Browsing by Author "Ranpatabendi, T."

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    Determination of Minimum Food Preservative Combination Levels for Fruit Juices
    (Uva Wellassa University of Sri Lanka, 2013) Ranpatabendi, T.; Chandrasena, G.; Padmapriya, M.W.J.
    Higher levels of food additives than the maximum permitted levels are used by the food manufactures. According to Sri Lankan Food Act, These permitted levels of food additives are higher than the international standards (reference). Especially, in fruit juice manufacturing high levels of food preservatives are used. Different studies have shown that higher levels of food preservatives may cause health hazard such as gastric irritation, allergic conditions, asthma conditions and long term consumption may lead to cancers and genetic disorders in babies (Freedman, 1980). Developed countries are more concerned about the residual effect of food additives. Due to the fact that the residual level of food preservatives of Sri Lankan products is higher than the international standard, those products are failed at the export market. This study was conducted to find out the minimum levels of preservative combinations that minimize the risk to human health with respect to fruit juice preservation. Methodology The study was carried out at Microbiological Division of the Research and Development Department, Expolanka (Pvt) Limited. Two experiments were conducted during this study. Experiment I was conducted to evaluate the minimum inhibitory concentrations of food preservatives for selected microorganisms. Series of different concentrations of Sodium metabisulphite, Potassium sorbate and Potassium benzoate solutions were produced and pH was adjusted to 3.3. All the prepared preservative solutions were filter sterilized. Disk diffusion method was used to investigate the minimum inhibitory concentration of above preservatives and Saccharomyces spp. Minimum inhibitory concentrations of three preservatives were defined for the tested microorganisms. In second Experiment, the effectiveness of these minimum inhibitory concentrations of preservatives in preservation of fruit juices was determined. Mango, wood apple, mix fruit, lime and guava juices were used to meet the fruit juice specification given in the food act and SLSI guideline. Two preservative combinations were used by combining minimum inhibitory concentrations of preservatives. Sodium metabisulphite (SMS) with potassium sorbate (PS) and Sodium metabisulphite with potassium benzoate (PB) were combined and these combinations were assigned to all the fruit juice samples. Combination 01: Sodium metabisulphite 25 ppm + Potassium Sorbate 150 ppm Combination 02: Sodium metabisulphite 25 ppm + Potassium Benzoate 60 ppm All the samples were incubated at 25 C for 14 days as per the food act. Total plate count and yeast and mould (Y/M) were enumerated using the standard method as described by the Sri Lanka Standard Institution (SLS 516 part 2). The data obtained in the present study was statistically analyzed with analysis of variance (ANOVA) using Minitab 16 statistical package. Pair wise comparisons were done by tukey at 5% significance level.
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    Development of Rapid Dye Reduction (Resazurin) Test for Determination of Microbiological Quality of Coconut (Cocos nucifera) Water
    (Uva Wellassa University of Sri Lanka, 2019) Rangala, R.D.A.; Ranpatabendi, T.; Perera, G.A.A.R.; De Silva, P.D.P.M.
    Traditional microbiological testing methods are labor-intensive and time-consuming. Rapid microbiological tests are very important in manufacturing establishments where quick decisions are required to be taken. Resazurin test is widely used as a rapid and easy method of determining the microbiological quality of milk. The aim of this study was to investigate the applicability of resazurin dye reduction test as a rapid test method to determine the microbiological quality of coconut (Cocos nucifera) water in a coconut water bottling plants. Fifty-five coconut water samples obtained from desiccated coconut mills were subjected to dye reduction test along with the total colony count by standard pour plate method. Samples represented microbial counts ranged from 5.8×105 to 2.65×107 CFU/mL and reduction times range from 3 min to 115 min. A correlation was established between resazurin dye reduction times (min) and the colony forming units per milliliter of coconut water samples. A strong correlation (-0.989) between variables was detected. Regression equation established between dye reduction time and total colony count was applied to predict the microbial quality of coconut water samples. A specific colour chart was developed by using standard colour codes to identify the initial colour and the end colour of the resazurin reduction test. Thus, it can be concluded that the resazurin rapid dye reduction test can be used to identify microbial quality of coconut water within shorter period of time.