Reuse potential of clay pots for packaging of curd

Abstract

A Buffalo curd packed in a clay pot is one of the most traditional dairy products in Sri Lanka. Although both clay pots and plastic cups are used for packaging of curd, the clay pot is the most popular package. However, the clay pot is disposable and become a waste after a use. This unsustainable consumption of limited clay resource is not environment friendly and cost effective. Re-using clay pots after re-firing will protect the earth while enhancing profit to the curd producer. Therefore, the main objective of this study was to evaluate the effect of re-firing of used curd packing clay pots on physical & microbiological qualities, quality of curd and analyze the possible energy saving. A Completely Randomized Design (CRD) was used for the experiment with four treatments and eight replicates. The treatments are; Re-firing of used pots only once, twice, thrice and the control (new pots). Pots were re-fired at 800 0C for one hour using a muffle furnace. Then the physical properties: weight, colour and compressive strength were measured. The initial microbial loads were tested by plate counts. Mold growth on curd was visually observed and pH was also measured to evaluate the shelf life of curd. According to the results, re-firing improved the red colour while reducing initial microbial counts. There was no effect on compressive strength and pot weight. The porosity of pots increased with re-firing. This led to excessive water loss resulting pH reduction of curd after third firing. Mold growth on curd was not observed for 12 days. Therefore, pots can be re-used at least twice after proper re-firing and there by 34% of total energy and 2/3rd of clay resources can be saved in the curd industry.