LONDON — The European Commission last week extended its investigation of Cargill’s planned takeover of the chocolate business of Archer Daniels Midland Co. to July 23 from July 8 after the two companies requested more time. The commission on Feb. 23 said it had opened a Phase II, or more in-depth, investigation of the transaction after its Phase I, or preliminary, investigation showed potential competition concerns in the supply of industrial chocolate to customers in Germany and the United Kingdom. Minneapolis-based Cargill on Sept. 2, 2014, initially announced its plan to purchase Chicago-based ADM’s global chocolate business for $440 million. The transaction includes three ADM European chocolate plants in Liverpool, United Kingdom; Manage, Belgium; and Mannheim, Germany, as well as three ADM North American chocolate plants in Milwaukee; Hazleton, Pa.; and Georgetown, Ont.