Plastics that come in contact with your food or drink ‘should’ be safe based on the following general information.
Look for the Recycle symbol (often on the bottom of the container) and read the number located inside the symbol.
The following list cross-references the recycle number (recycling symbol) with what is generally considered safe for food (or not safe).
Plastics Considered Safe for Food & Drink
#1 PETE (polyethylene terephthalate)
#2 HDPE (high density polyethylene) *see note below
#4 LDPE (low density polyethylene)
#5 PP (polypropylene)
Plastic Water Bottles or Soft Drink Containers
#1 PETE (polyethylene terephthalate) Used for typical water, soda, and juice bottles. They are not designed for reuse however.
Risky Plastics Not Safe for Food and Drink
These plastics may leach or have hazardous ingredients:
#3 PVC (polyvinyl chloride) carcinogens during manufacture and incineration
#6 PS (polystyrene) possible carcinogen
#7 PC (usually polycarbonate, sometimes labeled PC) may leach BPA (Bisphenol-A)
Food Grade Buckets
5 gallon ‘food grade’ buckets are made of #2 HDPE, and are generally opaque or mostly opaque which minimizes the amount of light penetration. If the bucket is considered ‘food grade’ it is typically marketed as such and / or labeled “Food Grade”, “Food Safe”, etc.
Some food grade buckets or containers will include a cup & fork symbol as an indicator. A food-grade bucket or container might also be specifically marked as USDA approved (or FDA or NSF approved).
If you will be storing food directly in a plastic bucket or container, or if you will be using the container for drinking water, you might verify the material is food-safe before you purchase.
The typical ‘blue’ water storage containers or water barrels are also made of high density polyethylene #2 HDPE and are marketed as food safe.
All food grade buckets are made of #2 HDPE (high density polyethylene),
but not all #2 HDPE buckets are apparently food grade.
Buckets that are not food grade may out-gas and leach into the container, as well as into the contents held within the container.
This is what I’ve read about it:
#2 HDPE buckets that are not food grade may have been manufactured with a non-food-grade “mold release agent”.
In some processes, a mold release agent is what is used to help get the newly shaped plastic off of the hard mold that it was shaped from during the manufacturing process. Without the release agent, the new plastic shape will likely stick to the mold. Some mold release agents enable much faster production than others, but may be toxic to your health if later used with food.
Other processes apparently do not use a mold release agent and only use high pressure compressed air to blow the bottles into shape on the inside. No mold release agent of any kind is used inside the bottles of this process.
If you are unsure, you might simply contact the supplier or manufacturer to confirm.