Pesticide on fruits

Discussion in 'Chemistry' started by timojin, Nov 9, 2017.

  1. timojin Valued Senior Member

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    How do you remove remove pesticide on apple
     
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  3. geordief Registered Senior Member

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    I have heard quite recently that baking soda is the most effective.

    You can also peel the skin.
     
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  5. timojin Valued Senior Member

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    Since the pesticide is an aromatic compound would washing with detergent emulsify it ?
     
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  7. geordief Registered Senior Member

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    Sorry I am not a chemist.That was just a news report that I heard in the past week or so


    They tested various methods (including quite possibly detergents) but found baking soda to be most efficient

    The pesticide was also found beneath the skin and so it might also be necessary
    to peel it (a shame)
     
  8. exchemist Valued Senior Member

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    First of all, is there a problem?

    I've had a quick look on the web but can't find any data giving levels of pesticide residue found on fruit, only some media reports of a US study which said residues were detected. This gives no idea of what pesticides were detected or how much residue in relation to current safety limits, which is what one would need to make any kind of assessment of risk. As modern analytical techniques are often highly sensitive, it is conceivable they they detected ppb levels when the safe limit is ppm.

    From the little practical advice I could find, it appears that simply washing fruit is all you need to do, which we all do anyway, I imagine.

    But if anyone can find a link to some actual facts, I'd be interested.
     
  9. geordief Registered Senior Member

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    http://www.channelnewsasia.com/news...est-for-washing-pesticides-off-apples-9387520

    As I said ,I just heard this (on the radio or TV) but it is definitely the same story-and very recent.
     
  10. exchemist Valued Senior Member

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    Aha thanks. This seems to confirm the levels found were well below the levels thought to pose any risk.

    I'm intrigued that sodium bicarbonate (NaHCO3) reacts with these pesticides. I have not yet looked up what they are chemically. Sodium bicarb is a weak base. (You mix it with tartaric acid to make sherbet).
     
  11. iceaura Valued Senior Member

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    My guess would be it handles the carrier, the glue-stuff that sticks the pesticide itself it to the apple. Rain is a weak acid, no?

    Most of the safety regulations and residue-detection reports and so forth pay little attention to the various auxiliary compounds and carrier matrix involved - in much larger quantities, btw.
     
  12. exchemist Valued Senior Member

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    Could be. When I looked up thiabendazole I saw it was actually used as a treatment for human intestinal worms. So presumably it can't be that dangerous to health!
     
  13. timojin Valued Senior Member

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    I just come across this

    Effectiveness of Commercial and Homemade Washing Agents in Removing Pesticide Residues on and in Apples
    Tianxi Yang

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    , Jeffery Doherty§, Bin Zhao

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    , Amanda J. Kinchla, John M. Clark§, and Lili He*

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    †Department of Food Science and ‡Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, Massachusetts 01003, United States
    § Massachusetts Pesticide Analysis Laboratory, Amherst, Massachusetts 01003, United States
    J. Agric. Food Chem., 2017, 65 (44), pp 9744–9752
    DOI: 10.1021/acs.jafc.7b03118
    Publication Date (Web): October 25, 2017
    Copyright © 2017 American Chemical Society
    *Telephone: +1-413-545-5847. E-mail: lilihe@foodsci.umass.edu.
    Abstract

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    Removal of pesticide residues from fresh produce is important to reduce pesticide exposure to humans. This study investigated the effectiveness of commercial and homemade washing agents in the removal of surface and internalized pesticide residues from apples. Surface-enhanced Raman scattering (SERS) mapping and liquid chromatography tandem mass spectrometry (LC–MS/MS) methods were used to determine the effectiveness of different washing agents in removing pesticide residues. Surface pesticide residues were most effectively removed by sodium bicarbonate (baking soda, NaHCO3) solution when compared to either tap water or Clorox bleach. Using a 10 mg/mL NaHCO3 washing solution, it took 12 and 15 min to completely remove thiabendazole or phosmet surface residues, respectively, following a 24 h exposure to these pesticides, which were applied at a concentration of 125 ng/cm2. LC–MS/MS results showed, however, that 20% of applied thiabendazole and 4.4% of applied phosmet had penetrated into the apples following the 24 h exposure. Thiabendazole, a systemic pesticide, penetrated 4-fold deeper into the apple peel than did phosmet, a non-systemic pesticide, which led to more thiabendazole residues inside the apples, which could not be washed away using the NaHCO3 washing solution. This study gives us the information that the standard postharvest washing method using Clorox bleach solution for 2 min is not an effective means to completely remove pesticide residues on the surface of apples. The NaHCO3 method is more effective in removing surface pesticide residues on apples. In the presence of NaHCO3, thiabendazole and phosmet can degrade, which assists the physical removal force of washing. However, the NaHCO3 method was not completely effective in removing residues that have penetrated into the apple peel. The overall effectiveness of the method to remove all pesticide residues diminished as pesticides penetrated deeper into the fruit. In practical application, washing apples with NaHCO3 solution can reduce pesticides mostly from the surface. Peeling is more effective to remove the penetrated pesticides; however, bioactive compounds in the peels will become lost too.

     
  14. exchemist Valued Senior Member

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    Thanks, that looks like the one.
     
  15. cluelusshusbund + Public Dilemma + Valued Senior Member

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    Most apples you buy have a coat of wax added to 'em... an if you gonna try to wash pesticides off of 'em you woud first need to get the wax off.!!!
     
  16. geordief Registered Senior Member

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    Saw some last week that were so shiny I went and picked one up as it looked as if they had all been individually clingfilmed .
     

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