Effects of Environmental Conditions on Growth and Permanence of Pseudomonas aeruginosa in Bottled Water

Abstract

Pseudomonas aeruginosa is considered as a process quality management indicator. Its occurrence reveals an environmental pollution at either the water source or at bottling process area. The present paper aims to study the effects of environmental conditions on the growth and survival of this bacterium in bottled water. Initial bacterial load in samples before inoculation and subsequently at various intervals was measured by membrane filtration technique. Microbial suspensions containing Pseudomonas aeruginosa were prepared to inoculate at least 102 cfu/ml microorganisms in each bottle. Samples were stored at 4ºC, 20 ºC and 37 ºC,as well as outdoors in darkness and in sunlight for 0 (immediately after inoculation), 3, 7, 14, 28 and 50 days. Results demonstrated that bacterial population increased by the 3rd day in all of the conditions, and that samples stored at 37 ºC showed the highest increase. The most substantial reduction in the amount of bacteria was observed at 4 ºC and for the samples in sunlight, so that after 50 days it was as low as 0.1 of the initial amount. Room temperature seemed to have no noticeable effect after 50 days. It was shown that high temperatures could lead to an increase of Pseudomonas aeruginosa, while low temperatures and sunlight in cold weather could decrease its concentration

Keywords

• Pseudomonas aeruginosa, Bottled water, Storage, Environment, Light, Temperature