Microbiological quality of water vending machines

Abstract

Consumption of water from vending machines has recently increased in the United States. However, studies describing the bacteriological quality of water from these machines are scarce. In this study, bacteriological analyses were performed on samples from 30 water vending machines (W VM s), three of which were sampled weekly for 3 weeks. Bacteriological analyses were also conducted on the nozzle dispensers and the drains of 15 WVMs. Heterotrophic bacteria, total and fecal coliforms, and Pseudomonas aeruginosa were enumerated. Physico-chemical parameters such as pH, temperature, turbidity and residual chlorine were also examined. P. aeruginosa was found in 23% of the water samples and coliform bacteria in 20%. Heterotrophic plate count (HPC) bacteria were found in all samples and 73% had numbers greater than 500 colony forming units (CFU) ml ±1 . The HPC bacteria ranged from 9 to 48 000 CFU per sampled area on the dispensing nozzle. Total coliforms and Escherichia coli were detected in the drain samples with HPC bacterial concentrations from 1000 to 56 000 CFU per sampled area. No significant correlations were found between the physico-chemical and bacteriological parameters.

Coliform contamination on faucet surface of water vending machines in Klang Valley

“…Despite cases of water vending machines contaminated by faecal coliforms (E. coli O157:H7) [50] , fortunately, none of the selected subjects in this study was found to harbour faecal coliform (Figure 1, Table 3). However, in accordance to other studies [51,52] ,the presence of other total coliform (eg. Klebsiella, Enterobacter or Citrobacter species) was reported in our findings.…”

Microbiological Quality of Drinking Water from Water Dispenser Machines

“…In total, 16 out of 49 samples which are 32% of the overall results detected total coliform. A quite similar study detected coliform bacteria in 20% of the drinking water samples from vending machines [5]. The microbial contamination can be mainly from soil/dust or due to the presence of some insects, but most of the bacteria belonging to the total coliform group do not cause serious health effects since they are considered harmless [8], [9].…”

“…The presence of this bacterium mainly indicates low nutrient environment, as it lives in soils, water, and hot or moisture environment [6]- [8]. It causes many side effects, especially to the immuno-compromised people who are already weak and responsible for the common outbreaks and infections such as respiratory system infections, urinary tract infections, and various types of systematic infections [5].…”

Sachet drinking water in Ghana's Accra-Tema metropolitan area: past, present, and future

“…Technology has allowed vended water to evolve even further in the developed world, and a recent body of literature highlights the challenges in maintaining quality control of machine-vended water (i.e. filling personal containers) in the US and Europe (McSwane et al 1994; Chaidez et al 1999; Hunter & Barrell 1999; Schillinger & Du Vall Knorr 2004). The vast majority of published literature on sachet water addresses product quality, and this section reviews that body of work.…”