When is it safe to eat after insecticide spraying? (Factors)
In this brief guide, we will answer the question “When is it safe to eat after insecticide spraying”. We will also talk about how to reduce insecticide residues in your food and will discuss the most common types of insecticide.
When is it safe to eat after insecticide spraying?
The answer to that question is highly dependable on the type of insecticide used and the category of food it is being used on. Some insecticides have no waiting period and the product can be picked up on the same day of application. Other insecticides have a prescribed number of days that need to elapse between the last application and harvest when the product is safe to eat. (1)
What are the factors that affect the duration of insecticide residues?
Several factors can affect the duration of insecticide residues. This is measured by the preharvest interval (PHI) and the half-life of an insecticide. The ability to resist degradation (persistence) under various conditions is measured as the half-life of the insecticide.
Numerous factors affect the extent of pesticide absorbance, penetration and degradation and differ from one category of food to another. The “half-life” is the time required for half of the insecticide to break down/disappear. Preharvest interval (PHI) is the minimum amount of time between the last application of a pesticide and when the crop can be harvested.
The PHI of an insecticide can range from several hours to several days, the half-life can range from hours or days to years for more persistent ones. The rate at which insecticides are moved and dissipated is closely related to the physico-chemical parameters of the insecticide itself and surrounding environmental conditions. (2, 3)
Can insecticides be harmful to your health?
Yes, All insecticides are poisonous and must be used with caution. These harmful substances can remain in or on food, putting humans at risk of specific illnesses. While pesticides bring benefits to agriculture, the enduring residues present in various environmental components increase the danger for consumers, mainly through consuming contaminated food.
To combat the health hazards linked to pesticide residues, many countries have established Maximum Residue Limits (MRLs) for different agricultural goods. Determining the dietary exposure to pesticides includes considering factors like the average daily food consumption per person, the typical weight of an adult, and the concentration of pesticide residues found in the food. (4)
How to reduce insecticide residues in food?
The reduction of pesticide residues in fruits and vegetables can be accomplished through various food processing methods. These techniques are applicable for both commercial and home food processing. They include practices such as washing, peeling, blanching, cooking, pureeing, frying, roasting, and boiling.
Washing effectively reduces loosely attached surface pesticides while peeling eliminates even those residues that have penetrated the outer layers of the produce.
The efficiency of washing depends on the age of pesticide application. Residues are easier to remove shortly after spraying compared to a week later. In processes like baking, boiling, canning, and juicing, both reduction and increase in pesticide residue levels may occur.
Cooking typically involves processes such as volatilization, hydrolysis, and thermal breakdown. It’s important to note that open systems during cooking lead to water loss through evaporation, potentially concentrating pesticide residues if they are not adequately destroyed by the heat. (5)
What are the different types of insecticides and their persistence?
Insecticides encompass a diverse array of chemicals, belonging to different classes, and they exhibit toxicity not only to insects but also to vertebrate mammals, albeit through distinct mechanisms of action. Some of the most prevalent classes of insecticides include:
- Organophosphates (OP) and Carbamates (CM): These are often grouped as anticholinesterase agents because they both target the acetylcholinesterase (AChE) enzyme. One of their advantages is the minimal residue persistence in the environment and mammalian systems. Furthermore, insects tend to develop less resistance to these insecticides compared to organochlorines, making them widely used across the globe. (6)
- Chlorinated hydrocarbons or organochlorines: They are classified into three main groups: dichlorodiphenylethanes, hexachlorocyclohexanes, and chlorinated cyclodienes. Examples of these groups include DDT, mirex and toxaphene, aldrin and dieldrin. However, due to their long-lasting presence in the environment and biological systems, most insecticides belonging to this category have been phased out. (6)
- Pyrethrins and synthetic pyrethroids: This category is widely used in agriculture, public and animal health, as well as residential settings around the world. These insecticides are known for their quick decomposition when exposed to light and air. To further enhance effectiveness, synthetic derivatives called pyrethroids were developed. (6)
- Amitraz: Amitraz belongs to the formamidine pesticide family, specifically a triazapentadiene compound. This compound acts as a powerful insecticide and acaricide, making it widely used in agriculture, horticulture, and veterinary medicine. (6)
- Neonicotinoids: Neonicotinoids are a newer class of insecticides. This category includes compounds like imidacloprid, acetamiprid, thiacloprid, dinotefuran, nitenpyram, thiamethoxam, and clothianidin. They are widely used in agriculture and veterinary medicine due to their specific action against insects. Moreover, they pose relatively low risks to non-target mammals and the environment. (6)
- Rotenone: Rotenona is a naturally occurring insecticide found in plants like Derris, Lonchocarpus, Tephrosia, and Mundulea species. It possesses a broad range of insecticidal, acaricidal, and pesticidal properties. While considered safe when used correctly, higher doses can be toxic to humans, animals, and fish. (6)
How insecticide intoxication can be detected?
In many cases, when it comes to determining exposure levels, the presence of insecticide residues or their byproducts can be detected in bodily fluids like urine, blood serum, plasma, and milk. Additionally, changes in behavior, biochemistry, molecular processes, and histopathological outcomes are used as biomarkers of effects.
The majority of insecticides possess neurotoxic properties that affect both targeted insects and non-targeted mammalian species, including humans. Additionally, wildlife and aquatic organisms are also impacted by these neurotoxic properties.
While the toxicity level in non-targeted species is generally lower compared to insects, these insecticides can still have detrimental effects on various organs and systems within the body. (6)
In this brief article, we answered the question “How long after spraying insecticide is it safe to eat?” We also talked about how to reduce insecticide residues in your food and discussed the most common types of insecticides.
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Health Canada. Understanding Preharvest Intervals for Pesticides. [homepage on the internet] The official website of the Government of Canada; 2021.
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KEIKOTLHAILE, Boitshepo Miriam; SPANOGHE, Pieter; STEURBAUT, Walter. Effects of food processing on pesticide residues in fruits and vegetables: A meta-analysis approach. Food and Chemical Toxicology, v. 48, n. 1, p. 1-6, 2010.
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