Chlorine dioxide gas may modify properties of polymeric packaging materials.Chlorine dioxide ([ClO.sub.2]), with its high oxidizing capacity and broad disinfecting property, finds use frequently as a disinfectant. As a biocide in foods, it has a microbial inactivating capacity against many important pathogenic and spoilage spoilage
decomposition; said of meat, milk, animal feeds especially ensilage. microorganisms that are located on the surface of products.
[ClO.sub.2], in its gaseous form, has been used for vapor-phase decontamination, both in treating the produce before packaging and sanitizing products inside packages. Little is known about its effects on packaging system material properties and performance.
Research at Michigan State University Michigan State University, at East Lansing; land-grant and state supported; coeducational; chartered 1855. It opened in 1857 as Michigan Agricultural College, the first state agricultural college. and elsewhere indicates that changes in the performance of certain polymers, when they're used as packaging materials, could impact a product's shelf life. This research could provide the information needed for selecting materials when [ClO.sub.2] gas is being considered for inclusion in a packaging system as a bactericide bac·te·ri·cide or bac·te·ri·o·cide
An agent that destroys bacteria.
bac·teri·cid that would improve the safety of fresh produce safety and prolong its shelf life.
In their research on the mass transfer of [ClO.sub.2], investigators determined the permeability, solubility and diffusion coefficients of [ClO.sub.2] for 10 types of polymeric packaging materials. Their approach involved using an isostatic i·sos·ta·sy
Equilibrium in the earth's crust such that the forces tending to elevate landmasses balance the forces tending to depress landmasses. technique. They used a continuous system that measured [ClO.sub.2] concentrations with an electrochemical sensor as a detector.
This effort showed that polyethylene terephthalate, polylactic acid, polypropylene, nylon, and multilayers of ethylene vinyl acetate and ethylene vinyl alcohol have high [ClO.sub.2] barriers. But polystyrene, linear low-density polyethylene, linear low-density polyethylene, high-density polyethylene and polyvinyl chloride demonstrated poor barrier characteristics to [ClO.sub.2].
The effects of gaseous [ClO.sub.2] on the physical and mechanical properties of polymeric packaging materials were also determined by exposing the selected materials to [ClO.sub.2] for one, seven and 14 days. Changes were observed, such as a significant decrease in the tensile strength and modulus of elasticity modulus of elasticity
The ratio of the stress applied to a body to the strain that results in the body in response to it. The modulus of elasticity of a material is a measure of its stiffness and for most materials remains constant over a range of stress. of the treated polyethylene samples. It also appears that changes occurred in the absorbance intensity of the infrared spectrum of polystyrene, polyethylene terephthalate, polylactic acid, and layers of ethylene vinyl acetate and ethylene vinyl alcohol, indicating that alterations occurred in the materials and their properties.
Further information. Rafael Auras, School of Packaging, Michigan State University, East Lansing, MI 48824; phone: 517-432-3254; fax: 517-353-8999; email: email@example.com.