It says it “shall have the power,” not, “it must do.”
Abuse of the General Welfare clause is the most-employed method of unconstitutional expansion of Federal powers.
In the case of food safety, I have a feeling that people would react strongly and negatively should the government fail to fulfil its constitutional duty to promote the general welfare.
When you buy produce, don't you want to know that it was grown by people who practice basic hygiene, and that human waste wasn't used as a fertilizer? How on earth is the free market going to assure that? How would you keep dishonest people from lying about growing conditions, without some means of holding them accountable? How do you, as a customer, know anything about that produce? How would we have known that contaminated cantaloupe was killing people, without the systematic procedures that exist for identifying such incidents? There are reasons there are food safety laws.
Abuse of the General Welfare clause is the most-employed method of unconstitutional expansion of Federal powers.
Abuse of any part of the constitution happens because voters keep electing people who promise goodies in exchange for power. I do not think there is a way to write a constitution that makes it unabusable. It should not be possible for unions to buy politicians, but they do. The problem is the voters.