A study on microbial contaminations, sources and preventive measures in salted butter production in a commercial dairy plant
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Date
2015
Journal Title
Journal ISSN
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Publisher
Uva Wellassa University of Sri Lanka
Abstract
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.
Description
Keywords
Animal Sciences, Animal Production Technology, Milk, Milk Production, Microbiology