Is it possible to create completely food-safe prints with no post processing?

(Adam Steinmark) #1

Is it possible to create completely food-safe prints with no post processing?

In light of releasing new FDA approved food-safe PLA filament ( I’m asking this question. Even if you use a stainless steel nozzle and only FDA approved filament in your machine, it’s my understanding that due to the process of FDM/FFF printing the resultant parts are inherently porous and therefore become a breeding ground for bacteria. There are also a few lesser known manufactures creating antibacterial or antimicrobial filaments, would prints from this type of filament be completely food safe or are there other issues?

(黒い楓(Spice)) #2

You would want to flush your extruder with cleaning products before and after use. You also probably wouldn’t want to use a Bowden tube, because the Teflon could peal off and embed itself into the plastic. Also, you’d need an all metal hotend, since the cheaper ones have Teflon in the hot zone that will give off toxic materials when heated.

(Nita Vesa) #3

What I would worry about is similar to the issue with vaping: many (most?) vaping-products are considered food-safe by FDA and similar institutions in their original form, but once those liquids are burned research has shown that they form entirely new compounds that are no longer food-safe, with some of them being carcinogenic, certain ones causing popcorn-lung ( see e.g. ) and so on.

My point here is, even if the filament is considered food-safe in its shipping form, who’s to say it’s food-safe anymore after passing through a hot extruder? It might be food-safe at one temperature, it might become non-food-safe at another temperature – I am not aware of any proper research having been put into this and, personally, I would be rather wary of printing anything that’s in direct contact with foods and/or liquids meant for human-consumption.

(Duncan Gunn) #4

Micropores and rough texture are still issues. Think of it this way, your item might be squeaking clean as it it comes off the printer, but one use leaves it with added extras you won’t want in a weeks time.

Mostly, this appears fine but you could quite easily become very unlucky. I fear that there are too many who would chance it.

(MidnightVisions) #5

Food safe does not mean you can eat it, it means the PLA material won’t leech or cross contaminate the dood if it comes into contact with it. The machine that prints the PLA must also have the food safe stamp of approval.

(Nita Vesa) #6

@MidnightVisions I don’t see anyone saying anything about eating the filament itself.

(Adam Steinmark) #7

@Nita_Vesa That’s certainly something to consider but theoretically the filament would have essentially already passed through a hot extruder when it’s extruded from pellets.

@MidnightVisions all the filament manufactures say is that the product they provide to you is food safe, my worry is the act of processing it through a printer and creating micro pores makes it inherently unsafe. The question would be is antibacterial filament food safe or does it simply lower the amount of microbial life that would form in the pores.

The bottom line comes down to can 3D printing services that use FDA grade filament or antibacterial filament advertise food-safe 3D printed parts. Obviously we’re all willing to experiment on our own but does the FDA certification mean anything commercially?

(ThantiK) #8

More than likely FDA certification means next to nothing.

(Ben Koch) #9

Put some UV-LEDs beyond the extruder :smirk:
doh - I need to patent that :exploding_head:

(Taylor Landry) #10

There are 2 different questions within your query.

First, yes, it is possible to 3D print a completely food safe item with no post processing.

Second, no, it is not possible to make a completely food safe item with no post processing if you intend the part to be used more than once.

The issue is not chemicals leeching from the plastic. The issue with food safety is ability to sterilize it.

(MidnightVisions) #11

In the case of Canada, its Health Canada that would determine which materials can be used with which specific machine. While the material may be rated food safe, the machine that forms the PLA may not be. The manufacturing process must be able to form the PLA without creating macroscopic pores where bacteria could hide. In normal plastic tableware, cutlery and plates, the plastic injection molding process prevents microscopic pores from happening, so plastics approved for food contact is considered food safe.

The typical 3D printer can not create clean enough edges or surfaces for food contact purposes.

(Taylor Landry) #12

@MidnightVisions they can for single use items…

(黒い楓(Spice)) #13

@Ben_Koch Actually, it’s not a bad idea to build an enclosure for the printer that has sterilizing UV lights all throughout it.

(Baldur Norddahl) #14

@_Spice what is the point of UV light in a printer? No bacteria will survive going through the hotend. Bacteria in the product is not the issue at all.

(Ryan Carlyle) #15

“Food safe” is not an actual regulatory term, it’s marketing lingo. Approval for food contact varies by country and application but in general is contingent on the specific food being handled, and how. First the material must be safe for the application, and then it must be processed in a way suitable for the application, and then it must be used in a safe way. That whole process must be auditable and is what the government looks at, not just the raw material.

There are multiple issues to worry about:

  1. Whether the plastic leeches chemicals (eg food-grade ABS and polystyrene is widely used for packaging, but it is not suitable for contact with fats/oils)
  2. Whether the plastic absorbs or is damaged by the specific food (eg nylon is attacked by acids like citrus)
  3. Whether the product can be properly cleaned and sterilized between uses (eg if it has pores the answer is generally no UNLESS you can autoclave it)

As far as your personal safety goes — not poisoning yourself or getting salmonella — almost any 3D printer filament from the US or EU is perfectly fine for whatever you want to do. Some guidelines:

  1. No hot beverages in any printed plastic (and tbh probably shouldn’t put hot beverages in plastic at all to be safe, at least for kids and nursing/pregnant women)
  2. Natural/clear color filament (no pigment) is ideal. White and black filament are the safest pigments (titanium dioxide and carbon black) but only from highly reputable US/EU vendors (like Taulman) to avoid contamination. Never use cheap Chinese black for food contact, there are known cases of them hiding toxic junk in the black.
  3. If you use a printed part for prep of non-cooked foods (like slicing raw vegetables), meats, or egg-containing products like cookie dough, run the part through a modern dishwasher with a “sanitize” cycle between uses (or just make it one-time use)
  4. ABS is fine for dry foods, PETG and PLA and Nylon are better choices for wet food contact
(黒い楓(Spice)) #16

@Baldur_Norddahl Bacteria in the air or on the print bed settling on the product. It’s a bit overkill, but effective in eliminating any possible chances of contamination.

(MidnightVisions) #17

Soap and water will remove bacteria, its part of every manufacturing (canning) process for food grade products.

(Adam Steinmark) #18

@MidnightVisions due to the porous nature of 3D prints hand washing isn’t gonna cut it. You would need to use a dishwasher like @Ryan_Carlyle suggests

(MidnightVisions) #19

@Adam_Steinmark Steaming is another method to remove bacteria from production runs, but lets face it, this is all just theoretical.