Abstract:
Soft drinks are simply defined as any non-alcoholic beverage containing syrups,
essence or fruit concentrates that are mixed with water or carbonated water. Basic raw
materials of carbonated soft drinks are purified water, sweeteners, carbon dioxide,
permitted colours and flavours, acidulants, emulsions, heading agents, preservatives
(SLS, 183:1997). These are not consumed for their food value, but rather for their
thirst quenching properties or for their stimulating effect.
Soft drinks are more susceptible to microbial spoilage than other food products, due to
both intrinsic and extrinsic factors. Microbial spoilage occurs due to three different
kinds of microorganisms yeasts, moulds and bacteria (Vamnum, 1994). Yeasts are the
dominant spoilage organisms in soft drinks. Spoilage pattern typically involve film
formation, fermentation with gas production, turbidity and sediments and ‘fruity’
flavours. Mould spoilage involves visible growth together with bitter flavour and
discoloration.
The study involves the identification of places that are highly vulnerable to
contamination by yeasts and moulds. Pour plate method, 3M Petrifilm, swabs
testing were used to count the yeasts and moulds. Mouthpiece o f filler, Production
environment, and stock syrup filter showed high count o f yeasts and moulds."
Genus Aspergillus was isolated in the production environment by using streak method
and confirms it by using slide culture technique. Concentration o f Benzioc acid, a
preservative for yeasts and moulds, measured by HPLC method was comparable with
Sri Lanka standard (160 ppm).
Yeasts and moulds present in mouthpieces were studied for their tolerance by using a
rinse with different concentration of chlorine solutions (175, 250, 400, and 500) ppm
and the effectiveness was measured by using swab testing and finished product
testing. Results showed that no yeast and moulds count was observed after washing
with 400 ppm and higher chlorine solutions. According to the results analyzed by one
way ANOVA, yeast and mould counts were nil in 1ml o f finished product o f Soda
after the proposed pretreatment of mouth pieces (p=0.011<0.05).
