I was buying some spoons and forks and knives made in China. Very nice and attractive design and it was written there stainless steel. After I was using them 1-3 times now I see a reddish-brown-colored under the so called stainless steel and I have no idea what is but I guess is copper and I am scarred copper can be poisonous and even fatal to organisms. Do you think is good to continue to use them ? Also if I will buy another how to know are better.