There are persistent reports that some of the foodstuffs we eat are unsafe. Such information has left many worried and a number of questions unanswered. Ideally, when farmers grow crops, they spray them with pesticides to control insects, flies, weeds and microorganisms.
Julius Peter Ahangaana, an agronomist and acting farm manager at Makerere University Agricultural Research Institute, Kabanyolo, says chemicals have both positive and negative effects on crops.
On a positive note, the chemicals help eradicate pests and diseases in plants while on a negative side, the spray residues left on the crops can cause a number of health complications to humans.
Ahangaana says the effects depend on how a particular chemical was used during the farming stage.
“For instance, if a farmer sprayed a high concentration of a particular chemical on a crop than recommended, the effects could be severe after consumption,” he says.
He adds that when spraying is done when the crops have matured, the biodegrading (the breaking down) process of the chemical becomes difficult.
“In such a situation, the crop has already matured and will no longer be able to break down sprayed chemicals. Such crops will, therefore, lead to health complications after ingestion,” he says.
On the other hand, some chemicals become dangerous for human consumption during the farming stage when they are exposed to certain environmental conditions.
Handling fruits and vegetables
Edgar Twinomujuni, a public health nutritionist, says proper handling during preparation of fruits and vegetables is essential to avoid consumption of pesticide residue.
“Make sure that you always wash your fruits and vegetables and dry them with a clean cloth or paper towel when possible before eating them. This should be done under running water before either consumption or preparation,” he says.
Using salt water baths and diluted vinegar can be another method of removing chemicals from fruits and vegetables, Twinomujuni says.
He also recommends blanching. This is a process of immersing the vegetables in warm water before either eating or cooking them. This is in order to remove any residue that maybe left on the surfaces of the vegetables.
The other option is peeling and scrapping of fruits and vegetables under clean running water. This is in order to remove the outer layer that may contain pockets of the chemicals.
Wash your produce in running water. You do not need any special washes. Researchers have compared rinsing fruit and vegetables in plain water for one minute with washing them with vegetable washes (four different ones) and a solution of dishwashing soap and water.
Water alone was as effective as any of the washes or soap. Rubbing produce with soft skins such as peaches or using a vegetable brush on harder items such as potatoes or carrots will help remove residues, dirt and germs.
The health dangers
Dr Kenneth Bagonza, a general medical practitioner at Aga Khan University Hospital, says before a chemical is brought onto the market for use, a number of studies and tests are conducted.
“They will look at a number of things including whether the substance has any cancer causing risks to human beings,” he says. If the health risks cited are too many, Bagonza says concerned authorities will sanction against the use of such chemicals.
For a pesticide such as organophosphate, the general medical practitioner says poisoning occurs when an individual has been overly exposed mostly during the spraying rather than consumption stage.
Meanwhile, Dr Vincent Karuhanga, a healthcare practitioner at Friends Polyclinic, says pesticides when consumed in any food may trigger cancer by either disrupting hormones or damaging the Deoxyribonucleic Acid (DNA) of the body. DNA is a molecule that carries genetic instructions used in the growth of the body.
“Pesticides may trigger a number of cancers including breast, leukemia and lymphoma, among others,” Karuhanga says.
Breast cancer occurs after uncontrolled growth of cells in the breast, leukemia is cancer of the blood cells while lymphoma is cancer that affects the immune system.
The other health complications Karuhanga reveals include asthma, allergies, mental disorders resulting from neurological damage, a disorder of the nervous system, birth defects in babies, diabetes (a condition where one’s blood sugar levels are high), among others.
In order to limit the intake of foodstuffs having chemicals, Karuhanga advises individuals to try as much as possible to look out for organic foods (those that have not been sprayed with fertilisers or pesticides) .
A July 2017 World Health Organisation (WHO) article titled “Pesticide residues in food” reveals that there are more than 1,000 pesticides used around the world to ensure food is neither damaged or destroyed by pests. Each pesticide has different properties and toxicological effects.
Pesticides are potentially toxic to humans and can have both acute and chronic health effects, depending on the quantity and ways in which a person is exposed.
Some of the older, cheaper pesticides can remain for years in soil and water. These chemicals have been banned from agricultural use in developed countries, but are still used in many developing countries.
The WHO article cites an example of older, cheaper pesticides such as dichlorodiphenyltrichloroethane (DDT) and lindane that can remain in soil and water for many years after use. These chemicals have been banned by countries who signed the 2001 Stockholm Convention- an international treaty that aims to eliminate or restrict the production and use of persistent organic pollutants.