Irradiation for Food Packaging – Process and Techniques

By: Pallavi Jaiswal *

Food PackagingThe term ‘food industries‘ covers a series of industrial activities directed at the processing, conversion, preparation, preservation and packaging of foodstuffs. The food industry today has become highly diversified, with manufacturing ranging from small, traditional, family run activities that are highly labour intensive, to large, capital-intensive and highly mechanized industrial processes.

The term food preservation refers to any one of a number of techniques used to prevent food from spoiling. It includes methods such as canning, pickling, drying and freeze-drying, irradiation, pasteurization, smoking, and the addition of chemical additives. Food preservation has become an increasingly important component of the food industry as fewer people eat foods produced by their own lands.

In 2015, the International Agency for Research on Cancer of the World Health Organization classified processed meat, i.e. meat that has undergone salting, curing, fermenting, and smoking, as “carcinogenic to humans”. Maintaining or creating nutritional value, texture and flavour is an important aspect of food preservation.

The evolution and continuous innovation to food preservation techniques over the years has been necessary for subsistence across the globe. Processes like drying and salting have evolved into more modern techniques such as irradiation and high pressure food preservation.

Food PackagingIncreasing the shelf life of food has many obvious benefits; a larger food supply leads to lower prices for consumers and perishable foods become more transportable, to name a few. New preservation technologies are not just working to increase longevity; they are also functioning to sustain the same qualities of the food that make it desirable in the first place. The physical characteristics and chemical composition of the food will no longer be compromised during the preservation process.

The U.S. Food and Drug Administration (FDA) allows the use of irradiation as a means for improving food safety and extending the shelf life of certain foods.

Foods are typically packaged in final form prior to being irradiated, thus reducing the likelihood that new pathogens will be introduced after the irradiation step. This means that the packaging materials are being exposed to the same irradiation source as the food itself. This article describes a brief of FDA’s regulations pertaining to packaging that are in contact with food during irradiation, the effects of irradiation on new food packaging materials, and the techniques.

The FDA has evaluated the safety of irradiated food for more than 30 years and has found the process to be safe. The World Health Organization (WHO), the Centres for Disease Control and Prevention (CDC) and the U.S. Department of Agriculture (USDA) have also endorsed the safety of irradiated food. National Aeronautics and Space Administration (NASA) astronauts eat food that has been sterilized by irradiation to avoid getting food borne illnesses when they fly in space. Over the years many food packaging materials have been approved for irradiation.

There are three sources of radiation approved for use: Gamma radiation (with Co-60 or Cesium-137 radioisotope), X-rays (high energy of up to 5 MeV) and Electron beam (high energy of up to 10 MeV).

These interactions result in the formation of energetic electrons at random throughout the matter, which cause the formation of energetic molecular ions. These ions may be subject to electron capture and dissociation, as well as rapid rearrangement through ion-molecule reactions, or they may dissociate with time depending on the complexity of the molecular ion. Effects of radiation on matter depend on the type of the radiation and its energy level, as well as the composition, physical state, temperature and the atmospheric environment of the absorbing material.

The chemical changes in matter can occur via primary radiolysis effects, which occur as a result of the adsorption of the energy by the absorbing matter, or via secondary effects, which occur as a result of the high reactivity of the free radicals and excited ions produced as a result of the primary effects.

These highly reactive intermediates can undergo a variety of reactions leading to stable chemical products. In general, it is these chemical products that are detected and referred to as radiolysis products. For living things, these chemical changes can ultimately have biological consequences in the case where the target materials include living organisms. In the U.S., components of packaging used to hold food during irradiation must undergo premarket approval by the FDA and may be used only if they comply with the regulations in 21 CFR 179.45 or are the subject of an effective food contact notification or Threshold of Regulation exemption.

Irradiation does not make foods radioactive, compromise nutritional quality, or noticeably change the taste, texture, or appearance of food. In fact, any changes made by irradiation are so minimal that it is not easy to tell if a food has been irradiated. The FDA is responsible for regulating the sources of radiation that are used to irradiate food and approves a source of radiation for use on foods only after it has determined that irradiating the food is safe. Irradiation can cause changes to a packaging material that might affect its integrity and functionality as a barrier to chemical or microbial contamination.

Conclusion

Improved microbiological safety of food may be attained by using irradiation in the production of several types of raw or minimally processed foods such as poultry, meat and meat products, fish, seafood, fruits, and vegetables. When food or any packing material is exposed to a carefully measured amount of intense ionizing radiation, the radiation energy breaks the bonds in the DNA molecules of microorganism, thus the organisms die or become unable to reproduce. In fact, following the recent outbreaks of food borne pathogens in fresh produce, there has been increased interest in using irradiation for improving the safety of fresh produce. However, food manufacturers must ensure that both the irradiated food and packaging materials used during the irradiation process are authorized for the proposed use.


* Project Leader (Assistant manager); R&D- Tropilite Foods Pvt. Ltd.

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Food Marketing & Technology is a monthly magazine published by L.B. Associates Pvt Ltd

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