Investigation of the Optical Clarity and Transmittance of Polythene Bags Used in Nigerian Food Markets

Polythene bags are the dominant food packaging material in Nigerian markets, used for fresh produce, liquids, and dry goods. Their optical clarity and light transmittance determine the visibility of food contents, which influences consumer purchasing decisions and may affect light-sensitive food quality during storage. This study investigates the optical clarity and spectral transmittance of polythene bag samples collected from Wuse Market in Abuja and from Bodija Market in Ibadan. Samples include low-density polyethylene bags of varying thicknesses from 25 to 80 micrometres. Spectral transmittance is measured from 350 to 800 nm using a UV-Vis spectrophotometer fitted with an integrating sphere to capture total transmittance including diffuse components. Haze and clarity are determined following ASTM D1003 procedures. Results indicate photopic transmittance values of 64 to 88 percent across the sample thickness range. Haze values increase from 3.2 to 18.7 percent as thickness increases, reflecting greater internal scattering in thicker films. UV transmittance below 380 nm exceeds 60 percent in all samples, indicating no inherent UV protection for light-sensitive food contents. The study recommends labelling requirements for light transmission performance of food packaging polythene in Nigeria's consumer protection standards. Keywords: polythene, optical transmittance, food packaging, haze, UV transparency