Food preservation by using irradiation

What is food Irradiation?

Food preservation by irradiation is a method in which the food is exposed to ionizing radiation like, gamma rays, electron beams or x-rays etc to prevent from microorganisms or bacterial infection is known as food Irradiation.

Based on intensive analysis, it’s been recommended by the Joint expert Committee on quality of Irradiated Foods that “any food irradiated to a mean dose of 1 Mrad (10 kGy)  is called irradiation.


Why Irradiation used in food preservation: –

Because the following reasons the irradiation method are used for preservation of food

a. Destruction of pathogenic bacterium and parasites of public health significance in raw and minimally processed foods;

b. Microbe removal of spices and dried vegetable seasonings;

c. Insect disinfestations of grains and different keep products;

d. Due to irradiation Inhibition of sprouting in bulb, tuber and root crops;

e.Time period extension of fruits and vegetables by dela, weight unit maturations, ripening and microbial spoilage;

f. Management of insect pests in recent fruits and vegetables for quarantine purposes;

g. Improvement of the refrigerated time period of meat, poultry, food and recent fruit and vegetables by reduction of spoilage inflicting microorganisms.

A unique advantage of using ionized radiations lies in their strong penetrating power. Materials to be treated are often exposed to radiations in their final packaging. So avoiding any potential risk of recontamination. The irradiated food should be ready, processed and transported hygienically.

As a results of the clearance and suggestions by the Codex Alimentarius Commission, over 40 countries have approved the utilization of food irradiation for one or additional food or food teams and over thirty countries are using it for industrial functions. 

Types of Irradiations methods used in food preservation

Food preservation by using irradiation

Now a day there are three methods of irradiations used in food preservation, that is : electron beams, or x-raysgamma rays (from cobalt-60 sources), electron beams, or x-rays. All of these three methods work the same way for preservation of foods.

No temperature requirement food processing or food preserving technologies, like as gamma rays, X-ray and electron-beam irradiation, this method’s used to eliminate microorganisms or pathogens in fresh raw foods, so it requires pasteurize delicate food products such as fresh produce, and perform phytosanitary treatment.

What is the principal of food irradiation?

So in the food Preservation using irradiation method, th e food is  ionizing by usinng radiations, electricity, x-rays and gamma rays to destroy bacterial or microorganisms, like as bacteria, viruses or insects in food. Food Irradiation also helps in delays ripening, improves rehydration, increases juice yield and inhibits sprouting, which helps preserve foods.

Commercial applications of irradiation in food preservation

1) Sprout Inhibition used for food preservation

Coordinated research has established the technological feasibility of preservation by using irradiation for sprout inhibition in potatoes, onions and garlic.

The use of radiations at levels of 30 to 150 Gy (0.003 to 0.015 Mrad) or less inhibits sprouting in tubers and bulbs, thereby extending their storage life. Government of India permits 30 to 90 Gy for irradiating onions and 60 to 100 Gy for potatoes.

2) Insect disinfestation

Food preservation by using irradiation

Several fresh produce (citrus fruits, mangoes, lentils), dried fish and spices are often infested with insect eggs, larvae or adult insects. At present most consignments are fumigated.

Owing to suspected toxicity problems, use of some fumigants like ethylene oxide and ethylene dibromide has been prohibited or restricted in some countries for the treatment of spices. Disinfection by irradiation is an effective alternate to fumigation.

It is a continuous process and requires a relatively short Disinfestation by irradiation is an effective alternate to. period of treatment. Since irradiation also increases shelf life of fruits and vegetables by delaying ripening, the marketing period of these foods is also extended by 2 to 5 days.

A dose of 0.2 kGy (0.02 Mrad) is sufficient to destroy insect eggs, larvae and render the insects themselves. incapable of further reproduction. In dried and smoked fish, about 2 kGy is required to kill 99 per cent larvae, although lower dose (0.2 KGy) will prevent the larvae of all fly species from developing into adults.

3) Radiation pasteurization used for

a. Reduce microbial population in spices and dry ingredients. This treatment is technically termed as radurization radiation pasteurization designed to kill or inactivate food spoilage organisms.
b. Kill or render harmless all disease-causing organisms (except viruses and spore-forming organisms) – a treatment technically called radicidation.


Radurization

When fruits, vegetables and meat are destined for cold storage, it is desirable to have minimum number of microbial cells on their surface. Ionising radiations at a dose of 0.2 kGy to fruits and 3 to 5 kGy to meat can be applied to disinfect their surfaces and extend their life during cold storage.

Similarly, spices, which carry heavy’ contamination of microorganisms on their surfaces, can be successfully decontaminated by the application of 4 to 5 kGy (0.4 to, 0.5 Mrad) of radiation without adversely affecting the volatile constituents of the product.

