Wednesday, March 23, 2011

Why Some Stingray have Ammonia, Urine or Urea Smell? How to get rid of it?

Alice Law and SuiTuaPui commented about their experience with Ammonia smell in stingray at my post, Simple spicy Stingray with Butter and Masala Recipe. I have once bought a stingray that reeked of urine smell and no matter what strong spices I used, the smell is still there. There are several reasons why stingrays have urine, urea or ammonia smell. Stingray is a cartilaginous fish related to the shark. Their body and tissues are designed to be isotonic with sea water. In order to do so, stingrays and shark kidneys are designed to excrete urea into the body tissues. Therefore, when their body is in osmotic balance with sea water, they can prevent water loss from the body cells. When a stingray dies, bacteria will break down the urea compound and turn it into ammonia. This explains why stingrays that are not fresh have very strong ammonia smells. Fresh stingrays have clear bright red coloured blood and those that are not fresh would normally have darker red blood. Since ammonia is alkaline, soaking the stingray in light cooking vinegar which is acidic would neutralize it into salt and water. A possible reason for Stingrays to have urine or urea smells is very likely that they are not gutted properly. The person handling the fish might have accidentally cut the kidneys and other organs that have high urea content. The urea can leak into the flesh, thus contaminate it. Since urea is acidic, soaking the stingray in Sodium Bicarbonate (Baking soda) which is alkaline might help to rid off the urine smell. So, the questions is, how do we know the smells is from ammonia or urea? If the fish doesn’t look fresh and have a nose piercing smell that very likely it is from the ammonia. If the fish is fresh and have clear bright red blood colour, then the smell is very likely from the urea content. I was lucky to have only one bad experience with stingray with terrible odour. Whenever I buy stingray, I would smell it first and check the blood whether is clear bright red in colour. Please note that you might not see much blood in stingray cut after the fishmonger washes them. This doesn’t mean that they are not fresh. It is always good to ask the fishmonger for advice. I normally buy fish from a few fishmongers that I know are reliable and have been my regular supplier for years. This really helps a lot in ensuring that I get the best fish. Happy marketing and cooking!

19 comments:

cleffairy said...

This is one tips I can use...after all, one of the only fishes that I would willingly cook and eat is stingray.

Alice Law said...

*Clap Hands!!! Very informative indeed, you are so teler(smart)! Soak in vinegar for approx how long har? Smelling stingray while buying, what a great tip!

Thanks a lot for sharing, have a nice day ahead!

Christine said...

interesting information. I didn't even know they had bright red blood.

suituapui said...

Yup...I saw on AFC, somebody explaining all this but he also said sometimes, people add chemicals to keep the fish fresh and that causes the smell... So far, the ikan bakar I had in Penang, no smell...very nice - only those we get here.

Pete said...

Cleff : Ha ha ha, I know you like fishes that have very little bones....LOL!

Alice : Half and hour to one hour should be enough for the liquid to penetrate the flesh. Not too long or else the flesh would become soggy when cooked

Christine : They have very little blood.

STP : Normally they will not add any chemical to stingray because the cost is very much lower than other fishes and it is rather cheap when you buy them from the market. However you have to be careful with those expensive fishes like kurau, pomfret, kerapu.

Hayley said...

Wow, thanks for sharing! Very useful information...

yvonne said...

Thanks for the info :)

tuti said...

wah very informative. your blog got very nice makan to eat and at the same time can learn alot of things.

[SK] said...

wow, very informative post, thanks for sharing.. :)

Small Kucing said...

oo..like that. Noted. Thanks :D

mNhL said...

Now I know the answer. Had eaten a few times of smelly stringray.... Some friends even told me that a male stringray smell while a female one does not. hahaha.....

Anonymous said...

Bought stingray from tesco and asked my wife to cook asam pedas with it. Gravy was fine but the stingray flesh taste like piss. We both puzzled and now we know. Oh well lesson learned

Anonymous said...

Perfect explanation. Well said.

Anonymous said...

Learnt something new today.
I was puzzled at why the stingray i cooked in an oven toaster reeked of urea/urine smell that clogged my nose and went to google it, now i know why.
Thank you so much for the post!

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Unknown said...

Wash the meat repeated with common salt and at the end use two spoon of curd while washing the meat. Again add common salt to meat to wash the meat and drain it for atleast 15 minutes. While cooking cook in open lided. Don't close the the utensil while cooking. I made it on yesterday and it was delicious with no foul smell

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Anonymous said...

The vinegar tip worked perfectly! Thanks for saving my family stingray lunch!