Almost a third of branded food products sold in the European Union have the same or similar packaging, but different contents, according to a report published by the European Commission on Monday.
However, the report did not find that there was a noticeable split between the east and west of the bloc, despite complaints from former communist countries that multinationals sell lower quality food in their markets.
The study into nearly 1,400 samples of 128 different food products in 19 EU countries found that 9% of products had identical and 22% similar package fronts, but different compositions.
The disparities included varied content of meat or fish, a greater fat content or a different type of sweetener in some EU countries compared to the product elsewhere.
Hungarian commissioner Tibor Navracsics said he was pleased that there was no evidence of an east-west divide, but described the findings as "mixed".
"I am worried that they uncovered up to one third of tested products having different compositions while being identically or similarly branded," he said in a statement.
Since Commission President Jean-Claude Junker made dual food standards an issue in his state of the union speech in 2017, the Commission has established a common way to test food products and set EU-wide rules to make similarly branded food have the same content.
The Commission said on Monday it would also provide 1.26 million euros ($1.44 million) of funding to help countries prepare for a new law to increase cooperation between EU countries on consumer protection, which will enter force in January 2020.