This treatment is considered superior to the use of chemical fumigation that leaves toxic residues. Moreover, the shelf life of fruits like strawberries and fresh fish can also be extended by radurization.

Radicidation

Food can also be made safe for human consumption by the application of irradiation in the process called radicidation. Low doses of irradiation (below 10 kGy) are helpful in the destruction of parasites and food poisoning bacteria in meat and poultry. 

Destruction of parasites such as Trichinella spiralis and Taenia saginata is achieved at a dose of 0.1 to 0.3 kGy, while doses of up to about 5 kGy (0.5 Mrad) are necessary to kill non-sporing pathogenic bacteria like Salmonella, Vibrio parahaemolyticus, Staphylococcus aureus and others.

Frozen meat, poultry, eggs and other foods liable to contamination with pathogens can be given irradiation treatment of below 10 kGy (1 Mrad) to destroy the pathogens. Radiation pasteurised foods (radicidized or radurized) like the heat pasteurised, must be stored under refrigeration.

Radiation sterilization – Radappertization

Food preservation by using irradiation

Irradiation is largely being used to sterilize medical devices and supplies. This requires a dose of 100 kGy (10 Mrad) or higher. If applied to foods, it will be highly damaging to its quality.

Therefore, similar to commercial sterilization, radiation treatments can be given to food to destroy all pathogens, most food spoilage organisms, as well as the spores of Clostridium botulinum.

Such a treatment is termed as radappertization and the resulting food can be stored at room temperature, in the same manner as thermally processed food.

Food designated for radappertization is blanched, pre-packaged and sealed under high vacuum to remove oxygen.

This is then frozen to -40°C and irradiated to a dose of about 10 to 50 kGy (1 to 5 Mrad) while in frozen state. The freezing step acts to minimize the possibility of nutrient loss or flavour changes during irradiation.

After irradiation, the treated food is allowed to thaw in the package and stored without refrigeration, as are heat processed foods.

A dose of up to 10 kGy has been found to present no toxicological hazards. The radappertized foods present no health hazards. However, when irradiation is used as an adjuvant to heat for commercial sterilization, it augments the sterilising efficiency of heat and does not have adverse effects on the food material.

Most research conducted in this direction has been limited to a few foods: meat, poultry, fish and some vegetables. Dairy products have been found unsuitable for radappertization, since undesirable flavour changes occur in the irradiated product.

Radiation sterilized foods have been enjoyed by the American astronauts and some hospital patients, such as organ transplant recipients, who are confined to special sterile environment.

Delayed Ripening


The ripening process in fruits such as bananas, tomatoes, pears, mangoes, guavas and others can be delayed by low dose irradiation (250 to 350. Gy). Also, the shelf life of fresh mushrooms can be extended by an irradiation treatment, which will prevent the growth of stem and opening of the caps.

If this is combined with proper packaging and storage temperature, the shelf life can be doubled. irradiation treatment. This application can also be used to bring about desirable chemical changes in certain food products. For example, a dose of 10 to 20 kGy (1 to 2 Mrad) of irradiation hastens the ageing process in alcoholic beverages.

Similarly, the odour in essential oils may be enhanced by treatment with a dose of 10 kGy (1 Mrad) of irradiation. In case of dehydrated vegetables, the time required for rehydration may be reduced by a dose of 2.5 to 25 kGy.

EFFECT OF IRRADIATION ON FOODS

Food preservation by using irradiation


Irradiation can cause a variety of changes in living cells. Low doses can interfere with cell division and alter the biochemical reactions involved in the ripening of fruits. High doses can kill the cells, thereby destroying microorganisms and insects. 

The chemical changes brought about by irradiation treatment depend upon the food to be exposed, the type of packaging, and processing conditions such as temperature during irradiation and storage time. 

However, based on extensive research, it has been established that many of the substances produced by irradiation and identified through the use of sensitive analytical techniques are familiar ones that exit in non-irradiated foods. These are also formed as a result of conventional processing such as boiling, frying and grilling.

A few new substances called radiolytic products may be formed. The United States Food and Drug Administration has estimated that the total amount of undetected radiolytic products that might be formed when food is irradiated at a dose of 1 kGy would be less than 3 mg per kg of food or less than 3 ppm.

lonising radiations are capable of initiating different changes in food systems and formation of certain chemically active substances.

The treated food is not heated and, therefore, shelf-stable products are produced that are closer to the fresh state in texture, flavour and colour. The food retains its freshness and physical state.

