When the Secretary in the exercise of his duties requests of the Commission that it make investigations and reports in any case.

In any investigation of, or proceeding for the prevention of, an alleged violation of any Act administered by the Commission, arising out of acts or transactions involving meat, meat food products, or livestock products in unmanufactured form, if the Commission determines that effective exercise of its power or jurisdiction with respect to retail sales of any such commodities is or will be impaired by the absence of power or jurisdiction over all acts or transactions involving such commodities in such investigation or proceeding. In order to avoid unnecessary duplication of effort by the Government and burdens upon the industry, the Commissioner shall notify the Secretary of such determination, the reasons therefor, and the acts or transactions involved, and shall not exercise power or jurisdiction with regard to acts or transactions (other than retail sales) involving such commodities if the Secretary within ten days from the date of receipt of the notice notifies the Commission that there is pending in his Department an investigation of, or proceeding for the prevention of, an alleged violation of this chapter involving the same subject matter.