Flutterby™! : Food safe 3d printing

Hackaday: Food safe 3d printing

Matt Thomas] wanted to answer the question of whether 3D printed structures can be food-safe or even medical-safe, since there is an awful lot of opinion out there but not a lot of actual science about the subject. As a mechanical engineer who dabbles in medical technical matters, he designed as series of tests using a wide range of nasty-sounding pathogens, to find once and for all what works and what does not.

Though that blog post is August 2022, it references (and looks like a republishing in HTML of) The Impact of Sanitation Methods of 3D-printed Parts for Food and Medical Applications, January 2019 Advances in Science Technology and Engineering Systems Journal

Results from various testing methods used in hospitals and FDA approved microbial surface testing, indicate that 3D printed parts of PLA/PLA+ (Polylactic Acid), and PETG (Polyethylene terephthalate glycol) can be cleaned to safe levels using warm water (120 °F), and non-concentrated dish soap. Examination and verification of cleanliness were completed via Petri dish preparations, and protein residue testing. It was found that Colony Forming Units (CFU) and Plaque Forming Units (PFU) had been reduced by 90%. Experimental results indicate that using 2g of baking soda, when used with soapy water, eliminates biofilms by chemical and physical action, neutralizes acidic bacteria, and removes mucus. It is recommended (not required) and tested by surgical technicians, that a 2-minute room temperature bleach water soak (200ppm), after washing and rinsing should be done to ensure pathogens are at safe levels. Acetic acid from vinegar was tested as well via petri dish for CFU reduction and can effectively eradicate biofilms due to the ability to penetrate the biofilm matrix and the cell membrane. Acetic acid is not recommended for disinfecting, only for biofilm reduction. It is noted to the reader that sanitation in this context refers to the method of bringing a surface or object to safe levels of cleanliness for food or medical preparation and storage. Furthermore, mass spectrometry readings indicate that no contamination from heavy metals, or other toxins are present in PLA+, and PETG before and after printing. Lastly, filaments made from a pull-trusion method from recycled soda or water bottles has been tested and found to be safe.. When using 3D-printed items for liquids, it is highly recommended to coat the 3D-printed parts in resin.</bockquote>