; and the position of the consumer, because when thawing the chicken it loses size, it will have a texture too fibrous different from that of a well-processed chicken and in that water that was thawed a large part of the nutrients goes, leaving in the end a chicken of poor quality, hard, fibrous and without nutritional qualities. On the contrary, if the refrigeration process from slaughter to distribution and display is carried out correctly, the product will retain its properties. Florentino explains that chicken in its physicochemical composition can have up to 72% humidity, and it is key in the process to control the loss that this product may have, in order to have the largest number of grams per bird.
{mospagebreak}
Poultry industry in Latin America In Latin America, most poultry-producing countries, with the exception of Brazil, do not develop well compared to the United States and Europe. According to Florentino, the plants in the region have not been planned for more than five years, so there are no central refrigeration plants, but a large number of equipment of many brands, different capacities, different technologies, use of several refrigerants and different technical and assembly concepts. "The common denominator of poultry processing plants is to grow first in number of birds and then grow in refrigeration infrastructure, which leads many companies at certain times to use freezing and storage services of frozen product, purchase of ice, while making their own assemblies, to very high costs of these services and a very high decrease that affects the profitability of the companies". For his part, Giovanni believes that the implementation of refrigeration is in accordance with the growth of the market and the modernization of the plants in order to export the product. In the same way Daniel thinks, who affirms that poultry growth in the region is very strong in Brazil, followed by Mexico, Colombia, Argentina, Venezuela, Chile and Peru. In this order of ideas, the implementation of refrigeration systems and new technologies advances faster in countries with more industrial development. It should be noted that in Brazil, technological advances are joined by the research that is developed both in the poultry issue and in the stages of breeding and development of birds. As for other industries such as the American or the European, the poultry cold chain is very influenced by American technology in terms of the use of refrigerants and refrigeration systems, although there are also Asian brands not well known, but with good results according to those who have used them, as explained by the manager of the Campollo beneficiation plant. For his part, Giovanni affirms that refrigeration worldwide uses the same cycle, the difference lies in the implementation of technology in the processes, increasing their production levels and profitability according to the level of development of each country.
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