Pesticide Residues in Peppers: History
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Pesticides are chemicals that are used to control pests such as insects, fungi, and weeds. Pesticide residues can remain on crops after application. Peppers are popular and versatile foods that are valued for their flavor, nutrition, and medicinal properties. The consumption of raw or fresh peppers (bell and chili) can have important health benefits due to their high levels of vitamins, minerals, and antioxidants. Therefore, it is crucial to consider factors such as pesticide use and preparation methods to fully realize these benefits. 

  • pepper
  • pesticide residue
  • monitoring

1. Introduction

Peppers are an important part of many diets worldwide due to their nutritional value. Peppers are a rich source of vitamins and minerals, including vitamins C and A and potassium [1]. They are also high in antioxidants and phytochemicals [2], which are associated with many health benefits, including boosting the immune system [3], maintaining healthy skin and eyesight [4], reducing the risk of chronic diseases, such as cancer and cardiovascular disease [3], and managing blood sugar levels [4]. Furthermore, peppers have a distinctive flavor [5] and can be used in various dishes, including salads, sandwiches, and cooked dishes. They can also add color and flavor to various dishes, including soups, stews, and stir-fries. Moreover, peppers are an important part of the cuisine and culture of many countries worldwide. They are often key ingredients in traditional dishes, such as curries, stews, and sauces. In the Republic of Korea, chili peppers are frequently used in traditional cuisines, such as kimchi [6]. They are available in various forms, including fresh, cooked, dried powder, processed, and frozen, and there are various types of pepper, including sweet peppers and hot peppers. Some common examples include bell peppers, banana peppers, Cubanelle peppers, Jalapeño peppers, Habanero peppers, and Serrano peppers [7,8]. Peppers are also an important source of income for many small farmers, particularly in developing countries where they are grown for local consumption and export and contribute to the economic development of communities. According to the Food and Agriculture Organization of the United Nations (FAO), the worldwide production of pepper was approximately 540,000 metric tons in 2020. The top five pepper-producing countries worldwide are listed in the following order: Vietnam, Indonesia, Brazil, India, and Malaysia [9].
Pepper leaves can be used as an ingredient in a type of Korean dish called Namul Namul refers to dishes made with seasoned vegetables and herbs that serve as side dishes or as part of a larger meal [10]. In general, they are not typically consumed as food. However, they can be used in traditional medicine in some cultures. Pepper leaves have been used in traditional remedies to treat a range of ailments, including digestive disorders and respiratory diseases. However, pepper leaves have not been extensively studied for medicinal purposes, and their safety and effectiveness have not yet been established.
The quantity and safety of agricultural products are intimately linked to public health, social stability, and sustainable development. Therefore, this topic has gained increasing concern among the general public, health authorities, and the scientific community [11]. The World Health Organization (WHO) states that fruits and vegetables are crucial to a healthy diet. Reduced consumption of fruits and vegetables could correlate with poor health and a higher risk of noncommunicable diseases.

2. Effect of Household Processing on Pesticide Residue Levels in Peppers

Several household processes can be used to reduce pesticides in fresh peppers, including washing and blanching. These processes can effectively remove or reduce the levels of pesticides on the surface of peppers, but they may not completely eliminate all residues. For instance, washing peppers thoroughly using running water can effectively remove surface contaminants, including pesticides, but it will not remove all pesticides, particularly those that have been absorbed into the pepper tissue [13]. Blanching is a process in which peppers are briefly boiled in water or steam and then cooled in ice water. This process can help loosen the pepper’s skin, making it easier to remove. It can also help to reduce the levels of pesticides on the surface of the pepper, as some pesticides may be removed during the boiling process [80]. Again, blanching may not be able to remove all pesticides, particularly those that have been absorbed into the pepper tissue. In this context, Kim et al. [80] evaluated the effects of various household processes, such as washing, blanching, frying, and drying, under different conditions (water volume, blanching time, and temperature) on residual pesticide concentrations. Both washing and blanching (in combination with high water volume and processing time) significantly reduced pesticide residue levels in the leaves and fruit of hot pepper compared with other processes [80]. It is worth considering other conditions/factors, such as selecting peppers that are grown using sustainable and organic practices to further reduce the levels of pesticides in peppers.

