The present invention relates to new methods and uses for the qualitative and quantitative detection of microbial nucleic acids using at least a first control nucleic acid, or a first and a second control nucleic acid in different concentrations. Therefore, the weak detected signal obtained by detecting reflected and scattered light from small foreign matters and defects is buried in the electric noise, which has been an obstacle in detecting small foreign matters and defects. 008 gsm and not greater than about 5 gsm, and the nonwoven fabric or component has a basis weight of at least about 8 gsm and not greater than about 40 gsm, a pore size of less than or equal to about 27 microns when measured at 10% of cumulative filter flow. The reflected wave signal includes components other than the transmitted carrier wave signal if the sensor senses a vibration event. The cage is disposed at least partially in the housing cavity.