What Can Go Wrong with Sea Cucumbers?

YY TSANG

(CMA Testing and Certification Laboratories)

There have been media reports from time to time about counterfeit and adulterated sea cucumbers. A restaurant located in Guangzhou is recently found selling “artificial sea cucumbers”. It is reported that the fake sea cucumbers are made of algal powder, konjac powder, etc. A few appearance defects of the fake food have been observed (e.g. blocked ends, papillae of equal thickness and length, and unnatural shiny black colour).

Photo Source：on.cc, 2016

http://hk.on.cc/cn/bkn/cnt/news/20160421/bkncn-20160421092211242-0421_05011_001.html?eventsection=cn_news&eventid=402882b152f254d701531b9294a12c83

However, we can’t always affirmatively tell if a sea cucumber is real by its appearance. Superb counterfeiting technology can indeed make a fake sea cucumber look “natural”.

On the other hand, dishonest traders may substitute expensive sea cucumbers with cheaper sea cucumbers though they are real. General public and even experts cannot identify the species of a sea cucumber with the naked eye, especially dried sea cucumbers because some morphological features have been lost. Can you tell the names of sea cucumbers below?

Photo Source：FAO, 2004

http://www.fao.org/docrep/007/y5501e/y5501e0b.htm

Scientific Identification of Sea Cucumbers

There are over 40 edible species of sea cucumbers in the world. Examples include Japanese sea cucumber (high price), white teatfish from Australia (medium price) and sandfish from Middle East (low price). In order to combat food adulteration, few years ago a local university successfully employed a DNA-based technique to identify different dried seafood (including sea cucumbers) sold in Hong Kong.

Food Safety Risks of Sea Cucumbers?!

Since ancient times, sea cucumber is considered as tonic food. However, just like other foods, incidents associated with sea cucumbers have once occurred.

1)　Excessive Additives

In 2011, excessive use of caustic soda (i.e. sodium hydroxide) in sea cucumbers manufactured in the Mainland was reported. Sodium hydroxide can be used as an acidity regulator, a washing agent and/or a peeling agent in food. Moderate use of the chemical is safe for consumers. However, abuse of caustic soda in sea cucumbers shall increase food safety risk.

2) Prohibited Preservatives

During the storage and transportation of sea cucumbers, dishonest traders may illegally use carcinogenic formaldehyde to prevent sea cucumber from deterioration.

3)　Environmental Contaminants

If the marine environment for sea cucumber aquaculture is polluted, toxic substances present in seawater will accumulate inside sea cucumbers in the territory. For example, a study once found that sea cucumbers samples collected from Zhoushan in Zhejiang province of Mainland, contained excessive chromium, arsenic, mercury and lead. Moreover, persistent environmental pollutants (e.g. PAHs) were also detected.

4)　Aquaculture Drugs

During the aquaculture stage, farmers may use several chemicals (e.g. antibiotics, disinfectants, etc.). If the chemicals are excessively used or the rules of withdrawal periods are not followed, chemical residues may be found in farmed sea cucumbers.

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