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Growth of moulds inoculated into commercial mineral water
H Fujikawa1, J Aketagawa, M Nakazato
1Department of Microbiology, Tokyo Metropolitan Research Laboratory of Public Health, Japan. fujik@tokyo-eiken.go.jp
Abstract:
The growth of mould spores of Penicillium sp. and Cladosporium sp. inoculated in a commercial mineral water product was studied. The strains had been isolated as fungal foreign bodies in commercial mineral waters. In product A, which was not originally sterilized and was contaminated with psychrophilic bacteria, the inoculated mould spores of the strains did not grow; no increases in viable colony counts or beta-glucans concentration in the samples were observed during storage. In a sterilized product A, inoculated spores of the strains grew into visible foreign bodies. The viable colony counts and the beta-glucans concentration in the samples increased during storage. These results showed that in a sterilized mineral water product, mould spores could grow into visible foreign bodies.
Insights
Mould spores can grow in sterilized mineral water, forming visible foreign bodies. Unsterilized water contaminated with bacteria prevented mould growth, indicating sterilization is key for preventing spoilage.
Area of Science:
- Food Science
- Microbiology
- Water Quality
Background:
- Fungal contamination, specifically Penicillium sp. and Cladosporium sp., can occur in commercial mineral water.
- These fungi have been identified as foreign bodies in previously reported mineral water products.
- Understanding mould growth dynamics is crucial for maintaining mineral water safety and quality.
Purpose of the Study:
- To investigate the growth potential of Penicillium sp. and Cladosporium sp. spores in a commercial mineral water product.
- To determine the influence of sterilization and bacterial contamination on mould growth in mineral water.
Main Methods:
- Inoculation of mineral water product A with Penicillium sp. and Cladosporium sp. spores.
- Comparison of mould growth in non-sterilized (bacterial contamination) versus sterilized mineral water.
- Monitoring of viable colony counts and beta-glucans concentration during storage.
Main Results:
- In non-sterilized mineral water with psychrophilic bacteria, inoculated mould spores did not grow.
- In sterilized mineral water, inoculated mould spores successfully grew into visible foreign bodies.
- Sterilized samples showed increased viable colony counts and beta-glucans concentration due to mould growth.
Conclusions:
- Sterilization is a critical factor enabling mould spore germination and growth in mineral water.
- Mould spores can proliferate in sterilized mineral water, leading to visible contamination and potential quality degradation.
- The presence of competing bacteria in non-sterilized water may inhibit mould growth.