Advantages & Disadvantages of Food Additives
Food scientists have now learned that a number of factors relating to the food product and to the preservative conditions affect the efficiency of curing. Some of the food factors include the type of food being preserved, the fat content, and the size of treated pieces. Preservative factors include brine temperature and concentration and the presence of impurities. Preservative factors include brine temperature and concentration, and the presence of impurities. Despite the high number of traditional and modern methods still widely utilized to preserve food worldwide, alternative methods able to enssure a prolonged and safe preservation are necessary. Many of the current preservation methods impact the quality of food and change the regular form and aspect. The quality and safety of food deteriorate because of the inherent food properties or due to microbial contamination.
In the electrolytic process pure tin is used as the anode, and base steel plate serves as the cathode. Depending upon the number of anodes used and the speed of the plate in the electrolytic cell, the pickup of the can be regulated. Depending upon the different usages, the plate is given even or differential coating. In differential coating, the higher content of tin will always be on the surface coming into contact with the food.
It is also necessary to control the overpressure correctly to maintain a balance between the internal pressure developed during processing and the pressure of the heating system. The main plastic materials used for heat-processed foods are polypropylene and polyethylene tetraphthalate. These are usually fabricated with an oxygen barrier layer such as ethylvinylalcohol, polyvinylidene chloride, and polyamide. These multilayer materials are used to manufacture flexible pouches and semirigid containers.
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Nowadays a many readymade food products available in the market, how they are not getting spoiled until the expiry date mentioned in these products. Freezing to fend off food spoilageFood spoilage is caused by microorganisms, chemicals, and enzymes. In food industry, it is used to sterilize equipment and to kill microorganisms in air of food processing room. Low level of ionizing radiation is used to kill microorganisms on fresh fruits and vegetables.
Bacteria have the unique ability to form structures that are extremely resistant to harsh environmental conditions. These spores are resistant to freezing, high temperatures and other forms of drying. This makes them escape conditions in the conventional preservation techniques leading to the rotting of food.
4.1.4 Preservation techniques
However, to inactivate thermo-resisting spores ultra-high temperature pasteurization is more effective than VAT and HTST . During heat treatment of food items, minimal physical, chemical, or biological changes take place . After heating is done, the products are aseptically packaged in sterile containers . UHT pasteurized products have a longer shelf life than other pasteurized products.
- The main plastic materials used for heat-processed foods are polypropylene and polyethylene tetraphthalate.
- In fact, artificial preservatives such as sodium nitrate, sodium benzoate and propionate have long been used in food preparation because they are effective in small amounts.
- Almost all techniques of preservation are designed to extend the life of food by acting in one of these two ways.
- Unfreezable water contains soluble solids, which cause a decrease in the freezing point of water lower than 0 °C.
- Domestic demand for industry products is expected to grow particularly strong, specifically in developing economies, such as China and India.
- Sodium benzoate is very helpful in inhibiting the growth of potentially harmful bacteria, mould and other micro organisms in food, thus reducing spoilage.
Smoking meat and fish as a means of preservation grew out of cooking. After farming developed—the Neolithic Period, or New Stone Age—human beings had more dependable surpluses for preservation. Native Americans subsisted on dry corn and beans that they had stored for winter use; Plains Indians cut buffalo meat into thin strips and dried it in the sun on wooden frames. The search for methods of food preservation probably can be traced to the dawn of human civilization.
The science of freezing foods
Drying is one of the most ancient food preservation techniques, which reduces water activity sufficiently to prevent bacterial growth. Even traditionally salt-preserved foods do not meet the 10% salt requirement to stop microbial growth. But additional features about these foods, such as dehydration or addition of acid or preservatives , help prevent spoilage. In addition, many salt-preserved foods require refrigeration after opening in order to slow microbial growth. Exhausting is an important step to remove the air present in the product as well as in the container.
