The results of a Total Aerobic Count (TAC) test are an indication of bacterial contamination on a cannabis sample.
In the food industry, testing labs use TAC tests to gauge a manufacturer’s sanitary quality and adherence to good manufacturing practices. However, TAC tests are unable to differentiate between pathogenic, beneficial, and benign bacteria, making them poor indicators of safety. A low TAC result does not mean a cannabis sample is free of pathogens. A high TAC result doesn’t mean a sample it is harmful to consumers. This is especially true in cannabis, which has a diverse microbiome of beneficial microbes that are not harmful to humans. For example, many organic cannabis growers use Bacillus subtilis, an aerobic bacteria, as a fungicide.
Still, many cannabis regulators require cannabis samples pass TAC testing before they can be sold in dispensaries. The most current version of the Cannabis Inflorescence and Leaf monograph published by the American Herbal Pharmacopoeia, which many states use to determine pass or fail criteria for microbial testing, recommends less than 100,000 CFU/g on cannabis plant material and 10,000 CFU/g on extracts.
Peer-reviewed studies have shown that qPCR testing methods, such as the PathoSEEK Microbial Safety Testing Platform, are able to more accurately detect and quantify bacteria species present on a cannabis sample than culture-based methods. The PathoSEEK Total Aerobic Count test looks for a specific DNA sequence that exists in all aerobic bacteria. Because of this, the PathoSEEK Total Aerobic Count test can detect all aerobic species, regardless of whether they grow in culture. Culture-based tests can only detect the species that grow in a given medium and timeframe. Conversely, qPCR can more effectively exclude off-target microbial species, such as yeasts and molds, which have been shown to grow in TAC culture medium.
Labs can use our PathoSEEK Microbial Safety Testing Platform to test for TAC in a variety of cannabis matrices. The PathoSEEK® Platform is the only method designed for and validated on cannabis flower, extracts, and a variety of infused products.