I only read the abstract, but theyre looking at big (~mm) particles. Those wont be passing through the digestive system to the muscle tissue. Looks like theyre

I only read the abstract, but theyre looking at big (~mm) particles. Those wont be passing through the digestive system to the muscle tissue. Looks like theyre also digesting/processing samples so they cant precisely isolate the locations in the sampled tissues. Much smaller (nanometer) particles can pass through tissues and migrate in to the body. But accurately detecting those sizes isnt reliably achievable AFAIK.