Sample collection in microbiology: take a representative part of samples from a large number of analysis objects as analysis materials, which is called sampling.
Sample collection in microbiology is an important part of food analysis. The ingredients and contents of the same kind of food products or raw materials may vary greatly due to the different origin, maturity, processing and preservation conditions. The composition and content of different parts of the same analysis object may also be quite different.
It is necessary to evenly collect representative samples from a large number of tested substances with uneven composition and inconsistent composition, so as to prevent the components from escaping and being polluted. Otherwise, even if the later detection links are very precise and accurate, the test results are of no value.
Principle of correct sampling:
① The samples collected shall be uniform and representative, which can reflect the composition, quality and sanitation of all the tested foods.
② During the sampling process, try to keep the original physical and chemical indexes to prevent the components from escaping or bringing in impurities.
③ Steps of sampling
Test sample → original sample → average sample
Test sample: a small amount of materials collected from various parts of a large number of materials in the analysis object.
Original sample: many test samples together are called original samples.
Average sample: the sample from which a part of the original sample is taken for analysis and inspection after technical treatment