- Zearalenone is a fungal toxin infesting cereals such as wheat, maize and barley.
- It attacks crops while they are growing, but can also develop when cereals are stored without being dried fully.
- While numerous studies document this toxin in cereals across the world, no data existed for India until now.
- Journal of Food Science study detected zearalenone in wheat, rice, corn and oats from markets in Uttar Pradesh.
- The Food Safety and Standards Authority of India does not impose maximum limits for zearalenone, though the European Union (EU) does.
- Twenty-four of the U.P. samples exceeded the EU regulatory limits of 100-200 mcg/kg of cereals.
- Based on this, the authors say India should set limits on zearalenone in cereals.
How did it come about?
- Fungal toxins are commonly found in food, and can be a public health concern.
- India regulates the levels of some of these, including aflatoxin, deoxynivalenol, ergot and patulin.
- The first three infest cereals, while patulin is found in apples.
- Each of these toxins has been associated with disease outbreaks.
- For example, in 1974, a hepatitis outbreak in Rajasthan and Gujarat, which made 398 people sick and killed 106, was linked to aflatoxin in maize.
- Meanwhile, chronic aflatoxin consumption has been shown to cause liver cancer.
- Given this, the International Agency for Research on Cancer (IARC) classifies aflatoxin as a Group 1 carcinogen, meaning there is enough evidence for its carcinogenicity.
- In zearalenone’s case, there is no strong evidence of toxicity in humans so far, though several research groups are investigating.
- As a result, the IARC classifies it as a Group 3 carcinogen, which means evidence is not sufficient for an evaluation yet.
Why does it matter?
- Zearalenone behaves like oestrogen, the female sex hormone, and could cause endocrine disturbances in humans. Its nasty effects in animals, such as pigs, are documented.
- When fed with mouldy corn, pigs develop inflamed vaginas, infertility and other symptoms.
- This is why countries like Brazil regulate zearalenone levels in animal feed.
- In humans, the data are fuzzier.
- It is probably dangerous to humans too, but to be certain, we need to know how much humans consume, how it is metabolised, and how exposure is correlated with disease.
- Some experiments suggest its ill-effects: in one, when oestrogen-sensitive breast cancer cells were exposed to the chemical in a lab, they proliferated.
- In 2014, a Tunisian case-control study found a correlation between a zearalenone metabolite in urine and breast-cancer risk in women.
- Average daily consumption through wheat and rice was 0.27 and 0.3 mcg/kg of body weight — higher than the EU limit of 0.25 mcg/kg.
- In highly contaminated samples, exposure could be as high as 16.9 times the EU limit.
- More data are needed from cereals in other States, and from other storage conditions, before India decides to set limits.
- Since zearalenone favours cool climates, such contamination could be limited to a few States.
- Also, strong epidemiological data linking human zearalenone levels with diseases such as breast cancer are important.
