Reducing Cross Contamination in Your Lab

Cross Contamination

Cross Contamination – noun – “inadvertent transfer of bacteria or other contaminants from one area, substance, etc., to an additional particularly simply because of unsanitary dealing with strategies. – (Mariam Webster, 2021). Cross contamination is not a new idea in the clinical and food stuff lab industries numerous services have substantial structure facets as effectively as SOPs to deliver the least sum of contaminants into the lab location. For hashish labs, even so, normally the exponential development sales opportunities to a circumstance exactly where the lab just isn’t large more than enough for the selection of samples processed and range of analytical instruments and staff wanted to process them. Cross contamination for cannabis labs can signify delayed final results, heightened occurrences of bogus positives, and in the long run lost customers – why would you pay for analysis of your clean solution in a filthy facility? The next actions can save you the problems connected with cross contamination:

Clean (and dry) your hands correctly

Flash again to early pandemic times when the Tik Tok “Ghen Co Vy” hand washing music was the hotness – we experienced minimal to no thought that the illness would be fueled mostly by aerosol transmission, but the premise is the identical, superior hand hygiene is very good to lower cross contamination. Hands are typically the resource of micro organism, the two resident (listed here for the long haul attached to your fingers) and transient (simple to eliminate just passing via), as they come into get hold of with surfaces from the bathroom to the pipettor each day (Robinson et al, 2016). Glove use coupled with suitable hand washing are very good techniques to lessen cross contamination from staff to a item sample. On top of that, the style of hand drying procedure can lower the microbial load on the toilet floors and, subsequently tracked into the lab. A 2013 analyze shown almost double the contamination from air blade technologies compared to applying a paper towel to dry your hands (Margas et al, 2013).

Structure Your Lab for Separation

Microbes are migratory. In reality, E. coli can travel at speeds up to 15 body lengths for every next. In contrast to the fastest Olympians working the 4X100m relay, with an normal speed of 35 toes per 2nd or 6 overall body lengths, this bacterium is a gold medal winner, but we do not want that in the lab setting (Milo and Phillips, 2021). New lab style retains this concept of bacterial journey in brain, but for all those labs without having a new develop, measures can be designed to avert contamination:

  • Attempt to retain site visitors flow going in just one direction. Retracing actions can direct to contamination of a preceding work station
  • Use individual products (e.g. cupboards, pipettes) for every single process/move
  • Separate pre- and submit-pcr regions
  • Actual physical separation – use various rooms, include partitions, partitions, and many others.

Create, Coach and Adhere to SOPs

Style and design SOPs that involve every thing- from cleanliness to check procedures and sanitation.

High turnover for staff in labs results in myriad troubles. It doesn’t get very long for a lab that is buttoned up with cohesive workflows to develop into a willy-nilly hodgepodge of very poor lab methods. A lack of codified Regular Functioning Procedures (SOPs) can lead to a lab rife with contaminants and no apparent way to troubleshoot the situation. Labs must layout stringent SOPs that consist of almost everything from hand cleanliness to examination strategies and sanitation. Penned SOPs, in accordance to the WHO, should be offered at all work stations in their most new model in purchase to reduce biased final results from testing (WHO, 2009). These SOPs should really be relayed to every single new employee and training on up-to-date SOPs ought to be executed on an ongoing basis. In accordance to Sutton, 2010, laboratory SOPs can be broken down into the subsequent classes:

  • High-quality specifications
  • Media
  • Cultures
  • Products
  • Schooling
  • Sample dealing with
  • Lab operations
  • Screening methodology
  • Data managing/reporting/archiving
  • Investigations

Build Controls and Check Benefits

Scanning electron micrograph shows a colony of Salmonella typhimurium bacteria. Photo courtesy of CDC, Janice Haney CarrScanning electron micrograph shows a colony of Salmonella typhimurium microbes. Image courtesy of CDC, Janice Haney Carr

It may well be complicated for labs to maintain tabs on positivity and fail rates, but these are essential features of a QC program. For microbiological assessment, labs really should use an inner positive manage to validate that 1) the method is performing effectively and 2) positives are a end result of goal analytes uncovered in the goal matrix, not an inside lab contamination pressure. Beneficial controls can be an organism of option, this kind of as Salmonella Tranoroa, and can be tagged with a marker, this kind of as Inexperienced Fluorescent Protein in get to differentiate the control pressure. These controls will permit a lab tech to discriminate among a obviously contaminated specimen vs. a positive as a consequence of cross-contamination.

Labs really should, in addition to possessing good QC techniques, retain keep track of of fall short prices and positivity prices. This can be done as full lab final results by examination, but also can be damaged down into buyers. For occasion, a lab fail rate for pesticides averages 4% for dried flower samples. If, all through a offered time period of assessment, this amount jumps earlier 6% or falls under 2%, their may well be an problem with instrumentation, personnel or the solution alone. At the time contamination is ruled out, labs can then existing proof of spikes in fail costs to growers who can then remediate in their have facilities. These initiatives in concert will inherently generate down fail costs, maximize lab potential and efficiency, and result in charge savings for all get-togethers connected.

Ongoing Improvement is the Vital

Cannabis testing labs are, as opposed to their foods and scientific counterparts, somewhat new. The lack of reliable condition and federal regulation coupled with unfathomable advancement every single 12 months, means many labs have been in the “build the aircraft as you fly” method. As the lab natural environment matures, simple QC, SOP and cleanliness alterations can make an incremental variations and travel improvements for labs as perfectly as growers and companies they aid. Lab management can, and need to, get methods to lower cross contamination, enhance efficiency and lower costs The to start with move is constantly the most difficult, but constant improvement are unable to start out until it has been taken.


Margas, E, Maguire, E, Berland, C. R, Welander, F, & Holah, J. T. (2013). Evaluation of the environmental microbiological cross contamination subsequent hand drying with paper hand towels or an air blade dryer. Journal of Utilized Microbiology, 115(2), 572-582.

Mariam Webster (2021. Cross contamination. Retrieved from

Milo, M., and Phillips, R. (2021). How rapidly do cells go? Cell biology by the numbers. Retrieved from http://e

Robinson, Andrew L, Lee, Hyun Jung, Kwon, Junehee, Todd, Ewen, Perez Rodriguez, Fernando, & Ryu, Dojin. (2016). Adequate Hand Washing and Glove Use Are Vital To Lessen Cross-Contamination from Palms with Higher Bacterial Masses. Journal of Food stuff Safety, 79(2), 304–308.

Sutton, Scott. (2010). The worth of a solid SOP process in the QC microbiology lab. Journal of GXP Compliance, 14(2), 44.

Entire world Overall health Group. (2009). Very good Laboratory Exercise Handbook. Retrieved from