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A tube assay for contamination caused by pectolytic aspergilli
Abstract:
Spoilage fungi of the genus Aspergillus were detected and estimated in 24 h by a modification of the Most Probable Number method. The method is based on the production of pectolytic enzymes in a medium supplemented with pectin. These enzymes hydrolyse the bonds of pectin to produce galacturonic acid, causing a fall in pH and an indicator present in the medium changes colour, thus allowing tubes to be scored as positive. Results obtained by this method were generally higher than those obtained by traditional plate counts.
Insights
A modified Most Probable Number method rapidly detects Aspergillus spoilage fungi in 24 hours. This enzyme-based technique provides higher fungal counts than traditional plate methods.
Area of Science:
- Food microbiology
- Enzymology
- Mycology
Background:
- Aspergillus species are common spoilage fungi in food products.
- Accurate and rapid detection of spoilage fungi is crucial for food safety and quality control.
- Traditional plate count methods for fungal enumeration can be time-consuming.
Purpose of the Study:
- To develop and validate a rapid method for detecting and quantifying spoilage fungi of the genus Aspergillus.
- To compare the efficiency of the new method with traditional plate count techniques.
Main Methods:
- A modified Most Probable Number (MPN) method was employed for fungal detection.
- The method utilizes the production of pectolytic enzymes by Aspergillus species in a pectin-supplemented medium.
- Detection is based on pH changes indicated by a colorimetric indicator.
Main Results:
- The modified MPN method successfully detected and estimated Aspergillus populations within 24 hours.
- Results from the modified MPN method were generally higher than those obtained by traditional plate counts.
- The enzyme-based detection system proved effective in identifying fungal presence.
Conclusions:
- The modified MPN method offers a rapid and sensitive approach for enumerating Aspergillus spoilage fungi.
- This technique provides more comprehensive results compared to conventional plate counts.
- The method has potential applications in food quality assessment and spoilage monitoring.