Which group did Stalin use propaganda against to blame for the food shortages in The Soviet Union?

Stalin blamed food shortage on the Kulaks. They were originally independent farmers from the times of the Russian Empire, who became wealthy after the Stolypin reform.

In the early 1930s, Stalin led a collectivization campaign to seize their properties. They had previously been accused of being class enemies to the poorer peasants, as well as to benefit from famine.