The Saliva Clinical Trials, page-3

Considering that people would be breathing and farting regardless of whether it's into a bag or device, they'll be spreading the stuff anyhow. ADO's test is disposable as well and uses more plastic than a bag. But all that is irrelevant.

If you're interested in the breath stuff, here's some info:

This study aims to evaluate several of Owlstone Medical's Breath Biopsy aerosol respiratory droplet capture techniques for the detection of nCOVID-19. These are single use disposable breath capture devices with removable filters and fitted PVA strip that directly sample exhaled breath aerosols and therefore, directly sample the primary transmission route for the virus. They can be used independently and shipped for analysis for the presence of nCOVID-19 using established existing assays available in any reference lab

https://www.owlstonemedical.com/science-technology/breath-biopsy/

https://www.owlstonemedical.com/science-technology/research-case-studies/

The only thing that really matters is testing sensitivity, accuracy, and practicality. Hopefully we can win that race or at least lead it for a good amount of time.