Specified risk material (SRM) is a big word that describes parts of an animal that could cause a sickness called BSE, also known as mad cow disease. BSE is dangerous for humans and could make them really sick.
Animals that could have BSE are called "high-risk" animals, and their parts that could make people sick are called SRMs.
SRMs are parts of an animal that you may have heard of before, such as the spinal cord and brain. Other SRMs include the tonsils, eyes, and parts that are close to the backbone.
To keep people safe, the U.S. government has a rule that says we can't eat SRMs, and we have to remove them from animals before turning them into food. The rule also says that if we use any equipment that touched or was close to the SRMs, we have to clean it really well to make sure it's safe to use again.
So, in summary, SRM is the parts of an animal that could cause BSE, a very dangerous sickness for humans. The government has rules to make sure we don't eat these parts and clean any equipment that may come in contact with them.