3. Dissipation Patterns and Preharvest Intervals in Peppers

Pesticides that are applied to peppers can be absorbed by the plant while also being present on the surface of the pepper fruit. The rate at which pesticides dissipate or break down can vary depending on several factors, including the type of pesticide, the application rate, the weather, and the application method. Generally, most pesticides will dissipate more quickly in warm, humid conditions and more slowly in cool, dry conditions. Pesticides applied to the surface of the pepper fruit may dissipate more quickly than those absorbed by the plant, as they are more exposed to the environment.
The dissipation behavior of pesticide residues in peppers has been investigated [81,82,83,84,85,86,87]. For instance, Liu et al. [85] reported that the t1/2 values of metalaxyl in peppers were 3.2–3.9 days at three experimental locations in China. At harvest, pepper samples were found to contain metalaxyl and cymoxanil levels that were well below the MRLs of the EU following the recommended dosage and an interval of 21 days after the last application.
The environmental fate of field-applied synthetic pesticides has been under investigation for several years. Endosulfan 3 EC, a mixture of α- and β-stereoisomers, was sprayed on field-grown pepper at the recommended rate of 0.44 kg of active ingredients per acre. Endosulfan sulfate is the major metabolite of endosulfan sulfite, and the β-isomers are relatively more persistent than the α-isomers. In pepper, the α-isomer, which is more toxic to mammals, dissipated faster (t1/2 = 1.22 day) than the less toxic β-isomer (t1/2 = 3.0 day). These results confirm the greater loss of the α-isomer than the β-isomer, which can ultimately impact endosulfan dissipation in the environment [82].
The degradation behavior of flonicamid and its metabolites, 4-(trifluoromethyl)nicotinic acid (TFNA) and N-(4-trifluoromethylnicotinoyl) glycine (TFNG), was evaluated in red bell peppers over 90 days under greenhouse conditions, including high temperature, low and high humidity, and in a vinyl house covered with a high-density polyethylene light shade covering film (35% and 75%). For safety reasons, the authors concluded that red bell peppers should be grown under greenhouse conditions because solar radiation increases the rate of flonicamid degradation into its metabolites [88].
It is also possible to reduce the need for pesticides by using integrated pest management techniques, such as introducing natural predators of pests or using physical barriers to prevent pests from accessing plants.
PHIs are the minimum amount of time that must pass between the application of a pesticide and the harvest of a crop. The purpose of PHIs is to allow pesticides to break down or dissipate in the environment and on the surface of the crop to levels that are considered safe for consumption. PHIs vary depending on the specific pesticide used, the type of crop, and the application method. It is important to follow the label instructions for a particular pesticide, as these will include the recommended PHI for the crop in question to ensure that the peppers are safe to consume. It is also worth noting that some pesticides may not be approved for peppers, which means there would be no recommended PHI. It is important to use pesticides only as directed and to follow all label instructions to help ensure the safety of the crop and to protect human health.

4. Dietary Risk Assessment

The dietary risk assessment of pesticide residues in peppers is an important task that helps determine the potential health effects of consuming peppers treated with pesticides. This assessment typically involves several steps, including:
  • Identify the pesticides that are commonly used on peppers, as well as their maximum residue levels (MRLs).
  • Collect data on the levels of pesticide residues found in peppers sold on the market.
  • Evaluate the potential health risks posed by the consumption of peppers with pesticide residues based on the levels found and the MRLs.
Once the data are collected, they can be used to estimate the average daily intake of each pesticide for different population groups. This can be performed by using data on pepper consumption patterns and the levels of pesticide residues found in peppers. Next, the potential health risks posed by the consumption of peppers with pesticide residues can be evaluated by comparing the estimated daily intake of each pesticide with the appropriate reference doses (RfDs), such as acceptable daily intakes (ADIs) or acute reference doses (ARfDs) [30,89]. These values are established by regulatory agencies, such as the US Environmental Protection Agency (EPA), as a safe level of exposure for the general population. It is worth mentioning that to have a comprehensive view of the impact of pesticide residues in peppers on human health, it is crucial to look not only at the impact of a single pesticide but also at the combined effect of different pesticides that may be present in the pepper [90,91,92]. While the impact of individual pesticides on human health has been extensively studied, the combined effect of multiple pesticides is less understood. However, there is growing evidence to suggest that exposure to multiple pesticides can have additive or synergistic effects on human health and that the cumulative effect of these residues may be greater than the effect of individual pesticides alone. Therefore, it is important to consider the potential combined impact of multiple pesticide residues when evaluating the health risks associated with consuming peppers or other fruits and vegetables. In addition, the levels of the detected pesticide in peppers can be tolerated and do not pose a serious health problem to the community [30,31]. However, it is worth noting that some people may be more sensitive to pesticides than others, such as pregnant women and children [93]. Additionally, long-term exposure to low levels of pesticides may also pose health risks [94]. It is also important to note that the risk assessment process may vary by country, as different countries have different regulations for pesticides, different exposure scenarios, and different methods for assessing risks. It is worth mentioning that regulatory agencies continuously monitor the situation and update their guidelines and regulations as necessary.

This entry is adapted from the peer-reviewed paper 10.3390/foods12050970

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