The infestation of flies that followed the dumping of slurry in fields surrounding Magħtab last year.

The spread of food-borne infection is one of the main health risks resulting from the use of untreated slurry on agricultural fields, according to two experts.

Both scientists agreed that the practice can potentially lead to bacterial and viral infections, and that washing the produce would not necessarily eliminate the risks.

The Sunday Times of Malta sought the advice of a food scientist and an expert on public health issues from two separate university faculties on whether the use of liquid manure from animal farms carried any health risks.

Over the past month, the newspaper has reported the use of slurry from animal farms by some farmers as fertiliser.

Its use is illegal, and the Ombudsman’s office is investigating the health and environmental risks.

Initial findings indicate the practice is geographically “widespread”.

Vasilis Valdramidis, Senior Lecturer at the Faculty of Health Sciences at the University of Malta said the use of liquid unprocessed animal slurry on agriculture fields goes against EU rules which, if not followed, could potentially lead to bacterial and viral infections.

“Washing the harvest with water, and/or vinegar, can reduce the microbial risks but not necessarily eliminate them,” he added.

He also referred to scientific reports on the possibility of bacteria entering fresh produce through, for example, the leaves – referred to as ‘bacterial internalisation’.

He added: “The food being grown would need to be tested for the levels of microbes to quantify these food safety risks, but the most important thing right now should be to ensure that EU requirements for slurry use are followed.

“This is the only way food consumers can be protected.”

Julian Mamo, Head of the Public Health Department at the University of Malta, said that the spread of infection could occur through various means. Research points to birds, insects and rodents, among others, as able to spread disease.

Dr Mamo also pointed to additional hazards including the possibility of resistant strains of bacteria being created due to antibiotics used in pigs.

“There are obviously very sound reasons why dumping untreated (liquid) manure is illegal,” Dr Mamo said, adding that the resulting increase in nitrates to the soil also poses a hazard to the water table.

Meanwhile the Magħtab Residents Association forwarded to The Sunday Times of Malta complaints filed in May last year after liquid manure was dumped on fields surrounding the community.

Washing the harvest with water, and/or vinegar, can reduce the risks but not necessarily eliminate them

John Portelli, a Magħtab resident, also documented a fly infestation that followed.

Farmers who spoke to The Sunday Times of Malta said those using slurry on fields were the exception, not the rule.

They called for action to be taken against the abuse, saying a few were harming the reputation of many.

There were 19 public complaints over the past two years on the spreading of liquid manure, Health Minister Konrad Mizzi revealed in Parliament this week.

Information on public complaints on slurry use released by the Health Ministry shows reports were received from Magħtab, Naxxar, Salina, Burmarrad, Birżebbuġa and Marsascala. Four were not confirmed.

In Gozo, the main complaints came from Xewkija, with more reports from Xagħra, Victoria, Għarb, Marsalforn and Għajnsielem.

Dumping slurry on agricultural fields is banned because the whole country is classified as a Nitrate Vulnerable Zone.

The Nitrate Action Programme document states the major source of nitrate pollution in groundwater is the excessive use of natural and artificial fertilisers in arable agricultural practices.

The document also states that data from a fertilisers survey indicates that the limit stipulated in the Nitrate Directive was being exceeded in almost all fields cultivated with irrigated vegetable crops, “in certain cases the limits are exceeded by more than 100 per cent”.

But soil samples taken from agricultural land in Burmarrad last month were found to be within permissible limits, Environment Minister Leo Brincat said in Parliament on Tuesday.