Marijuana Business Magazine July 2019

July 2019 | mjbizdaily.com 89 Lab Testing 8 Incubate Undiluted Samples Analysts aren’t yet done with Whirl-Pak bags containing the undiluted samples. They are needed for the second part of the biocontaminant test, which is for E. coli and salmonella. This part requires the samples to be stored in a separate incubator overnight. In most states with legalized cannabis, E. coli and salmonella must be less than 1 CFU per gram—in other words, absent in cannabis and cannabis- derived products. Overnight incubation gives the bacteria enough time to continually double its population until it is able to be detected by DNA- based testing methods. 9 Extract DNA from Samples After the Whirl-Pak bags are stored overnight, they’re removed from the temperature- controlled incubator. A laboratory analyst takes a second portion of the sample, or aliquot, from the bag and prepares it for DNA extraction by a Promega Maxwell instrument. The Maxwell is an automated DNA-purification system that is capable of consistently and reliably extracting DNA from complex samples. Some laboratories use a spin-column procedure or other manual processes for DNA extraction. Manual extraction is time-consuming and requires several steps. Laboratories can save time and money investing in technology such as the Maxwell Promega instrument, which can extract DNA from 48 samples in 35 minutes. Since the instrument automates the process, there’s also less risk of error, so the lab’s clients can rest assured their samples are being processed correctly. The DNA is extracted into an elution buffer that has a slightly basic pH to stabilize the DNA molecules and prevent their degradation.