discussion / Conservation Dogs  / 30 August 2021

Longevity of Scented Gauze

Hi folks,

I'm planning a new project where we'll be using residual scent on gauze to help imprint a dog on turtles, and I'm wondering how many times a gauze can be frozen and thawed before it should be discarded (that is before the odor degrades). Anyone have advice?

Background: I don't have this species of turtle in captivity but I have a colleague who does and is allowing us to swab his turtles and to train with the live turtles while we visit. We'll be rubbing the gauze on the neck and arms of the turtles (like Cablk and Heaton 2006), and I plan to freeze the gauze for future training sessions.  Can we get multiple freezing/thawing cycles from an animal-scented gauze so that we can train with it on multiple days?



There are a number of factors to consider here:

Firstly, gauze selection and preparation. 

Sample collection.

Collection of distractor/control scents

Storage to include immediate storage (mylar bags, Borosilicate glass, Mason jars etc.) and then freezer or fridge.

The best gauze is Dukal unsterilized. Rinse the gauze in Ethanol and then dry in an oven 150f for 15mins. Store all unused gauze together until ready to use. 

Ensure the person collecting uses disposable gloves (not powdered or chlorinated) and changes the gloves for each gauze. Rinse the turtle with clean unchlorinated water before scent collection to remove tank water and environmental odours. 

As soon as sample is collected place in Mylar bag or Borosilicate jar or whatever you are using and seal. (Do not touch the outside of container with contaminated (scented) gloves). Use stainless steel tweezers if needed.

Make sure the person prepares controls (handles gauze without collection scent) and distractors (collect various scents) in exactly the same way and store them the same.

I do not typically freeze reptile samples as the scent can be delicate. I store in the fridge. Ensure all controls and distractors are stored the same or the dogs will learn to smell the storage and not the target (I have had that happen).  

Once open I typical do not use for more than 30mins (if that) then dispose. The problem is the scent cannot replicate as there is not source for the odour and it will burn off quickly depending on the climatic conditions. I have stored samples for 3 weeks without issue but once open the deteriate fast. 

Hope this helps.