Redback jumping spiders found in grapes despite all systems working

10 November 2000

There have been two confirmed findings of Redback jumping spiders (Phidippus johnsoni) in Californian table grapes this week.

 The Ministries of Agriculture and Forestry and Health are asking the public to stay on the lookout for the spiders and to contact MAF immediately they find any exotic spiders (Phone 0800 809 966). The Ministry of Health issued a warning to food retailers and consumers today.

The redback jumping spider is venomous, but its bite is not fatal. The bite can however result in swelling, tenderness and pain at the bite site, which can last for several days. Some people may also experience headaches, fever, chills, nausea, and vomiting..

Redback jumping spiders are hairy and grow to approximately 2cms. As the name implies the back is often distinctly red, with a black strip down the middle. The rest of the body is usually black.

The spiders were found in cartons of grapes in Hastings and Christchurch. Both specimens were sent to MAF's National Plant Pest Reference Laboratory near Christchurch for identification.

New Zealand imports approximately 400,000 cartons of Californian table grapes a year. These grapes go through stringent post-harvest fumigation in California prior to shipment. The United States Department of Agriculture officers have recently undertaken an audit of the required treatments on behalf of MAF and found that all treatments are being carried out in accordance with agreed standards.

After the finding of two live black widow spiders in Californian table grape cartons early last month, MAF added further inspection and audit activities to confirm that existing systems meet MAF standards. Additional inspections were done in New Zealand, with additional checks in the United States as well.

"We have in place all reasonable checks available to us. The United States audit showed there were no systems failures. However, fumigation and inspection do not give 100 percent assurance that spiders living in the grapes will be detected and killed" says Justin Downs, MAF's national adviser international operations (plant imports).

Mr Downs said methyl bromide fumigation could be used but this would leave the grapes inedible, as they would turn to mush. Furthermore methyl bromide fumigation is only 60% effective in killing spiders.

"There is an element of risk involved in importing Californian table grapes, and in all areas of trade, particularly in fresh produce. There is always the risk that something unwanted in New Zealand will make it past the border. The only way to make sure nothing makes it through our borders is to stop the trade altogether or to inspect every carton of grapes

There are 21 containers of grapes coming into New Zealand next week, each containing 1200 grape cartons. Mr Downs said it would be near impossible to inspect all the grapes in every carton.

Next week the Ministry of Health, the Department of Conservation and MAF will be jointly re-examining the current import health standard for grapes to check again whether there are any other measures that we can adopt to lower the risk of importing venomous spiders with grapes.

For further information contact:

Justin Downs, MAF's National Adviser International Operations (Plant Imports). Telephone 04 474 4119 or 021 444 988
Selina Gentry, Media Adviser. Telephone: 04-496-2483 or 025-277-5411
Gita Parsot, MAF Communications. Telephone: N/A 

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