Fruits and vegetables are an indispensable source of food in the diet of Chinese residents, and pesticides play a key role in ensuring the efficiency of fruit and vegetable production. With the advancement of living standards and scientific and technological means, the issue of pesticide residues and their removal in fruits and vegetables has attracted much attention.

Fruits and vegetables are an indispensable source of food in the diet of Chinese residents, and pesticides play a key role in ensuring the efficiency of fruit and vegetable production. With the advancement of living standards and scientific and technological means, the issue of pesticide residues and their removal in fruits and vegetables has attracted much attention.

Basic Status of Pesticide Residues in Fruits and Vegetables

Although the use of pesticides in fruits and vegetables has been decreasing year by year, pesticide residues are affected by various factors, such as the quality and formulation of pesticides, the amount used, the period of use, the method of use, weather conditions, and the type of fruits and vegetables.

According to the data shown in Figure 1 as of February 2024, there are a total of 46348 registered agricultural pesticides on the China Pesticide Information Network, including 19047 insecticides, 11988 fungicides, 12797 herbicides, and 1558 plant growth regulators. With the passage of time, the types of pesticides will continue to increase.

Researchers collected 115 commercially available strawberry samples in Taizhou City from 2017 to 2021, and tested them for pesticide residues. The detection rate was 93.90%, and the exceedance rate was 2.61%; In 2021, a risk assessment analysis was conducted on 76 pesticide residues in 56 randomly sampled vegetable samples from 10 major categories in Zhongshan City. A total of 1353 vegetable samples were tested, and 51 pesticides were detected. The pesticide residue detection rate was 56.98%, and the exceedance rate was 3.62%.

The above sampling of fruits and vegetables sold in the market shows that the fruits and vegetables currently on sale are generally contaminated with varying degrees of pesticide residues, and the problem of exceeding standards is frequent. Although the risk of dietary intake is relatively small, efficient fruit and vegetable cleaning methods are crucial to ensuring the quality and safety of fruits and vegetables.

Research progress on cleaning methods and cleaning efficiency of agricultural residues in fruits and vegetables

Cleaning is a common step in food processing to remove agricultural residues from fruits and vegetables. At present, the commonly used method for removing pesticide residues from fruits and vegetables is through soaking and cleaning with different liquids, which has the advantage of being simple and fast, but the removal effect on pesticide residues is relatively low. With the continuous development of food industry technology, the current methods for removing agricultural residues from fruits and vegetables (as shown in Figure 2) include ultrasonic cleaning, ozone cleaning, non thermal plasma cleaning, electrolytic water cleaning, and pulsed electric field cleaning. Due to practicality and feasibility analysis, we will only discuss the first four methods.

① Soaking and cleaning method

Traditional soaking and cleaning methods typically use tap water, fruit and vegetable cleaning agents, diluted salt water, alkaline water, warm water, and rice washing water to soak and rinse fruits and vegetables before processing or consuming them directly. Using sodium carbonate, acetic acid, sodium chloride, and tap water to remove four types of pesticide residues on the surface of oranges: avermectin, difluorouracil, imidacloprid, and methyl thiophanate. The results showed that sodium carbonate (10 mg/mL) solution was the most effective method for removing pesticide residues on the surface of apples, followed by acetic acid (8.00%), sodium chloride (10.00%), and tap water. Using tap water, acetic acid, and citric acid to clean three pesticide residues in chili peppers: imidacloprid, chlorpyrifos, and ethyl formate hydrochloride. The results showed that soaking chili peppers in 5 L of citric acid solution (9.00%) at a temperature of 20 ℃ for 5 minutes had the best pesticide residue removal effect. However, although traditional soaking and cleaning methods can remove pesticide residues on the surface of fruits and vegetables to a certain extent, their effectiveness is not ideal. In addition, this method may result in some cleaning agents remaining on the surface of fruits and vegetables, posing potential risks to human health, including the potential impact on the environment, especially when cleaning liquids are discharged, which may contaminate water sources.

