Researchers from Nanjing Agricultural University say that vegetables watered with fresh manure within 7 days are generally heavily contaminated. In autumn and winter, spinach and carrots are the most contaminated, followed by pakchoi. In spring and summer, white radishes are the most contaminated.
Citizens who buy vegetables from markets often prefer those from suburban farmers, as these vegetables are mostly irrigated with manure and have no pesticide residues. A new study by institutions such as Nanjing Agricultural University and Jiangsu Academy of Agricultural Sciences shows that vegetables irrigated with manure can be contaminated by pathogenic microorganisms, but the contamination is significantly reduced after being rinsed with tap water.
Researchers mainly tested vegetables such as pakchoi, radish, lettuce, and celery. The test results found that the closer to the time of fertilization, the more Escherichia coli on the vegetable surface, but the number of Escherichia coli inside the vegetables was not affected.
Researchers from Nanjing Agricultural University say that vegetables watered with fresh manure within 7 days are generally heavily contaminated. In autumn and winter, spinach and carrots are the most contaminated, followed by pakchoi, while in spring and summer, white radishes are the most contaminated. Common methods used by citizens, such as soaking and rinsing with tap water, are somewhat effective in removing Escherichia coli from the surface of vegetables, with rinsing being the most effective.
In addition, the best method to kill pathogenic bacteria on vegetables is to soak them in boiling water. Boiling water treatment for 15 seconds can significantly reduce the number of Escherichia coli on the vegetable surface. For leafy vegetables, soaking in boiling water for 30 to 45 seconds can basically kill the Escherichia coli inside. For radishes, soaking in boiling water for over 60 seconds can completely kill the Escherichia coli inside.