In its latest financial update, the global fast food chain reported a drop in sales in the Asia/Pacific, Middle East and Africa (APMEA) region of 7.3%.
Sales also fell in the US - down 3.2% - which the firm put down to "continuing broad-based challenges".
Europe saw a marginal sales increase of 0.5%, as a result of a strong performance in France and the UK.
Sales took a hit in the APMEA region following the revelations last month about quality and safety issues at a supplier to McDonald’s and other fast food chains, including KFC, in China.
As reported by GlobalMeatNews, allegations were made against Husi Food Co, the Chinese arm of US-based supplier OSI Group, about the re-use of expired raw materials in the production and processing of food after uncover filming was carried out by a local television channel.
Although McDonald’s halted use of products by this company, sales in China, Japan and other markets experience "a significant negative impact", with the affected representing around 10% of its total global sales.
The firm said that as a result, it was undertaking recovery strategies to restore customers’ trust in the brand.
Commenting on the results, Don Thompson, president and chief executive, McDonald’s, said: "Although July’s results were not in-line with McDonald’s expectations, we intend to strengthen our performance by addressing the current business headwinds with the discipline and conviction that inspire our customers’ trust and loyalty."