A new sterilisation method for fruit and vegetables has been developed, which quite literally sucks the life out of bugs. This method could be used in place ozone-depleting chemicals, like methyl bromide, which are currently used to sterilise fresh produce.
The technique, called metabolic stress disinfection (MSDD), was developed by Manuel Lagunas-Solar and his team at University of California, Davis (Journal of the Science of Food and Agriculture DOI 10.1002/jsfa2538).
Tim Essert, the Principle Electronics Engineer on the project, explains that MSDD works by subjecting insects on fruit and vegetables to alternating vacuum and carbon dioxide. This effectively suffocates organisms because they require oxygen to live. Ethanol gas is also used to kill fungi and bacteria.
The technique could replace the use of post harvest pesticides, and may complete the phasing out of ozone depleting methyl bromide. In 1997 160 governments promised to phase out its use by 2005 as part of the Montreal Protocol, but some exceptions were granted for the food and farming industries.
“The initial hardware cost of an MSDD system is higher than methyl bromide, but the cost of chemicals is much cheaper, so that eventually it would pay for itself”, Essert told Chemistry & Industry. Around $20 – $40 worth of methyl bromide is needed to fumigate one pallet of fruit, whereas Carbon Dioxide and Ethanol used to treat with MSDD, assuming no recovery, would cost about $10.00.
MSDD also has additional benefits to the environment, as the gasses can be recovered and recycled.