Browsing by Author "Wickramanayaka, T.D.G."

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    A study on microbial contaminations, sources and preventive measures in salted butter production in a commercial dairy plant
    (Uva Wellassa University of Sri Lanka, 2015) Wickramanayaka, T.D.G.; Abeyrathne, E.D.N.S.
    Dairy fat spreads are milk products relatively rich in fat in the form of a spreadable emulsion principally of the type of water-in-milk fat that remains in solid phase at a temperature of 20 °C (Codex Standard for Dairy Fat Spreads, 2006). There are two kinds of butter as sweet cream and ripened-cream. Sweet cream butter may or may not contain salt (Fernandes, 2008). To overcome the high demand of butter, a reputed dairy company in Sri Lanka engages in manufacturing salted butter. However, finish product frequently contain high microbial load before releasing to the packing which leads to quick rancidity. Consequently, it has become a problem to the company to obtain a profit. Therefore, this research was carried out to assess microbiological quality at different production steps to determine the sources of microbial contamination in salted butter production. Methodology A preliminary study was carried out to identify possible sample collection points including swab sampling points during production process. Samples were collected from raw cream, before and after pasteurization, after aging, during churning, final product, and wash water of butter granules and the churner. Swab samples were collected from cream and aging vats, hands of permanent workers (randomly), and inside and outside of the churner. Time and temperature during storage of cream in the cream vat, pasteurization and aging were recorded. Sample collection procedure was repeated for every batch up to identification of the contamination points. Quality of samples was evaluated by performing microbiological tests (total colony count, Coliform and fecal Coliform). According to the test results, contamination points were identified and microbiological (E. coli, yeast, and moulds), chemical (free fatty acid level of the final products) and physical (foreign matter observed from naked eye) properties were further analyzed. Entire tests were conducted in triplicate according to the analytical testing procedure of company. Data were finally analyzed by mean value comparison using Microsoft Excel 2013. Further, analyzed data were compared with the standards (SLS 279:1988). Results and Discussion According to the preliminary analysis, raw cream was stored for 4-5 hours at 7-8 °C in a cream vat. Mean total colony count in raw cream of seven batches was ranged from 110×10 to 127×10 cfu/g and Coliform and fecal Coliform bacteria were detected in all samples tested. After pasteurization (95 °C, 20 minutes), mean total colony count of all samples were lower than 10 cfu ⁄g and after aging (5-7 °C, 12 hours) (Table 01). Coliform and fecal Coliform bacteria were detected in all samples tested however, after pasteurization and aging, Coliform and fecal Coliform bacteria were not detected in any of the samples.
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    A Study on Microbial Contaminations, Sources and Preventive Measures in Salted Butter Production
    (Uva Wellassa University of Sri Lanka, 2014) Wickramanayaka, T.D.G.
    A study was conducted to find out microbial contaminations, sources and preventive measures in salted butter production in MILCO at Colombo milk factory. Preliminary study was carried out to identify possible sample collection points including swab sampling points during production process. Samples were collected from raw cream, before and after the pasteurization, after aging, during churning, final product, wash water of butter granules and the inside and outside of churner. Swab samples were collected from cream, aging vats, permanent worker's hands, and churner inside and outside. Quality of samples were assessed using microbiological (total colony count, Coliform, fecal Coliform, E. coli, yeast and moulds), chemical (free fatty acid level of the final products) and physical (foreign matter observed from naked eye) properties. Entire tests were conducted according to the analytical testing procedure-MILCO with modifications. According to the preliminary analysis, five batches among seven were contaminated with the Coliform during churning. Further analysis of contamination point showed that, there was Coliform in the churner wash water, swabs of the churner inside (after washing) and butter granules during churning in three batches among four. To prevent the contamination, hot water and steam cleaning was implemented before the production. After hot water (70-75 °C, 15 minutes) and steam (80-85 °C, 5 minutes) cleaning, samples of wash water, swabs and butter granules were negative in Coliform. However mould count of one batch was beyond the standards. After implementation of hot water and steam, free fatty acid levels were reduced to the standard level. There were no any physical contaminants observed in all batches tested. Hence, the study can be concluded that, microbiological, and chemical quality of salted butter can be improved by using hot water (75-80 °C, 15 minutes) and followed with steam (80-85 °C, 5 minutes) cleaning of the churner, while maintaining the basic manufacturing steps. Key words: Salted butter, Microbial contaminations, Sources, Preventive measures