A food product is sterilized and then sealed in a sterilized container. Aseptic packages, including plastic, aluminum foil, and paper, are lighter and cheaper than the traditional metal and glass containers used for canning. Aseptically processed foods are also sterilized much more quickly, so their flavor is better. However, controversy has developed about the amount of disposable containers produced by this method. As with most methods of food preservation, freezing works better with some foods than with others. Fish, meat, poultry, and citrus fruit juices are among the foods most commonly preserved by this method. Foods may be contaminated by microorganisms at any time during harvest, storage, processing, distribution, handling, or preparation.
The burden of foodborne diseases
The air blast freezer is one the oldest and commonly used freezing equipment due to its temperature stability and versatility for several product types. In general, air is used as the freezing medium in the freezing design, either as still air or forced air. Freezing is accomplished by placing the food in freezing rooms called sharp freezers. Still, air freezing is the cheapest way of freezing and has the added advantage of a constant temperature during frozen storage, which allows usage for unprocessed bulk products like beef quarters and fish. However, it is the slowest method of freezing due to the low surface heat transfer coefficient of circulating air inside the room. Freezing time in sharp freezers is largely dependent on the temperature of the freezing chamber and the type, initial temperature, and size of product .
In 1810 an Englishman, Peter Durand, patented a can of iron coated with tin. Today’s cans are primarily steel, with a thin coating of tin and, usually, an enamel lining. Commercial canning began in the United States with pickles and ketchup in Boston in 1819 and seafood in Baltimore in 1820. The cooking in boiling water took five or six hours in the early days, but this was sharply reduced in 1860 when Isaac Solomon added calcium chloride to the https://personal-accounting.org/ water, raising its boiling point. The introduction of the pressure cooker, or retort, in 1874 was an even more important step, permitting much more rapid processing. Commercial canners then turned to machines that would do many of the tasks formerly done by hand, such as shelling peas, cutting corn from the cob, and cleaning salmon. Salting, which also inhibits bacteria growth, was a preferred method of preserving fish as early as 3500 b.c.
Water makes up over 90 percent of the weight of most fruits and vegetables. Water and other chemicals are held within the fairly rigid cell walls that give structure and texture to the fruit or vegetable. When you freeze fruits and vegetables you actually are freezing the water in the plant cells. Fresh fruits and vegetables, when harvested, continue to undergo chemical changes that can cause spoilage and deterioration of the product. This is why these products should be frozen as soon after harvest as possible and at their peak degree of ripeness.
- They can be used with or without outer cardboard cartons to protect against tearing.
- Sugars when dissolved in solutions act by withdrawing water from cells by osmosis, resulting in very concentrated solutions inside the cells.
- Therefore, an integrated approach would be useful to preserve food items during food production and processing stages.
- The prevention of the growth or destruction of pathogenic microorganisms or the microorganisms responsible for spoilage is basic to most methods of food preservation.
- Microorganisms also grow on plants and can contaminate food if care is not taken to remove them by washing or inactivate them by cooking.
- The history of ‘Food Preservation’ dates back to ancient civilization when the primitive troupe first felt the necessity for preserving food after hunting a big animal, which could not be able to eat at a time.
Therefore, it is a technology indicated for fresh food processing steps such as decontamination of fruits and vegetables and as a substitute for thermal treatments in juice processing. This chapter will discuss the impact of ultrasound on microbial counting, physicochemical parameters, enzymatic contents, bioactive compounds, and sensorial aspects of fruits and vegetable products. Is to prevent or to delay enzymatic and/or microbial changes in food so that the food is Food Spoilage: Causes, Food Preservation, Dis/Advantages and Examples available at some future time. A discussion of food preservation involves enzymes and microorganisms and the basic principles of preventing their activity in food. The principles are employed in several basic techniques of food preservation including applying heat; lowering temperatures, water activity, and pH; adding inhibitory substances; and irradiating the food. Controlled or modified atmosphere packaging may be used with any of the basic methods of preservation.
Once fire was discovered, prehistoric cave dwellers heat-dried meat and fish, which probably led to the development of smoking as another way to preserve these foods. Native North Americans produced a nutritious food called pemmican by grinding together dried meat, dried fruit, and fat. Mechanism and working principle HP process follows Le Chatelier’s principle and isostatic principle . According to Le Chatelier’s principle, biochemical and physicochemical phenomena in equilibrium are accompanied by the change in volume and hence influenced by pressure. Regardless of the shape, size, or geometry of the products, the isostatic principle relies on the instant and uniform pressure transmittance throughout food systems . HP processes affect all reactions and structural changes where a change in volume is involved.
