If slaughtering, carcass preparation, or processing of any meat, meat products, poultry, or poultry products, or training of licensed livestock meat inspectors or licensed processing inspectors is conducted in an establishment licensed under Article 8 (commencing with Section 19010) during hours considered overtime for state employees or on legal holidays, the owner or operator of the establishment, by contract or agreement with the department, shall pay the additional costs for salaries and expenses for persons employed by the department, as determined by the department, to conduct the necessary inspection work or training during the overtime period.