• Nutritionists advise consumers to always wash tomatoes with warm water or to peel off the outer skin before eating them.
• Tomato farmers mostly use the World Health Organisation class II pesticides, which are toxic and whose residues are likely to remain in the crop when used inappropriately.
Image: MERCY MUMO
Tomatoes are king when it is a matter of Kenyan meal.
They are not only the most consumed vegetable in Kenya, but also the second most profitable to farmers after potatoes.
However, a new study by Kenyatta University researchers suggests that tomatoes consumed in Kenya are contaminated with the toxic chemicals farmers use during production.
Some of the pesticides have been linked to cancer, malformation of the foetus and damage to the immune system.
According to the study, it is almost impossible for farmers to successfully grow tomatoes without the use of pesticides due to the vegetable's vulnerability to diseases and pests.
However, farmers routinely overuse them and harvest the vegetables prematurely before chemicals decay, against manufacturers' instructions.
“Noncompliance to laid down pesticide use standards has become a major risk to the environment and human health,” the study states.
It was conducted in 2017-18 all around Mwea Irrigation Scheme in Kirinyaga County, Kenya's largest grower of tomatoes. Farmers around the scheme produce over 50,000 tonnes annually.
The farmers mostly use World Health Organisation class II pesticides, which are toxic and whose residues are likely to remain in the crop when used inappropriately.
Those who grow tomatoes in greenhouses are most likely to abuse pesticides. They apply 12 pesticides on tomatoes.
“All the pesticides were applied at higher rates than is recommended,” the study titled Farmers’ Compliance to Pesticide Use Standards in Mwea Irrigation Scheme says.
It is published in the International Journal of Innovative Research and Advanced Studies.
Farmers growing tomatoes in open fields use about 57 different trade names of pesticides.
“Forty of these pesticides were applied at higher rates than those recommended by the manufacturers,” the study says.
Farmers also routinely flout manufacturers' advisories to delay harvesting until the pesticides decay.
Out of the 12 pesticides applied (in greenhouses), only two had Pre-Harvest Intervals (PHI) values that were significantly less than the manufacturer’s specified values.
“Farmers harvested tomatoes sprayed with these pesticides earlier than the manufacturer’s specified duration,” researchers say.
In open field farms, only 30 of the 57 pesticides had PHI values less than the manufacturer’s specified values.
The rampant abuse is mainly blamed on lack of training and sensitisation for farmers.
Interviews showed that 58 per cent of all farmers had not been trained on safe use of pesticides.
“Farmers mainly consulted each other which could be attributed to misuse and over use of the pesticides, some of which were toxic WHO Class II,” the study says.
Kenya also lacks well-equipped laboratories to test for such residues, which means such vegetables and fruit go directly to kitchens without the required tests.
The study was co-authored by Momanyi Violet and Dr Peterson Warutere from KU’s department of environmental and occupational health.
Other authors are Margaret Keraka from KU's School of Public Health and Deborah Abong’o from the Department of Chemistry at the University of Nairobi.
Nutritionists advise consumers to always wash tomatoes with warm water or to peel off the outer skin before eating them.
- mwaniki fm