Can an employer specify in an employment contract that an employee be required to work a minimum of 50 hours per week?

If an employer desired that a possible employee work a minimum of fifty (50) hours per week  as a condition of employment and the employee agrees to this condition, then there is nothing wrong with the agreement.

The issue then becomes one of whether or not overtime pay is required for any time worked per day or per week under the laws and regulations of the state where the employee is working the fifty (50) plus hours per week. This comes into play as to whether the employee working these hours is in a management or non-management role.

For further inquiries concerning specifics of your question, you might consider calling the labor department nearest you.

Good question.

This is perfectly legal. The law does not restrict the number of hours an employee may work, but merely requires that if the employee is hourly, he or she be paid for all hours worked--and if not exempt from ovetime, that he or she be paid overtime for hours over 40 in a week.

Employers have considerable discretion in setting the terms and conditions of employment, including hours worked, and can essentially require anything not itself illegal. Since it is not illegal to have employees work 50 (or more) hours a week, an employer may make this a condition of employment or a term in an employment contract, subject only to the obligations regarding hourly pay and overtime pay discussed above.