Research: Tomato paste adulteration

Two research articles were published in recent months showing unauthorised additives, and notably erythrosine and starch, were found in tomato paste sold on the Lebanese and Ghanaian markets.

A study by the Kwame Nkrumah University of Science and Technology on tomato paste sold in Ghana has found traces of both starch and erythrosine in some samples.
Tomato concentrate has become a convenient food item commonly used in Ghanaian homes, fast food outlets, and restaurants as it offers a relatively cheap and quick alternative to fresh tomatoes, especially when tomatoes are out of season. Over the years, concerns have arisen over the safety of tomato concentrate brands on the Ghanaian market. The study, conducted in Kumasi and Accra, aimed to assess the quality of tomato concentrates being sold. Eight different brands that conformed to standard labelling requirements were selected. As well as the  total natural tomato content in some of the sampled brands falling outside the recommended range, alarmingly, erythrosine was detected in two samples, even though it was not indicated on the labels. The study also found starch content ranging from 1g/100g to 24g/100g in some samples.

Erythrosine, also called Red Dye No. 3, is used as a colourant in various foods, including toffees, candies, and drinks, but is not allowed in tomato paste by the Ghana Food and Drugs Authority (FDA), as it is around the world and by Codex Alimentarius. 

In January, the U.S. Food and Drug Administration completely banned erythrosine from food products due to its potential health risks and has given manufacturers two years to remove it from shelves and eliminate its use entirely.

Another research study aimed to evaluate the quality and potential adulteration with starch in tomato paste products available in the Lebanese market revealed that 37% of the 41 samples failed to meet starch usage standards, and 27% did not comply with the required total soluble solids (>24%). A comparison of local and imported tomato paste products showed that among local samples, 48% did not comply with the starch usage standard, and 26% failed to meet the required total soluble solids level. In contrast, imported samples adhered to starch usage standards, although 30% did not comply with TSS levels. This study highlights the prevalence of adulteration in local and imported tomato paste products in Lebanon and calls for further enforcement measures to ensure consumer protection and fair trade.
 
References: 
– Boakye A, Avor DD, Amponsah IK, Appaw WO, Owusu-Ansah L, Adjei S, Baah MK, Addotey JN. Quality Assessment of Tomato Paste Products on the Ghanaian Market: An Insight Into Their Possible Adulteration. Int J Food Sci. 2024 Sep 9;2024:8285434. doi: 10.1155/2024/8285434. PMID: 39285917; PMCID: PMC11405106.
Full text: https://onlinelibrary.wiley.com/doi/10.1155/2024/8285434
 
– Habib F, Khazaal S, Bou Yazbeck E, Debs E, Sunoqrot S, Louka N and El Darra N (2025) Adulteration and quality assessment of tomato paste: a study of the Lebanese market. Front. Nutr. 12:1559287. doi: 10.3389/fnut.2025.1559287
Full text: https://www.frontiersin.org/journals/nutrition/articles/10.3389/fnut.2025.1559287/full
 
Sources: Kwame Nkrumah University of Science and Technology, Beirut Arab University