The occurrence of semicarbazide in the meat and shell of ... occurrence of semicarbazide in the meat...
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The occurrence of semicarbazide in the meat and shell of Bangladeshi fresh-water shrimp. Glenn Kennedy Head of Chemical Surveillance Branch AFBI-Stormont Belfast, Northern Ireland, UK [email protected]
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Transcript of The occurrence of semicarbazide in the meat and shell of ... occurrence of semicarbazide in the meat...
The occurrence of semicarbazide in the meat and shell of Bangladeshi fresh-water shrimp.
Glenn Kennedy
Head of Chemical Surveillance BranchAFBI-StormontBelfast, Northern Ireland, UK
Uses of nitrofuran drugs
• Disease treatment & prevention
• Growth promotion
• Used in pigs, poultry & aquaculture
• Banned in EU 1993-1995
• No methods to detect residues
• Very unstable
• FoodBRAND – Framework 5
FoodBRAND: new methods
Furazolidone AOZ
Furaltadone AMOZ
Nitrofurantoin AHD
Nitrofurazone SEM
Drug Bound residue
March 2002Nitrofurans in shrimp
My laboratory
A global problem !
China IndiaBangladeshThailandBrazilEcuadorTaiwanMalaysiaPortugalGreece
ItalyUAE PolandIndonesiaVenezuelaMadagascarBelgiumSri LankaArgentinaNorthern Ireland
MRPL – Reference Point For Action
Nitrofuran metabolites 1.0 µg/kg
Aquaculture in Bangladesh
Penaeus monodon (Bagda)Salt water cultivationTiger prawnExtensive production
Macrobrachium rosenbergii (Golda)Freshwater cultivationMore intensive cultivationFeeds: commercial & “market feed”Co-cultivation with rice110,000 farmsLong production chains
Penaeus spp (CN 0306 13 50) from Bangladesh
0
500
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3500Ja
n. 1
999
Jan.
200
0
Jan.
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0EU-2
7 Im
port
s (T
onne
s) Imports increasing with time
Peak exports: Jul-Sep
Other spp (CN 0306 13 80) from Bangladesh
0
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1000
1200
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1600
1800Ja
n. 1
999
Jan.
200
0
Jan.
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0EU-2
7 Im
port
s (T
onne
s) Imports in decline
Peak exports: Oct-Dec
Alerts: VMPs 2002 - 2009
0
50
100
150
200
250
300
350
400
45020
02
2003
2004
2005
2006
2007
2008
2009
Veterinary Medicinal Products 2009
Dyes
Nitrofurans
ChloramphenicolSulphonamidesTetracyclines
Others
Veterinary Medicinal Products 2009
Fish
HoneyShrimp
Milk
Meat
Poultry
Others
05
101520253035404550
1st 0
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2nd 03
1st 0
4
2nd 04
1st 0
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2nd 05
1st 0
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2nd 06
1st 0
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2nd 07
1st 0
8
2nd 08
1st 0
9
2nd 09
1st 1
0
2nd 10
Bangladesh: Nitrofuran RASFFs
To RASFF Week 43
Bangladesh rejections 2008 & 2009
Almost all from Belgium
Some from United Kingdom
All recent positives – one nitrofuran
Semicarbazide
H2N NH
NH2
O
SEM
March 2008: started to test shell-on tails
Tissue-bound SEM residues detected
Question: A good idea or bad idea?
Either: naturally occurring in shellsa bad idea
Or: Nitrofurazone (metabolite) binds to chitina good idea
Nitrofurans & Belgium
Nitrofurazone and semicarbazide
The purpose of this short paper is to review the current status of semicarbazide (SEM)
as a putative metabolite of nitrofurazone and to comment on the possibilities that
SEM may have a source unrelated to the deliberate or inadvertent administration of
nitrofurazone.
1) Is SEM a metabolite of nitrofurazone? Four independent lines of evidence support the contention that SEM is a metabolite of
nitrofurazone, in exactly the same way that AOZ is a metabolite of furazolidone.
May 2003
5) Choice of method/sample
Based on current information, the only likely source of possible false positive results
involving SEM originates from the alleged occasional presence of SEM in materials
used in product coatings. This may cause concern if total residues are determined in
the whole product, as opposed to tissue-bound residues in the meat part of the
product. We are therefore firmly of the opinion that the most appropriate method to
use is detection of bound residues (as opposed to total residues) in poultry/prawn meat
(rather than in the finished product). In our view, this will minimise the risks of false
positive results and will remove any criticism that the methods are being applied to
sample matrices for which they have not been appropriately validated.
