McDonald’s Japan is to launch a new smartphone app for customer complaints as it looks to turn the page on a series of scares including the discovery of a human tooth in some fries.

The move comes with in-country sales sliding, profits plunging and the burger giant’s reputation in Japan badly dented. ‘We will introduce a new smartphone app customers can use to post their feelings, opinions and requests, aiming at strengthening our ability to listen to customers’ voices,’ McDonald’s Japan Holdings, the parent company, said in a statement issued this week. The firm also said it was reviewing its procedures for dealing with suspected cases of product tampering and will draft new rules on communication with customers by next month. The chain came in for heavy media criticism for its handling of incidents over the past year in which unexpected objects were discovered in food.

A human tooth was found in some french fries sold at an Osaka outlet last year, the firm admitted in January, although it said it did not know how the contamination had occurred.

McDonald’s said there were no employees missing a tooth at the outlet and it believed there was a very low possibility of contamination at the US factory that had shipped the chips. Two days later, a Japanese woman claimed to have discovered what was later identified as ‘dental material’ in a McDonald’s hamburger from northernmost Hokkaido in September. Japanese media reported several other cases of contamination, including a piece of metal in a pancake.

The foreign bodies problems marked another public relations setback for a firm still struggling to recover from a scandal last summer when a Chinese supplier was found to be mixing out-of-date meat with fresh produce. Then late last year the company had to airlift an emergency supply of french fries from the US after a chip shortage resulted in rationing at restaurants across Japan. In February, the firm said it had lost a worse-than-expected 21.8 billion yen ($186 million) for 2014 - against a year-earlier profit and recording its first loss in 11 years. Nationwide sales in January were down 39 percent on year. McDonald’s Japan this week announced the appointment of new chairman and chief operating officer. The unit’s Canadian chief executive Sarah Casanova remains in place.