A Shanghai company supplying free gift packs to residents in Yangpu District is under investigation, Shanghai's market regulators revealed on Sunday night.Some pork packages in the gift packs were found to have fabricated production dates, according to the Shanghai Administration for Market Regulation.Authorities of Jiangpu Subdistrict procured the batch of sauce-flavored pork ribs from Benlai.com, the Shanghai-based online food platform, and delivered the goods to locked-down residents recently.