② Ultrasonic cleaning method

At present, ultrasonic cleaning method has been widely used in the food industry to remove agricultural residues from fruits and vegetables (Table 1). The ultrasonic cleaning method can effectively remove common pesticide residues in fruits and vegetables such as Chinese cabbage, spinach, grape leaves, and bok choy.

Ultrasonic processors do have a certain ability to remove pesticide residues from fruits and vegetables, but there are differences in removal rates. This mainly depends on the surface characteristics of fruits and vegetables, the physicochemical properties of pesticides, as well as various factors such as the frequency, power, and working time of ultrasound. However, higher ultrasound frequencies and powers can also cause damage to the nutritional content and surface of fruits and vegetables, and have adverse effects. This may be because the power and frequency of ultrasound are mechanical energy, which can cause damage to Chinese cabbage. Overall, when using ultrasonic treatment, it is necessary to consider the issue of maintaining the quality of fruits and vegetables while maximizing the removal of pesticide residues.

③ Ozone cleaning method

Ozone is commonly used in the food industry as a common method for removing pesticide residues (Table 2). Ozone cleaning can be used to remove common pesticide residues in fruits and vegetables such as strawberries, cabbage, apples, celery, bok choy, cowpeas, and green peppers. Using ozone microbubbles of different concentrations to treat three common pesticide residues in strawberries, cherries, and apricots: avermectin benzoate, azoxystrobin, and epoxiconazole. The results showed that soaking three types of fruits in micro bubble water containing 8.9-10.2 μ mol/L ozone for 18 minutes had the best effect, and the highest removal rate of pesticide residues could reach 70.00%. It is worth noting that after ozone microbubble treatment, the Vc content in fruits remained basically unchanged. And it has been proven that ozone microbubble treatment, as a pollution-free method for removing pesticide residues on fruits, can improve the effectiveness of food safety.

Although high concentration ozone has a good effect on the removal of agricultural residues, studies have shown that ozone treatment may affect other beneficial organic compounds in fruits and vegetables, such as ascorbic acid, phenols, lycopene, and flavonoids. In addition, other parameters such as ozone concentration, application method, and fruit and vegetable variety can affect the effect of ozone gas induced polyphenol biosynthesis. In addition, excessive ozone concentration should also be noted as it may have an impact on human health.

④ Non thermal plasma cleaning method

Plasma is the fourth state of matter besides solids, liquids, and gases. It is composed of ionized conductive gases, including electron ions, excited atoms or molecules, ground state atoms or molecules, and photons. According to the temperature of plasma, it can be divided into high-temperature plasma and low-temperature plasma, while low-temperature plasma can be divided into thermal plasma and non thermal plasma. Due to the fact that the electron temperature of non thermal plasma is much higher than the gas temperature and cannot reach thermodynamic temperature equilibrium, it is also called non-equilibrium plasma. Currently, non thermal plasma is one of the emerging physical technologies used in the food industry to remove pesticide residues. Non thermal plasma can effectively remove pesticide residues from mangoes, grapes, blueberries, lettuce, apples, and goji berries (Table 3).

Non thermal plasma technology can remove a large amount of pesticide residues in a short period of time, and this technology does not require the use of harmful chemicals, making it very safe and efficient. It does not damage the taste and nutrition of the food itself, and processed fruits and vegetables are more conducive to preservation and transportation. However, non thermal plasma technology also has some drawbacks, such as high initial investment, such as the cost of gas used for plasma generation, which greatly increases overall costs due to the use of inert gas operation, technical challenges involved in expanding process scale, low plasma penetration, and the problem of how to accurately control the chemical reactions of gas plasma reactions. Further research and exploration are needed.

