No employee shall take or be allowed to take food into any room or apartment in any factory, mercantile establishment, mill or workshop, where white lead, arsenic, or other poisonous substances, or injurious or noxious fumes, dusts or gases under harmful conditions are present as the result of the business conducted by such factory, mercantile establishment, mill or workshop, and notice to this effect shall be posted in each room or apartment. Employees shall not remain in any such room or apartment during the time allowed for meals, and suitable provisions shall be made and maintained by the employer, when practicable, for enabling the employees to take their meals elsewhere in such establishment.