Impact of bottled water storage duration and location on bacteriological quality

Abstract

An investigation studying the effects of storage duration and location on the persistence of heterotrophic microorganisms in oligotrophic bottled water environments has been completed. One-gallon high-density polyethylene water containers stored for up to 16 weeks at temperatures ranging from 2°C to >49°C in a refrigerator, indoor cabinet, covered porch, and car trunk were evaluated for microbiological quality. Heterotrophic plate counts (HPCs) of up to 4 × 10³ cfu/mL were detected in containers stored on a porch and car trunk; whereas, HPCs were found not to exceed 400 cfu/mL and 100 cfu/mL for bottles stored in indoor cabinets and refrigerators, respectively. Containers stored on an enclosed porch for up to seven years contained HPC of up to 4 × 10⁴ cfu/mL. Logistic and Gompertz growth models predicted microbial growth rates for bottled water stored on a protected porch environment for long (R ² 0.99) and short-term (R ²0.86) durations.

Keywords:

• bottled water
• heterotrophic plate count
• microbiological growth
• water storage

Acknowledgments

The work conducted in this study was performed as part of the requirements of UCF's Burnett Honor's College Honors in the Major undergraduate program. The research was funded, in part, by UCF's Research Foundation through a grant provided by the Jones Edmunds Research Fund (Project RF1047820). Any opinions, findings, and conclusions expressed in this material are those of the authors and do not necessarily reflect the views of UCF (Orlando, FL), its Research Foundation or the Burnett Honor's College, nor of Jones Edmunds Associates, Inc. (Gainesville, FL). The contributions of Maria Pia Real-Robert, laboratory coordinator of UCF's Department of Civil, Environmental and Construction Engineering, are deeply appreciated.