Ice-crystals formed on surface of food evaporate and give mechanical damage on the surface of food. However, if larger ice-crystal are formed in food, it gives more mechanical damage to the food.
The time–temperature schedule for the required process lethality should be effective to eliminate the most perilous and heat-resistant mesophilic anaerobic spore-forming pathogen Clostridium botulinum. Post-process hygiene is of utmost importance for heat-processed foods as the heat-processed containers, which are still warm and wet, may lead to inward leakage through the seal.
Freezer burn occurs when frozen food gets damaged by ice crystal growth and dehydration, exposing food to oxygen. Physical signs of freezer burn are not the same as food spoilage mentioned above.
The thermal process is finally established by measuring the temperature at the container slowest heating point for a number of replicates that are placed in the cold spot of the thermal processing system. The data obtained are usually referred to as “heat penetration” data.
However, it is important to highlight that all preliminary steps before freezing food products are quite similar whether on a large or small scale. Furthermore, chapter 3 focuses more on the more suitable approach for small food freezing industry. In the tray pack method, chilled, well-drained vegetables are placed in a single layer on shallow trays or pans. Trays are placed in a freezer until the vegetables become firm, then removed. Tray-packed foods do not freeze in a block but remain loosely distributed so that the amount needed can be poured from the container and the package reclosed . The objective of blanching is to inactivate the enzymes causing detrimental changes in colour, odour, flavour, and nutritive value, but heat treatment causes loss of such characteristics in fruits .
What are the disadvantages of food preservation?
Dried food does not taste the same as fresh food does. Moisture can cause dried foods left in the food in the drying process or allowed in during storage can cause mold on food. Overly dried fruits, vegetables and meats can be exceptionally hard, often to the point where they do not soften.
Or, the food may be placed between two parallel refrigerated plates and frozen. Technology accounts for two main factors of ever increasing importance, extending product file and reducing the amount of additives used. MAP involves modifying the atmosphere surrounding the product inside the package. This in turn allows chemical, enzymatic, or microbiological reactions to be controlled and therefore reduces or eliminates the main processes of deterioration in the product. The package usually has a low permeability to gas, so that the initial concentrations of the added gases remain unchanged after the package is sealed.
No matter whether food is fresh or processed, the rate of its deterioration or spoilage is influenced by the environment to which it is exposed. The exposure of food to oxygen, light, warmth or even small amounts of moisture can often trigger a series of damaging chemical and/or microbial reactions. For example, storing foods at low temperatures reduces spoilage because both microbial and enzymic decay is faster at higher temperatures. This means that they have a very high water content and can support a lot of microbial growth. For example, meat has certain characteristics that may promote the growth of certain microorganisms. The following common intrinsic factors affect the growth and multiplication of microorganisms in foods.
Food preservation Prevention of the spoilage of food, which is achieved by a variety of techniques. These aim to prevent bacterial and fungal decay and contamination of food, which can cause food poisoning.
The comparison between different quick freezing techniques for fishery products is presented in Table10. The direct approach of aseptic packaging comprises of steam injunction and steam infusion. On the other hand, indirect approach of aseptic packaging includes exchanging heat through plate heat exchanger, scrapped surface heat exchanger, and tubular heat exchanger . Steam injection is one of the fastest methods of heating and often removes volatile substances from some food products. On the contrary, steam infusion offers higher control over processing conditions than steam injection and minimizes the risk of overheating products. Tubular heat exchangers are adopted for operations at higher pressures and flow rates.
Safety and Side Effects
Therefore, quality level of the raw materials prior to freezing is the major consideration for successful freezing. Washing and cutting generally results in losses when applied after thawing. Thus, fruits should be prepared prior to the freezing process in terms of peeling, slicing or cutting. Freezing preservation does not require specific unit operations for cleaning, rinsing, sorting, peeling, and cutting of fruits . Shape and size of the container are also important factors in freezing products.