May 2003
December 2003
Field work – BSFF, Dhaka
Analytical work – AFBI Belfast
Wild-caught shrimp – different locations
Snail meat
Feedingstuffs
Shrimps previously tested at FIQC
Field study - Bangladesh
Location & DateNitrofuran
parents (µg/kg)
SEM (µg/kg)
Bagherhat 12/08/09 <CCα N.D.Khulna 12/08/09 <CCα 34.3Khulna 12/08/09 <CCα N.D.Khulna 12/08/09 <CCα N.D.Khulna 12/08/09 <CCα N.D.Khulna 12/08/09 <CCα 7.3Khulna 12/08/09 <CCα N.D.Bagherhat 12/08/09 <CCα N.D.Khulna 12/08/09 <CCα N.D.Khulna 12/08/09 <CCα N.D.
Brahmonbaria 30/07/09 UpstreamBrahmonbaria 30/07/09 UpstreamBrahmonbaria 30/07/09 UpstreamHobigong 28/07/09 UpstreamHobigong 28/07/09 UpstreamHobigong 28/07/09 UpstreamKishorgong 29/07/09 UpstreamKishorgong 29/07/09 UpstreamKishorgong 29/07/09 UpstreamKishorgong 29/07/09 UpstreamKishorgong 30/07/09 UpstreamKishorgong 30/07/09 UpstreamKishorgong 30/07/09 UpstreamKishorgong 28/07/09 UpstreamKishorgong 28/07/09 UpstreamKishorgong 28/07/09 UpstreamMunshigong 03/08/09 UpstreamChandpur 04/08/09 MidstreamChandpur 04/08/09 MidstreamChandpur 0/08/09 MidstreamChandpur 04/08/09 MidstreamKishorgong 30/07/09 MidstreamKishorgong 30/07/09 MidstreamBagherhat 11/08/09 DownstreamBagherhat 11/08/09 DownstreamBagherhat 12/08/09 DownstreamBagherhat 12/08/09 DownstreamBagherhat 12/08/09 DownstreamBagherhat 11/08/09 Downstream
Wild catch shrimp
Upstream
Around
Downstream
Sampling
Effect of sampling point
Upstrea
m
Midstrea
m
Downstrea
m0.0
0.2
0.4
0.6
0.8
Sampling point
Tiss
ue-b
ound
SEM
(µg/
kg)
No significant differencesSome “fliers”SEM occurs naturally?
SEM in shells
Upstrea
m
Midstrea
m
Downstrea
m0
100
200
300
Sampling point
Tiss
ue-b
ound
SEM
(µg/
kg)
No significant differencesSEM occurs naturally.
Comparison – meat & shellEffect of sampling point
Upstrea
m
Midstrea
m
Downstrea
m0.0
0.2
0.4
0.6
0.8
Sampling point
Tiss
ue-b
ound
SEM
(µg/
kg)
SEM in shell ~ 100 times higher than meat
SEM in shells
Upstrea
m
Midstrea
m
Downstrea
m0
100
200
300
Sampling point
Tiss
ue-b
ound
SEM
(µg/
kg)
SEM occurs naturally in Golda shell
Testing of tail & shell together: inadvisable
Field study - Conclusions
Can high levels in shell “contaminate” meat?
SEM in "cored" samples
Inner meat Outer meat0.0
0.2
0.4
0.6
0.8
1.0
Sample (n=12)
SEM
(µg/
kg) P < 0.02
Inner meat Outer meat Soft shell0
5
10
15
SEM
(µg/
kg)
New cuticle synthesised in epidermal layer
Old shell shed to allow for growth
SEM appears to be surface associated
What happens to the epidermis ?
Associated with shell or meat ?
Shrimp epidermis
Meat
Epidermal layer
Shell
Chemical composition of chitin
Unusual amino acids from algae
“Secondary metabolites” from other organisms
What could be happening?
H2NNH
O
NH2
Gigartinine
Similar to SEM
Does release SEM
When analysed for nitrofurans
O
OH
NH2
NH
O
NH
H2N
NH
Secondary metabolites
NH
N
O
NH2
HN
H2NNH
O
NH2
Trying to source this compound
Findings in other widely farmed species
Tissue-bound SEM in shells of:
Penaeus monodonBlack Tiger prawn18.2 ± 5.3 µg/kg (n=5)
Litopenaeus vannameiPacific white prawn6.2 ± 2.8 µg/kg (n=5)
Next step?
SEM occurs naturally in shrimp shells.
Epidermal SEM can contaminate meat
Is the presence of SEM a risk to health?
Is the use of nitrofurazone a risk to health?
Is there an alternative?
Analyse sample “core” for “bound” residues?
Is the MRPL/RPA reasonable?
