Methods of Meat and Seafood Preservation
When a consumer goes to buy any food products his/her first impression of the product is established from what they see. Among the things that a consumer observes are surface characteristics of the product, the color and form. Color is the most important of these characteristics and it highly determines if the consumer will be impressed by and purchases the product or not. The presentation, optical properties and physical form of meat and seafood products are therefore of very great importance to the industry at sale point. Texture and taste are also important properties that help to determine the quality of meat and seafood products. Preservation of these products is done for the purpose of extending the shelf life by permitting them to stay free of any bacterial decomposition for a long period. It is also done for the purpose of helping to maintain freshness in such products so that the texture taste and color of the preserved products match to those of freshly produced products (Nollet & Boylston 97-104).
Bacterial decomposition can be very hazardous to the consumer and in view of the dangers that would arise from consumption of infested or spoiled products; government and federal agencies have been involved in development and implementation of safety requirements in meat, seafood and poultry processing. The reason that bears most weight in preservation is therefore to give a product a long shelf life without spoiling. Salting of fish and meat products is one of the oldest methods used in food preservation. New technology has come up with other methods of food preservation such as ohmic heating, irradiation and microwaving to enhance older methods such as freezing or cold preservation, heat application, fermentation and evaporation and dehydration. However all these methods have their way of affecting food quality (Nollet & Boylston, 126).
Meat products are preserved through a combination of freezing, smoking and ozone techniques. Fish products for example are cut into sizeable portions that are then smoked, treated with ozone and then optionally frozen. Preservation of seafood in a way that will enhance shelf life and flavor has however proved to be a very difficult task. This is because the taste and quality of seafood is highly affected by oxidation and the tissue and cells of sea foods such as lobsters are disrupted by ice crystals. A freezing process for blue crabs has however been developed in which sugar is added to the boiling and cooling baths. This sugar is retained within the shell of the crab when it is being frozen and also during storage. Fish and whole seafoods are also injected with flavor enhancers, cryoprotectants and antioxidants before cooking or freezing in order to enhance the cooked yield flavor and shelf life. The materials are mixed with liquid and the solution is then injected into the body of fish or lobster for example such that the solution spreads out over the whole body. This injection is done at predetermined points and helps to prevent loss of original flavor, texture and also improve the quality of the frozen products. Spices also help to enhance flavor if they are injected into whole seafood and fish. S
ome of the spices such as mace and rosemary also act as antioxidants. Other types of spices used are such as soy sauce, jalapeno, onion, shallots, garlin, cayenne, leeks and butter forms. When freezing such products, it is important that proper packaging is used as this helps in preventing freezer burn. Freezing changes the color of bones and the meat around the bones but no color changes occur in poultry. In order to maintain freshness, it is important that fish and meat products are frozen as soon as possible (Nollet & Boylston 54-56).
In the beef industry various attempts have often been made in an effort to improve meat quality. One of the most promising methods is the swift and codeveloped in which papain, a proteolytic enzyme that has been clarified, standardized and concentrated is injected into the jugular vein of an animal before slaughter. The animal’s blood stream carries the enzyme to every part of its body resulting in increased tenderness. This process has however been limited to been in the attempt to tenderize it. Modified atmosphere packaging (MAP) is also used in meats and seafood products that have been stored in special plastic packages. The technique works by altering the mixture of gases such as carbon dioxide oxygen and nitrogen that are present in the atmosphere surrounding the place of storage of such foods. When the atmosphere is altered, the growth of fungi and bacteria that lead to spoilage of such products is limited and the plastic packages help to maintain this altered atmosphere for certain duration of time. But MAP has a disadvantage in that although it limits growth of harmful microorganisms it does not hamper growth of some bacteria that are otherwise harmful (Nollet & Boylston, 14-17).
The ozone and smoke process of preserving fish has proved to be a very effective method as it enables transportation of frozen and fresh sea food products from parts of the world that are otherwise very remote. Transportation is done in an economical way, is safe and sanitary conditions are good. The fish retains such characteristics as color, redness or brightness and to the consumer; it looks as if it has been freshly caught thus making it very appealing. In this process, fresh fish is first smoked and then treated with ozone and maybe frozen although this is optional. Smoke/ozone method helps in preventing decomposition by controlling bacterial formation and also helps to maintain the red color during the freezing process and in frozen storage. Optionally alcohol application can be done during this process by wiping the fish with alcohol either before smoking or after smoking has been done. Wiping with alcohol can vary from once or three times and helps to kill shallow bacteria on the surface of the fish. The duration of time spent in smoking fish varies depending on the thickness of the product. Vacuum chamber smoking also takes lesser time than ordinary smoking. Due to lack of oxygen in the smoking process, most aerobic bacteria are destroyed. Any bacteria left out during smoking are destroyed in freezing (Nollet & Boylston 25).
Another method used in preservation of meat and seafood products is food irradiation. This method of preservation has been in use since the early twentieth century and has been developed over the span of time. If properly applied, it is effective in reducing incidences of food borne diseases and also helps in preventing potential problems in the process of supplying the products. Irradiation and safety of such products but cannot reserve whatever spoilage may have occurred before application. During the process sea foods and meat are treated by exposing them to ionized radiation until the specific or precise dose has been absorbed into the product. Dosage varies depending on the type of product that is being treated and meat and seafood are treated with high doses exceeding 10KGy.
Radionuclide or machine sources are used in the irradiation process. Radionuclides are those radioactive materials such as caesium – 137 and cobalt 60 that produce ionizing gamma rays. X-ray generators and electron accelerators constitute some of the machine methods used in irradiation. Though these radiation energies result in changes in the chemical composition of the products, no nuclear changes occur that would cause radioactivity in the food. Chemical modification is also in a very low magnitude. The loss of nutrients is also in a very low magnitude. The loss of nutrients that takes place is to such a low extent that the nutritional value of the product is not interfered with (Nollet & Boylston 32-37).
Another method of preservation which is probably the oldest is drying. In this method water is removed from the meat products and this helps in preventing the growth of microbes. In meat the thickness is reduced to allow evaporation to take place from inside to the outside of the muscles. When loss of water takes place, the muscles shrink and get firmer but taste and flavor changes due to oxidation of fat. Dried meat is not a very pleasant product although it can be used in preparing soup powders. Salting is also a preservation method for meat and is done by either soaking the meat in 15-20% of brine which is referred to as wet curing or by dry curing in which the meat surface is rubbed with salt. Spices and sugar can be added to enhance flavor and color. The salt and sugar also act as antimicrobial agents.
Freezing is probably the most popular and widely used method of preservation. Freezing at a temperature level of 0 degrees F, helps to keep the products safe for consumption and storage in the frozen state causes minimal alteration to the nutrient value of meat and poultry products.
Nollet, .M. Leo & Bolyston, Terri. Handbook of Meat, Poultry and Seafood Quality. Blackwell