Food adulteration and contamination can certainly be an issue in some cases, but the assertion that half of our food is made of plastic is not supported by credible scientific evidence. Here are a few key points on this topic:

1. Rice and other grains: Rice and other common grains like wheat, corn, etc. are natural agricultural products grown from plants. They do not naturally contain or consist of any significant amounts of plastic.
2. Food safety regulations: Most countries have strict food safety regulations and standards in place to ensure that the food supply is free from harmful adulterants, including plastics. Regulatory agencies routinely monitor and test food products.
3. Isolated incidents vs. systemic issue: While there may be isolated incidents of food adulteration involving plastics or other contaminants, this does not mean that half of all food is made of plastic, which would represent an extreme and implausible scenario.
4. Lack of scientific evidence: There does not appear to be any reputable scientific studies or data that substantiate the claim that 50% of our food is plastic. Such an extraordinary claim would require very robust and verifiable evidence.

Unless you have access to credible, well-documented information from reliable sources to support this specific claim, I would caution against generalizing or spreading unverified information about the food supply being 50% plastic. It’s important to be cautious about making such strong assertions without solid evidence.