Have you heard this one before? There are two blackcurrants, one has a high vitamin content and the other - well it doesn't.
It's hardly a rib-tickler is it?
In fact, I'm not even sure it's a joke, but the punch line has certainly got a kick to it, and has resulted in considerable embarrassment for one of the world's leading multinational companies.
GlaxoSmithKline (GSK), producer of the popular juice drink Ribena, has recently had to admit that some of its juices did not contain the levels of vitamin C that they claimed to. Why? Because of the varying nutritional content of locally sourced blackcurrants in certain countries.
Current legislation on nutrition labelling is not taking into account the effect locally sourced ingredients have on globally supplied products. As a result, consumer confidence in the products they buy is being failed.
The recent embarassment faced by GSK has served to highlight the issue of whether nutrition labelling on globally supplied products is accurately informing consumers of what they are eating and drinking.
The last few weeks have been particularly turbulent for the company, after the nutritional claims made on its Ribena labels were called into question by - of all people - a group of school children in New Zealand.
During testing performed in their class, the pupils discovered that despite Ribena's claims of being "high in Vitamin C", the drink actually contained very little.
This led to the GSK disclosing just a few weeks ago that claims being made about some Ribena products being sold in Australia may also be misleading consumers.
Just a week later however, independent testing by Singapore's Agri-Food and Veterinary Authority (AVA) found that samples of the drink being sold in the country did meet GSK's nutritional claims regarding high vitamin C content.
The reason for this discrepancy according to the AVA was simple. Samples of Ribena being sold in both Malaysia and Singapore are produced separately from the product that is available in Australia and New Zealand.
It is not geography that is the problem here, however, but the difficulties in sourcing local ingredients for a global product.
To suggest, after all, that an apple in one part of the world will have the same nutritional benefits as an apple from a different part of the world, is an unfair expectation.
And herein lies the problem for nutrition labelling. How can companies truly inform clients of a product's nutritional content when it relies on average data and not figures relating to the product in hand?
It would be unfair to simply blame GSK for this problem, as it is only one of many global companies that locally source raw ingredients for their products.
But in every case, nutrition labelling must take into account the differences between ingredients from each individual region.
In a publication released, ironically, just before GSK's recent disclosure, a report for the Food Legal Bulletin questioned the very point of the current legislation on making health claims.
"All such data irrespective of its source would be subject to being an average or mean of data accumulated over many years from many analyses," states the report.
"For some inexplicable reason, the law always assumes that this data has been derived from the same named biological source, even though this assumption is a fiction."
With nutritional content likely to vary from individual weather conditions and farmers' treatments, the report questions the effectiveness of labelling practices in accurately judging a product's nutritional value.
"Since it is mandatory by law to require that the Nutrition Information Panel accompany all food products on the label of packaged food or be available on request for the buyer of unpackaged food, what is the point of having the law exist at all?" concludes the report.
Yet legislating nutrition labelling is hugely important, particularly for companies that are keen to tap into growing consumer demand for nutritional benefits in foods and beverages.
But unless the industry and health authorities can fully substantiate what is in their products, they risk more embarrassing headlines and consumer backlash.
A weekly comment article runs across all online publications run by Decision News Media and targeting the food industry. Neil Merrett is a staff reporter for AP-Foodtechnology.com, and has written on a variety of issues for publications in both the UK and France.
If you would like to comment on this article, please e-mail Neil.Merrett'at'decisionnews.com