An "alarming number" of 400 dogs are thought to have died over the past month in Zambia after eating contaminated maize and humans could be at risk too, the country's health minister has said.

Elijah Muchima announced that approximately half of the 25 samples taken from milling companies were found to contain exceedingly high levels of aflatoxins, a poisonous substance produced by fungi.

Maize is the staple food in Zambia and Mr Muchima said the test results were "of great concern due to the several health implications for [the] population".

The World Health Organization (WHO) says there is evidence aflatoxins can cause liver cancer in humans.

Authorities launched an investigation into the nation's maize supply after Diamond TV, a Zambian broadcaster, found dozens of dogs had died from aflatoxin poisoning.

It was suspected they died after eating dog food containing contaminated maize.

In their investigation, the authorities took samples from 10 milling companies that make maize-based dog food and also process the grain to make maize meal, which is consumed by humans.

The health ministry has not reported any human deaths resulting from contaminated maize. However sources at the Zambia National Public Health Institute say they are currently trying to ascertain if the spoiled grains have had on impact on the general public.

Following the authorities' investigation, "affected batches" of maize meal have been recalled and seizure notices have been issued to "affected companies", Mr Muchima said. He did not name these companies or any specific maize meal brands.

Prior to Diamond TV's report, only Farmfeed, a dog-food processing company, had recalled its products.

In his press briefing on Tuesday, Mr Muchima said climate change and the impact of Zambia's recent drought had "exacerbated the occurrence of aflatoxin this season".

Like much of southern Africa, Zambia was hit by a severe drought earlier this year. An estimated one million subsistence farmers experienced damaged crops and maize supplies in the country are still critically low.

Maize provides around 60% of the population's daily calorie intake, according to the US agriculture department, causing politicians and the public to worry about the contaminated batches.

"Govt says 400 dogs have died due to toxins in some brands of [maize] meal. I’m a victim too. I lost over 6 big dogs over a period of 1 week," Sunday Chanda, an opposition member of parliament, wrote on social media platform X.

"Govt says 'it’s still investigating how wide the toxic maize has spread'. Listen, the bad [maize] meal is still out there being consumed!"

Another Zambian X user questioned why the health minister had not named the maize meal brands that were being recalled.

“We have the right to know what we’re feeding our families,” they wrote.

The Millers Association of Zambia, which represents milling companies across the country, said its businesses were working hard to ensure that the problem is resolved and the public is safe.

“We are still investigating the source of this contaminated grain and have heightened our surveillance of the product on the market," Andrew Chintala, president of the association, said.

"We have not been testing much for aflatoxin previously because this is the first time we’re experiencing this case of high aflatoxin, for which we are still investigating the cause."

Mr Muchima said the government had also extended surveillance throughout the country and stepped up sampling efforts.