Limes are classified as a weapon in the UK?

What is next? Lime registration? From the UK Daily Mail:

A chef was stunned to find she was almost banned from buying two limes from a supermarket - because they could be classed as a weapon.
Marisa Zoccolan, 31, popped into the new Asda supermarket close to her home in Wallsend, North Tyneside, to pick up some groceries, including the citrus fruits.
But when she tried to pay for them at the self-service checkout, the message 'amount exceeded, authorisation required' flashed up.
An assistant then came over and told her that more than one lime was deemed a weapon - because the citric acid could be squirted in someone's eye.
Marisa, a self-employed caterer said: 'I thought they were taking the pip, but the assistant told me the same applied to lemons. . . .