Friday, May 13, 2011

Kiwifruit dumped

It's been a mixed year for New Zealand kiwifruit growers.  Earlier in the season, some vines were found to have been infected by Pseudomonas syringae pv actinidiae (Psa) - a bacterial disease first identified in Japan about 25 years ago.  The Asian strain causes leaf spotting and some die-back of vines, though it is far less savage than the Italian strain that has also been found in one area.

In the last week, 100,000 trays of kiwifruit have been withdrawn from the market (some had already been shipped and will be intercepted) and will be destroyed.  It appears that a worker on a harvesting gang has been diagnosed with typhoid, picked up overseas before arrival in New Zealand.  Since it is not possible to isolate the specific fruit handled by the worker, all the fruit picked by that gang has been withdrawn.

The risk of infection being carried on the fruit is very low, but Zespri, the main marketer of New Zealand's $1.5 billion kiwifruit export industry, has been cautious and manned up, taking the pro-active response to prevent any possible disease risk for consumers.  This action is in stark contrast to those of some overseas companies that have attempted to conceal the potential of their products to cause harm to consumers.

The value of the withdrawn fruit is around $800,000 and represents less than 0.1% of this year's expected kiwifruit exports.  However, the unfortunate growers may not be insured, so this will be a serious loss to some orchardists.

Tyhpoid is caused by Salmonella enterica enterica, serovar Typhi, a bacterium that infects the intestine, resulting in damage to the intestine and fever.  Resultant diarrhoea can lead to transmission of the bacteria to other people and the environment.

The disease was named from the spike in infections observed after severe typhoons.  The contaminated water and poor sanitary conditions that followed the typhoons provided the conditions for increased numbers of infections.

  Mary Mallon was an itinerant cook, having arrived in America around 1874 from Ireland.  She became a domestic servant and eventually a cook in New York.  Though she appeared healthy, between 1900 and 1907, Mary had seven cooking jobs where 22 people  became ill and one died of typhoid.  After an investigation, Mary was taken by force and held against her will without trial.  This occurred at a time when the symptomless carrier state was unknown, so the investigation was quite innovative.  Mary was effectively imprisoned under sections 1169 and 1170 of the Greater New York Charter and lived alone in a cottage on North Brother island.

After her release, Mary eventually went back to cooking and this time was sent to the island for a period of 23 years, which ended only when she had a stroke.  She died six years later.

Mary was then and is still known as Typhoid Mary.

If you want to read more about Mary Mallon, go to Jennifer Rosenberg's 20th Century History page:

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