⑤ Electrolytic water cleaning method

After softening or purifying the tap water, it enters the electrolytic cell for electrolysis. On the anode side, H ₂ O is electrolyzed to produce O ₂ and H+, forming acidic electrolyzed water (AEW). On the cathode side, H ₂ O is electrolyzed to produce H ₂ and OH -, forming alkaline electrolyzed water (AlEW). Due to the high biological safety of electrolyzed water, experts and scholars at home and abroad have found no significant changes in various indicators of the experimental subjects through skin irritation and cytotoxicity experiments on mice, mammals, and human volunteers. In addition, ultra alkaline/strong alkaline electrolyzed ionized water has the characteristics of efficient removal of agricultural residues on the surface of fruits and vegetables, ensuring the quality of fruits and vegetables, and being harmless to the environment. And after sterilization, it can be converted into ordinary water without causing adverse effects on water sources and air. Its production method is safe and simple, and has gradually been applied in fields such as food industry, medicine, agricultural planting, and animal husbandry.

Electrolytic water can be used to remove pesticide residues from cabbage, broccoli, bell pepper, kumquat, and lettuce, as shown in Table 4.

In summary, the research progress and analysis on the cleaning methods and efficiency of agricultural residues in fruits and vegetables shows that different methods for removing agricultural residues have their own advantages and disadvantages. Ultrasonic cleaning is highly favored due to its environmentally friendly, efficient, and energy-saving characteristics. However, ultrasonic cleaning can cause certain damage to fruits and vegetables during use, and precise adjustment of parameters such as frequency, power, and time is required to ensure the stability and controllability of the cleaning effect. On the other hand, ozone has shown outstanding performance in removing pesticide residues and has a good effect. However, it should be noted that high concentrations of ozone treatment may have adverse effects on some nutrients in fruits and vegetables, such as Vc, and pose potential risks to human health to a certain extent. For non thermal plasma treatment technology, although it has a certain removal effect, most research is currently conducted on a laboratory scale. Therefore, more research is needed to evaluate the safety of plasma systems. Electrolytic ionized water (electrolytic alkaline water, electrolytic acidic water), as a new type of environmentally friendly cleaning method, has the characteristics of non toxicity and no residue, and has been involved in many fields.

In recent years, electrolytic water technology has sparked a wave of application in fields such as food industry cleaning and deep processing of agricultural products, thanks to its green, environmentally friendly, efficient, and safe characteristics. As a brand that has been deeply involved in the field of electrolyzed water cleaning for 20 years, Fangxin's intelligent electrolyzed water equipment has passed third-party testing and certification by professional institutions, and its various indicators have stood the test of time. Smart IoT promotes industry development through technological innovation: its electrolyzed slightly acidic hypochlorous acid water and ultra alkaline electrolyzed water have a sterilization rate of up to 99.9999%, and the efficiency of pesticide residue degradation is much higher than traditional processes, with no chemical additives or harmful substance residues throughout the process, forming an environmentally friendly cleaning mode of "water to clean".

Fangxin alkaline electrolysis water pesticide residue detection report

Fang Xin Micro Acidic Hypochloric Acid Water Sterilization Test Report

At present, Fangxin electrolytic water equipment has been used in production chain cleaning, disinfection and sterilization, sterile water and reclaimed water reuse of Jinzai, Yican and other food enterprises We serve fruit and vegetable purification terminals for multiple enterprises across the country, and have entered markets in Southeast Asia, America, and other countries. We have established a multi scenario application system in medical disinfection, central kitchen pre made meals, school institutions, and other scenarios. Relying on stable equipment performance and a global intelligent operation and maintenance system, Fangxin Equipment maintains a steady market growth trend. Currently, it has a high market awareness in the field of electrolytic water equipment in China and provides green and clean solutions for various types of institutions.

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Note: The experimental content of this article is from "Modern Food Technology" and "Research progress on the removal effect of pesticide residues in fruits and vegetables by different cleaning methods". The content of this article is only for the purpose of conveying more information and is for reference only. If there is any infringement of relevant content, please notify us.