What is Target Capture?
Target capture is a highly specific sample preparation method to purify and concentrate only the target RNA of interest.
Why is it done?
During the transfer step, the enriched samples are placed in a lysis buffer to break open the bacterial cell and release nucleic acids (DNA and RNA). At this point the lysis tube also contains other cell components like cell organelles, lipids, denatured proteins, and specific food matrix related compounds like ions, fat, oils and phenols.
Some of these compounds (for example, calcium ions in milk, fat and collagen in beef, polysaccharides in produce) can interfere with the downstream steps of amplification and detection. In addition, the tube may also contain nucleic acids from other bacteria that may cross react and lead to false positives. For these reasons, it is a good idea to have a purification step prior to amplification of the target nucleic acid.