(a) cause or suffer any person to milk cows or to handle vessels used for containing milk for sale, or in any way to take part or assist in the conduct of such trade or business, unless such person has been certified as fit by a medical officer;
(b) cause or suffer any person, although he or she has been duly certified as aforesaid, who at any time appears to be suffering from any contagious or infectious disease, to milk cows, or to handle vessels used for containing milk for sale or in any way to take part or assist in the conduct of such trade or business;
(c) cause or suffer any cow to be milked until its udder and hands of the milker have been cleaned and the utensils thoroughly cleaned and scaled.