What is a food safe adhesive for plastic?

I make yoghurt. I put it in jars and cups for myself.

I want to make some to sell at the farmers market and so I need to put it in some plastic glasses.
I was thinking of using a plastic wine glass for individual serving size.

How can I safely adhere a plastic film over the mouth of the glass?

Picture of What is a food safe adhesive for plastic?
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ChrysN6 years ago
You can try gelatin or wheat paste. There is a great instructable here on how to make your own glue (though I wouldn't use the alum in the first recipe).
redorchestra (author) 6 years ago
I started sealing the top of yoghurt for myself with some paraffin wax. It works really well. You just break it open to eat the yoghurt.
orksecurity6 years ago
I presume you *are* going to refrigerate this properly until sale, right?

(If not, the best suggestion I can make is to go with proper canning... though gods only know what cooking would do to the yoghurt beyond killing the culture.)

Another quick thought: Use a refrigerated ice cream pushcart, sell yoghurt by the scoop from refrigerated containers, and you dodge the whole question of sealing the cups.

You may, or may not, want to find out whether the health department will let you get away with any of this and what their requirements will be. This may be over the line into needing restaurant-style certification.
iceng6 years ago
An ultra sonic weld head causes micro friction to make a strong weld bond of plastic parts in seconds and in a food grade safe manner.

verence iceng6 years ago
Yes, but unfortunately, the sonic welding machines are not cheap.
iceng verence6 years ago
Commercial units yes, but its only magnetostriction like a sonic cleaner.
Same thing that makes a transformer humm.  By aligning domains in iron
alloys a magnetic bar becomes fractionally longer when under a magnetic
coil.  Turn a coil ON / off fast enough and cause mechanical friction,
enough to melt plastics together.
This might be an interesting ible.

redorchestra (author)  iceng6 years ago
I'm interested!
verence6 years ago
Can you sell your product in a glass container with a screw-on lid?

I know the container would be expensive, but reusable (good, if you want to put a 'green' sticker on your stuff) and you can implement a kind of deposit scheme - customer pays something 50ct/1$ extra and gets the money back if the container is returned reasonably clean (and unbroken).
redorchestra (author)  verence6 years ago
I might try this too. I like the idea of a deposit and return scheme, but don't really have the resources yet. That may come later if everything goes well. :)
kevinhannan6 years ago
It's worth spending some serious time researching *how* you are going to deliver your product as cost-effectively as possible. Involve a few people as one person can rarely think of every outcome and possibility.

Some years ago I entertained the thought of doing a stall at a farmers market but ruled it our after the costs of complying with various bits of legislation, insurance and the rent of the stall. However, I was most shocked to discover the highest cost was the container(s) I wanted to sell my product in.

I discovered that I can still distribute my products legally to my "family" - in quotes as that is the legal word the authorities use. I now ask those who want my produce to provide their own clean container (although I do give it a quick boil wash if possible) or I can provide a suitable container at cost to them that they can re-use. Everybody understands why this is important and when they get the product cheaply or free they are delighted.

Also as a thank you for a good level of custom, I save some produce at christmas and give it away free when cash is harder to find. You have no idea just how welcome this is until you see their faces.

It's a great way to widen a circle of friends but you'll find the wasters and hangers-on looking for permanent freebies may disappoint you - it did me.

You may also find a friendly farmers-market vendor might tell you what they did and where they get their containers and how they solved other problems.

Good luck with your venture - I hope your answer(s) comes quickly and cheaply.
lemonie6 years ago

If you go looking for "disposable paper cups" you can find them with lids pretty cheaply.

rickharris6 years ago
Most liquid containers are heat welded.
Vyger6 years ago
A sealing adhesive tape would work and be easy to get off. A more professional option would be shrink wrap seals like what is used on most supermarket items. Do a Google search, I am sure there are some available for small operations. You would use a hair dryer to shrink them down.