Chloramphenicol policies, testing challenged
REGULATION aquaculture news from southeast asia
Shrimp Biotechnology ProgramNational Center for Genetic
Antibiotic residues in shrimp, and chloramphenicol in
particular, have been big issues in Asia recently, due
to the European Union’s implementation of both “zero tol-
erance” and enzyme-linked immuno-assay (ELISA) testing
for chloramphenicol residues. In early January, the E.U.
voted to ban imports of shrimp from China after the detec-tion of chloramphenicol in this and other animal products,
evidence, although measures can be adopted on a provi-
and concerns over the use of such banned substances in China.
sional basis and then revised when more information is
This move was quickly followed by action in the Unit-
ed States, which stepped up inspections of Chinese seafood.
Since then, the detection of chloramphenicol has led to im-
poundment and destruction of shipments from several Asian
Under the SPS agreement, countries are also free to es-
countries, including Vietnam and Thailand, which cost sea-
tablish their own levels of acceptable risk. They can adopt
a more stringent level than that which is recognized inter-nationally, as long as they can demonstrate the internation-
Concerns in Asia
al standard would not achieve their acceptable risk levels.
Fishery authorities in most Asian countries have ex-
pressed concerns about the E.U. action, with some suspect-
ing it is being used as a barrier to trade. In a keynote speech
Finally, the agreement requires that SPS measures be
at the ASEAN Fisheries Federation Meeting on Chloram-
based on an analysis and assessment of risks to life or
phenicol held in Jakarta, Indonesia in January, Dr. Rokhmin
health, and the probability of adverse effects on human or
Dahuri said the chloramphenicol issue was an example of
animal health from additives, contaminants, toxins, or dis-
how some developed countries systematically use nontariff
barriers as disguised restrictions to trade. Dahuri, Indone-sia’s minister of marine affairs and fisheries, questioned
whether the action was a measure intended to protect con-
To date, neither the Joint Expert Committee on Food
sumers’ health or pretext to impose a technical barrier to trade.
Additives and Contaminants nor the Codex Committee onFood Additives and Contaminants has established maxi-mum residue limits for chloramphenicol. In this situation,the E.U. is within its rights to establish its own level of ac-ceptable risk.
On the basis of the SPS agreement, however, it has been
questioned whether “zero tolerance” is a fair level of ac-ceptable risk. Zero tolerance has been likened to a require-ment for “zero risk,” which is not acceptable as a basis forimport prohibitions, since it effectively negates the needfor an import risk assessment. There is some degree of riskassociated with most, if not all imports.
In the past, the maximum residue limit was set in prac-
Alliance. Do not reproduce without permission.
tice by the limits of detection for the tests used. Changingfrom high-performance liquid chromatography (HPLC) to
Backed by lab results, shrimp exporters are questioning the
ELISA testing effectively reduced detection limits from 10
results of new test procedures used to detect chloramphenicol.
ELISA Testing Questioned
The World Trade Organization Agreement on the Appli-
Both the increased sensitivity and reliability of the
cation of Sanitary and Phytosanitary Measures (SPS) ac-
ELISA test have been questioned. Several instances have
cepts the rights of countries to adopt and enforce measures
been cited of different laboratories reporting different test
to safeguard human, animal, and plant health. However,
results, raising concerns about the reproducibility of the test.
such measures should not be applied in a manner to consti-
Several Asian exporters have gone to great expense to
tute a disguised restriction on international trade. They
buy equipment and set up the capability for routine chlo-
Copyright 2002, Global
should also not be maintained without sufficient scientific
ramphenicol testing by ELISA. In the past, this allowed ex-
porters to ensure that the product they bought met the stan-dards required by their customers.
However, experience in the present case has shown that
The major risk to human safety from chlorampheni-
negative tests in the processing plant do not necessarily
col exposure is through its role as a precursor to aplastic
mean subsequent testing in the importing country will also
anemia. Aplastic anemia occurs when bone marrow
prove negative. More than one exporter has questioned the
produces too few blood cells. The reduction in red blood
reliability of the method, given its high cost and uncertain
cells causes hemoglobin levels to fall, while reduced
numbers of white blood cells increase susceptibility toinfection. A fall in the number of platelets affects clot-
The increased sensitivity of ELISA tests has also raised
Aplastic anemia has several causes, some sporadic
doubts about their use in the context of zero tolerance and
and others that follow predisposing conditions. Among
trade. Tests conducted in Thailand by Prof. Piamsak Mena-
sveta of Chulalongkorn University and by other laborato-
Infectious diseases (e.g., infectious hepatitis)
ries on a range of food items purchased locally showed that
Medication (antibiotics and anticonvulsants)
ham, caviar, butter, and anchovies from Europe – as well as
Toxins (heavy metals)
similar items from other countries – have chloramphenicol
levels detected by ELISA at up to 1.38 ppb.
Positive tests for chloramphenicol in wild-caught squid
have also been reported, which may indicate a detectable
background contamination in nature or the possibility of
Chloramphenicol-related aplastic anemia is dose-
cross-reactivity of the test. It is clear a number of issues
related, varies from person to person, and is usually re-
concerning the application of ELISA tests must be resolved.
versible. The worldwide annual incidence of aplasticanemia has been estimated at 2-6 cases/million people.
Geographical differences in prevalence, with greater
Given the importance of the seafood industry to Asian
occurrence in Asia than the West, suggest that environ-
countries, the ASEAN Fisheries Federation has asked the
mental factors may also be involved.
European Union to consider the gradual application of itszero-tolerance requirement over a five-year period, and
The major risk to human safety
joint research by scientists from the E.U. and ASEAN coun-
from chloramphenicol exposure
tries to determine if the zero-tolerance approach is justified.
The detection of chloramphenicol residues in consumer
is through its role as a precursor
food products from the E.U. and other countries also sup-
to aplastic anemia.
ports the call for further study and a harmonized interna-tional standard to avoid unfair trade restrictions.
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