Introduction: The high quality and saniety of ingredients as well as what we use daily are very important. The necessity of analysis the high and low density polyethylene (HDPE and LDPE) compositions as the premitive granoul and used disposable food containers lead us to start this research. The present study, therefore, aims to evaluate mutagenicity and carcinogenicity effect of the compositions.

Methods: The method is based on Ames test applying Salmonella typhimurium strains TA100, TA104 which received directly from Professor Ames. In the first stage, these strains for property purity of mutation were confirmed. Then, polyethylenes compositions have been added separately to minimal agar medium contain fresh overnight culture (TA100, TA104) and compared to positive control (index of mutagen sodium azide and bacteria) and negative control (index of distilled water and bacteria). In the other stage rat liver tissues microsmes produced under sterile conditions had been added separately to minimal agar medium with polyethylene compositions and it was measured the effect of the carcinogen material and bacteria status affected by reverse mutation and histidin produced.

Results: There was a specific mutation in the histidine synthesis gene that made these strains (TA100, TA104) become an external source of histidine for theirs growth. These strains upon exposure to an external mutagen undergo a reverse mutagenecity in theirs mutated histidine synthesis operon and these strains then can grow in a histidine free medium. In this research considering to colony numbers and comparison with negative control index containing several colonies produced by spontaneous mutation approved materials mutagenicity and compared. The result, also showed that the HDPE grades as the raw material and their products made in the forms of disposable glasses and containers, drinking bottles and milk bags don’t possess the mutagenicity property, but plastics bags made from LDPE caused reverse mutation of S.typhimurium of these products. If these products coated by liquid or solid oils were found to have much more affects on mutagenicity of the films.

Conclusion: Considering the above results, it seems that polyethylene is a safe element. The only reason, then for mutation or carcinogenicity of the PE thin bags is the presence of some very active elements added to polyethylene or involved in its formation. This critical case makes us have more care and control on the mechanism of plastics bags production.

Hakim Research Journal 2005 8(3) 45-53.