Contamination from the environment as a source of bottled water off-odour: a case study

Significance of the Topic

Growing demand for bottled spring water alongside strict quality standards makes detecting and eliminating odour defects crucial for consumer acceptance and brand integrity.

Objectives and Study Overview

This case study aimed to establish a methodology to pinpoint the source of an unexpected fatty off-odour in packaged spring water through combined sensory and analytical screening.

Methodology and Instrumentation

A two-tiered approach was applied:

• Sensory Screening: Triangular tests with trained panelists to confirm odour anomalies.
• Analytical Profiling: Headspace SPME coupled to GC/MS with olfactometry on an Agilent 7890B GC, 5977A MSD, DB-5MS column and olfactometric detector for non-target identification.
• Quantification: Selective ion monitoring (SIM) of identified compounds (n-nonanal, 2,4-decadienal) with external calibration in spiked water.
• Detection Thresholds: Determined by olfactometric and triangle test protocols.

Main Results and Discussion

Triangular tests indicated significant off-odour in two of three samples. GC-MS/O pinpointed 2,4-decadienal and n-nonanal as key aroma-active compounds described as greasy and fatty. Quantitative analysis revealed 2,4-decadienal levels from 0.88 to 3.13 µg/l, surpassing its 0.75–1 µg/l odour threshold, whereas n-nonanal remained below sensory impact levels. Packaging migration from frying-related lipid oxidation products under improper storage was identified as the contamination route.

Benefits and Practical Applications

• Rapid odour defect diagnosis using combined sensory and GC/MS-olfactometry.
• Tailored storage and material selection guidelines to prevent lipid oxidation product migration.
• Quality control protocols for early detection of off-odours in bottled beverages.

Future Trends and Possibilities

Advances in high-resolution olfactometric GC techniques and accelerated shelf-life simulations will enhance trace-level detection of odorants. Integration of real-time sensory sensor arrays and predictive modelling may streamline early warning systems in production and distribution.

Conclusion

The study demonstrates a robust workflow combining sensory trials, SPME-GC/MS/O screening, and targeted quantification to identify 2,4-decadienal as the off-odour source in bottled water. Proper packaging and storage management can mitigate such sensory defects.

Reference

• Hanková M., Kružík V., Čížková H., 2018. Contamination from the environment as a source of bottled water off-odour: a case study. Kvasny Prum, 64(4):185–188. DOI:10.18832/kp201821.