Cooperatives or employee owned companies are capitalistic--they are privately owned just as an individually owned business or a corporation run by a board of directors.
Socialism is publicly owned (government).
Socialism, by definition, is who controls the means of production and distribution.
Programs like Social Security, welfare programs, etc. are not socialistic because they do not involve the production and distribution of goods and services. Medicare is not socialist because our healthcare industry is privately owned and operated (except the VA).
An example of socialism is China in which steel production and other major industries are entirely controlled by the government or government is a major owner of the business.
Communism is a political system and capitalism and socialism are economic systems. Communism, by definition, has a socialist economic system. Being communist is not much more than having political control by the communist party and claiming to be communist.