It is very well defined. I can summarise it in one sentence: "In 1989, the European Communities banned the import of meat that contained artificial beef growth

It is very well defined. I can summarise it in one sentence: "In 1989, the European Communities banned the import of meat that contained artificial beef growth hormones,[a] although they were approved for use in the United States." you can read about it in more depth here: https://en.wikipedia.org/wiki/Beef_hormone_controversy https://en.wikipedia.org/wiki/Beef_hormone_controversy That is about the beef. There is a different controversy about poultry meat. There the controversy is that under EU law, cold air and water are the only substances that can be used to decontaminate poultry. In the US chlorine rinses are also permitted. In other words artificial beef growth hormones and chlorine rinsed chicken are the two points which is what we mean by 'substandard' in this conversation.