Dirty water taints food crops

Food safety researchers track multidrug-resistant bacteria in irrigation used to spray and clean

- By Lise Korsten By Loandi Richter-Mouton

Water is essential at all stages of food production, from irrigation and food processing to washing fruit and vegetables before we eat them.

Crops and livestock need it to grow, but water can also be contaminated by pathogens (any organism that causes disease), heavy metals and chemicals.

These can be considered a potential food safety hazard when they enter the food chain. For example, contaminated irrigation water can transfer pathogens like Escherichia coli to fruit and vegetables. Eating these raw and without washing them properly can lead to severe stomach cramps, diarrhoea, nausea and fever.

We are a team of researchers from the University of Pretoria and the Water Research Commission who have investigated bacterial pathogens in water sources for the past 20 years. We've developed ways to determine whether water is of good quality when used before and after harvesting produce.

With about 40 years of combined experience, we are also identifying potential hotspot environments for contamination. We're currently tracking multidrug-resistant bacteria in South Africa's water and assessing the implications for food safety. We have also analysed the complete supply chains of fresh produce using microbiological methods to investigate what contaminants might be circulating in vegetable production and contaminated irrigation water.

Our research is focused on ensuring that the food reaching consumers' tables does not pose hidden health risks. Over the years, we've learnt key lessons: