4.—(1) It is the duty of each food authority within its area and each port health authority within its district to execute and enforce these Regulations, the Commission Regulation and Commission Regulation 124/2009.
(2) The competent authority for the purposes of—
(a)Article 2(2) (justification by food business operators of concentration or dilution factors), and
(b)Article 1(1) of Commission Regulation 124/2009 (relating to the duty to investigate the reasons for the contamination),
is the authority having the duty to enforce under paragraph (1).