INFLUENCE OF STORAGE CONDITIONS ON SURVIVAL OF SELECTED BACTERIA IN BOTTLED MINERAL WATER

Blue Planet Earth

Blue Planet Earth

1,386,000,000 cubic km (332,500,000 cubic miles)ALL WATER on our planet: oceans, seas, ice caps, lakes and rivers, groundwater, atmospheric water, even water in you, your plants and pets.

2.5% of total volume is FRESH-WATER (that tiny sphere), of which:68.9% glaciers and permanent snow30.8% groundwater (soil moisture, swamp water permafrost )0.3% Lakes and Rivers (that tiny dot)

Pack it Sell it

What ARE you paying for?

Current regulations in Serbia: NO coliforms, faecal coliforms, faecal enterococci nor Pseudomonas aeruginosa in 250 mL Total count 10* CFU/mL

The Aim of Our Study

How does different storage conditions (temperature, light) effect the bacteria present in bottled natural mineral water CONTROL sample

How does the number of pathogens change in artificially contaminated water under the same storage conditions

Workflow

Materials and Method

Microorganisms for artificial contamination Citrobacter freundii, Escherichia coli, Enerococcus faecium, Pseudomonas aeruginosa (DensyCheck, pour plate)Control sample total count bacteria in original packages

Media for total count: PCA R2A (American Public Health Association, APHA)Membrane filtration: Citrobacter freundii, Escherichia coli - Chromocult Coliform Agar (CCA) Enerococcus faecium - Chromocult Enterococci Agar (CEA) Pseudomonas aeruginosa - Cetrimid Agar (CA)

Results

Preliminary testing of different brands of bottled natural mineral water

SampleTotal count (CFU/mL)Pseudomonas aeruginosaColiformsFaecal coliforms22 oC37 oCIndndndndndIIbbndndndndIIIndndndndnd

Results

Temperature profile in room during storage perioddaystemperature

Results

Results

days ResultsCitrobacter freundii

Results

Conclusion

All bottles of natural mineral water was in accordance with microbiological safety given in Regulations on the quality of quality and other requirements for natural mineral water, natural spring water and table water.

It was confirmed that use of low-nutritious media, such as R2A gives us more realistic results, when compared to high nutritious PCA, especially when it comes to presence of saprophytic, autochthonous bacteria from the water.

Pathogenic bacteria tend to die off at room temperature more rapidly than at refrigerator temperature, with the exception of P. aeruginosa, which even tend to multiply rapidly at room temperature.

When stored in refrigerator P. aeruginosa kept its initial number during period of 75 days, while other pathogens tend to decrease in number.

THANK YOU FOR YOUR ATTENTION

MSc Marina Rajirajich.marina@gmail.comDr Dragoljub CvetkoviDr Aleksandra VelianskiDr Sinia Markov

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*Workflow can be schematically presented in few steps. First of all, the selection of bottled water had to be made. The one that was picked out had the lowest number of culturable bacteria in initial time. That was in order to facilitate their monitoring during a period of storage at two different temperatures.

Next step was a selection of bacterial strains that will be used for the inoculation of bottles. Bacteria were isolated from the water like wild strains, and were identified and confirmed by Vitek 2 Compact System. In order to determine the behavior of selected bacteria recovery tests were conducted.

A total of 60 bottles of natural mineral water were inoculated with the following bacteria: Enterococcus faecium, Escherichia coli, Pseudomonas aeruginosa and Citrobacter freundii. Half of these bottles were stored at room temperature, and the other half in the fridge temperature.

Under the same conditions, 60 noninoculated bottles from the same batch were stored. At appropriate time intervals, samples were taken from both temperatures and membrane filtration was performed. Incubation was carried out on selective media for 24 - 48 hours at a temperature of 37 C, according to ISO standard.

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