Effect on Water


When ionising radiations strike the water molecule, the molecule is split – technically called ‘radiolyzed’. Several intermediate compounds such as `excited water’, ‘free radicals of hydrogen and hydroxyl’, ionised water molecules’ and `hydrated electrons’ result.

When these intermediates react with one another and with other components of the food system in the presence of air, they produce hydrogen gas (₂), hydrogen peroxide (H₂O₂), hydronium ion (H₂O) and hydroxyl ions (OH) in addition to water itself. Most food components are capable of reacting

With the intermediates or end products of water radiolysis. The final complexes resulting from such reactions may bring about changes that affect colour, odour, taste or quality of the food material. There is no evidence that any of these compounds is dangerous for consumption.

Effect on Carbohydrates


In carbohydrates, oxidation as well as condensation reactions similar to non-enzymatic browning predominate. It has been suggested that some products of irradiation of sucrose may have toxic effects on cells. In the carbohydrates Starch and pectin are very sensitive to radiation. 


Effect on Proteins

In proteins the terms deamination, oxidation, polymerisation, and decarboxylation have been observed during irradiation. Histidine, phenylalanine, thyroxine and sulphur-containing amino acids are reported to be most sensitive to the effect of irradiation.

Effect on Lipids

Many reactions result in lipids, which are similar to oxidative rancidity. Several carbonyl (>C=0) containing compounds may be formed. The production of carbonyls and other potentially dangerous substances have led to the vast testing of irradiated foods for possible health hazards.

Effect on Vitamins

Since no cooking or heating is involved in pasteurising’ or sterilizing’ doses of irradiation, the food remains in `fresh’ state. The losses are generally less if oxygen is excluded and if the temperature during irradiation is low.

Vitamins A. E. C. K and B-1 in foods are relatively sensitive to radiation, while riboflavin, niacin and vitamin D are much more stable. Vitamin losses caused by irradiation are comparable to, or often less than, those produced by other processes used to achieve the same goal.

Following are the examples of food preservation by using irradiation

• Beef and Pork.

• Crustaceans (e.g.,shrimp, lobster and crab) Fresh Fruits and Vegetables.
• Poultry.
• Lettuce and Spinach.
• Seeds for Sprouting (e.g., for alfalfa sprouts)
• whole flour
• Food extracts .

Other examples : The following foods are irradiated foods potatoes, onions, garlic, some cereals, flour, whole flour, strawberries, mangoes, dried vegetables, powdered eggs, food extracts, paprika. In line with some estimates, as of 1999, total irradiated food processed worldwide stood at 243,000 metric tones.

Advantages of Food preservation using Irradiation

a. Destruction of pathogenic bacterium and parasites of public health significance in raw and minimally processed foods;

b. Microbe removal of spices and dried vegetable seasonings;

c. Insect disinfestations of grains and different keep products;

d. Due to irradiation Inhibition of sprouting in bulb, tuber and root crops;

e.Time period extension of fruits and vegetables by dela, weight unit maturations, ripening and microbial spoilage;

f. Management of insect pests in recent fruits and vegetables for quarantine purposes;

g. Improvement of the refrigerated time period of meat, poultry, food and recent fruit and vegetables by reduction of spoilage inflicting microorganisms.

Food Irradiation processing does not affect directly on flavour, nutritional value, texture and appearance of food.

Disadvantages of Food preservation using Irradiation

• Food Irradiation processing does not make a bad flavoured or spoiled food look good.
• It may or may not kill all bacteria on fresh food.
• So Food can be more harmful – present in the environment where the food are being treated by irradiation could expose humans cells to damage and mutation changes occurred.

• This food preservation using irradiation method also helps to preserve food for long time

What are Negative effects of irradiated food

Scientists also prove that the irradiation method forms volatile toxic chemicals present such as toluene, benzene and chemicals known, or suspected, to cause cancer symptoms and problems in birth defects.

Irradiation processing also Hazzard stunted growth in lab animals fed irradiated foods.

Does irradiation destroy nutrients in food?

Food Irradiation process is uses to preservation does not really make foods radioactive, compromise to food nutritional quality, or noticeably change the aroma, taste, texture, or appearance of food material. In fact that, any changes made by food irradiation are so it is minimal that it is not easy to tell if a food has been irradiate.

Is irradiation in food safe to eat?

Are irradiated foods safe? Yes absolutely safe, irradiated foods are safe. Irradiation processing makes meat and poultry like products safer by reducing the huge numbers of harmful bacteria and parasites. Food irradiation processing does not make foods radioactive in nature.

Conclusion :

I hope you may get all the information concerning about Food preservation by using irradiation method. When reading my article. After this, if you got any doubt then i will be able to help you tell me the comments section.

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