A tube assay for contamination caused by pectolytic aspergilli.
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.
D001230:Aspergillus / Q000201:enzymology / Q000302:isolation & purification*; D005516:Food Microbiology; D008828:Microbiological Techniques; D010368:Pectins / Q000378:metabolism*
D010368:Pectins