Irradiated meats

Obana, H., Eurata, M., and Tanaka, Y., Analysis of 2-aUcylcyclobutanones with accelerated solvent extraction to detect irradiated meat and fish, J. Agric. Food Chem., 53, 6603, 2005. 

Following the success of these collaborative trials, standard methodologies for the application of the EPR method for the identification of irradiated meat bones, fish bones and some fruits have been prepared and are about to be submitted to the European Committee of Normalization. At the time when these trials were carried out there was not sufficient information available to permit inclusion of Crustacea among the products being examined and thus validation of the method for the identification of these irradiated foods has to be undertaken. 

Desrosiers, M.F. (1992). EPR methods for food irradiation 1. Results of ADMIT co-trials on irradiated meat detection. Second Research Co-ordination Meeting, Hungary, 15-19 June, IAEA, Vienna, 62. 

The primary objective was to conduct a continuing investigation and to assemble facts relating to the analytical composition of volatile compounds produced in irradiated meat and of a number of model systems,... 

The procedures for irradiation, collection, and analysis of the volatile compounds have all been described (1, 2, 3, 5, 7, 9, 11). A cryogenically programmed gas chromatograph coupled to a rapid scanning mass spectrometer provided for the analysis of the volatile components isolated from several irradiated meats and lipid substances (6). These studies have now been extended to include other component substances in order to acquire still further understanding of the source of the irradiation-induced volatile compounds from among the various meat constituents. 

It is now well established (6,10) that the hydrocarbons, except possibly those having three or four carbon atoms, found in the irradiated meats can come only from the lipid. This hypothesis has been verified in earlier studies, when the volatiles from irradiated methyl oleate (10) were found to contain appreciable quantities of alkanes and alkenes, and now in more detail from studies of both triglycerides and fatty acid esters. 

Most of the other products found in irradiated meat volatiles except those containing sulfur or aromatic rings may also be accounted for by mechanisms associated with alkyl free radical formation in the fat. Oxygenated compounds are far less abundant than hydrocarbons, but appreciable amounts of a homologous series of n-aliphatic alcohols up to hexanol are found. Of these, only ethanol is detected in the unirradiated controls. Since the water content of meat averages nearly 60%, the formation of alcohols may be thought to occur by reaction of the alkyl free radical with water. Such a mechanism is supported by the fact that only traces of alcohols are found in irradiated dry butterfat and were undetected in irradiated triglycerides or methyl esters of fatty acids. 

Table III. Miscellaneous Compounds in Irradiated Meat Volatiles...

In meats, of course, there are components which arise from the protein which cannot be present in the products from pure fat. Table III shows some of the sulfur compounds and aromatic compounds which are also found in irradiated meats. Many of these can be postulated as arising from direct bond cleavage of amino acid moieties. Benzene and toluene may come from phenylalanine and phenol and p-cresol from tyrosine. Recent studies have been directed to considering the origin of some of the compounds from proteinaceous substances. Some of the sulfides, disulfides, and mercaptans can derive directly from cysteine or methionine, but those containing more than two carbon atoms in a chain require more than a superficial explanation. In order to evaluate the contribution of the volatiles from the protein as well as the lipid constituents of meat, volatile components produced in various protein substances have also been analyzed. 

GINGER, I. D., LEWIS, V. J. and SCHWEIGERT, B. s. (1955). Changes associated with irradiating meat and meat extracts with gamma rays. J. Agric. Food. Chem., 3, 156-159. 

TAPPER, A. L. (1956). Regeneration and stabihty of oxymyoglobin in some gamma irradiated meats. Food Res., 21, 650-655. 

To put into perspective the chemistry associated with radiation pasteurization and sterilization, the basic chemical processes occurring in the constituents of irradiated meat and poultry are considered. Major constituents include the aqueous phase, the muscle and pigment proteins, the lipid (or fat) phase, and the carbohydrates. Minor constituents include salts, vitamins, and nucleic acids. The implications for assessing the wholesomeness of irradiated products, for gaining additional regulatory approvals, and for optimizing product quality and functionality are also considered. 

Any possible risk in consuming irradiated meats or other irradiated foods would have to be associated with a significant formation of a radiolysis product with a potent chronic toxicity or genotoxicity potential. Based on the radiolytic... 

The radiolysis of food constituents leads to minor but sometimes perceptible changes in sensory qualities associated with the net formation or degradation of a specific constituent. Color, texture, and rancidity are qualities that can be affected either during irradiation or subsequent storage, depending on the food, the atmosphere, the packaging, and the irradiation dose and temperature. Often, there are implications in the radiation chemistry for ensuring optimal quality of irradiated meat products. 

Figure 19. Dependence of shear force on the accumulated dose for various irradiated meats. Symbols - corned beef - roast beef and - smoked turkey.

I.A. Taub et al., Chemiclearance Principle and application to irradiated meats, in Proceedings of the 26 European Meeting of Meat Research Workers, American Meat Science Association, Colorado Springs, Vol. One, 1980, pp. 233-236. 

C. Merritt, Jr. and LA. Taub, Commonality and predictability of radiol3nic products in irradiated meats, in P S. Elias and A.J. Cohen (eds.). Recent Advances in Food Irradiation, Elsevier, New York, 1983, pp. 25-57. 

K. M. Morehouse and I. A. Taub, Relationship of volatile hydrocarbons to lipids in irradiated meats, in Proceedings of International Conference on Future Nuclear Systems, American Nuclear Society, LaGrange, 1999, Paper No. 144. 

Du et al. (50-52) reported no differences in TBARS between irradiated and nonirradiated chicken breast fillets and chicken and turkey rolls. As dietary CLA increased, however, the TBARS values of chicken rolls decreased. This could be caused by the decreased unsaturated fatty acid content in meat after dietary CLA treatment (53). We have observed similar results in vacuum-packaged irradiated meats in that ready-to-eat (RTE) turkey rolls from birds fed CLA treatment had lower TBARS than did those fed the control diet. The main reason for the improved oxidative stability could be due to the decreased proportion of unsaturated fatty acids in meat caused by the dietary CLA (54). Irradiation had a significant influence on numerous volatiles, mainly sulfur compounds, aldehydes, and alkanes. Dimethyl sul-... 

FIG. 1-2 Dennis Olson conducts research using a Circe 3 linear accelerator to irradiate meat products at Iowa State University. (Source Keeping Food Germ Free. )... 

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