Thursday,29 March,2012 08:09:50
In the latter part of last year and the early part of this year Japanese and Canadian government screening has unearthed many examples of higher than allowed enrofloxacin residues in farmed catfish (basa and tra or pangasius) and shrimp. It is not clear if there are only a few companies that are doing this or if it is widespread. From my perspective, either would not be surprising. It is important though to appreciate that it is highly unlikely that even if a consumer were to consume fish or shrimp that had just been fed this antibiotic that it would pose any measurable threat to the consumer. The threshold levels that have been legislated for antibiotics are determined by technology limitations and not by risk assessment.
This makes for ready fodder for NGOs that want to scare the public into believing that they are consuming something that could harm them or for competitive industries that believe that trying to undermine public confidence in an imported product is a constructive way to deal with competition.
Buying and using antibiotics in the U.S. for use in aquaculture can carry stiff penalties if unapproved antibiotics are used. This discourages their use, although realistically a farmer that is faced with a catastrophic loss of his crop could resort to doing whatever it takes to mitigate this. Generally farmers are well educated, understand the risks and focus on using those few antibiotics that are approved by the FDA. They understand withdrawal times and may have insurance in the event of a catastrophic loss.
In Vietnam the case is different. Farmers are not usually well educated and they are easily taken advantage of by salesmen that care more about their immediate profits then helping the customers to better understand what they are doing wrong and to correct it.
Despite the myths pangasius are just as susceptible to disease as other fish species and they are typically cultured at extremely high densities since they can breath air if dissolved oxygen levels are too low in the water. This is a stress and culturing fish at these extremely high densities allows for ready transmission of pathogens between fish.
Diagnosis of the underlying cause of mortality is rarely done and farmers have to resort to whatever tools that have available to stave off financial disaster. The same goes for shrimp. As rearing densities increase and farmers take short cuts they see more disease. Enrofloxacin is readily available. It is important to understand as well that in the U.S., there are only a few antibiotics that are available for treating specific bacterial diseases. Use of any other antibiotics (there are some exceptions) is problematic and there are many who believe that the U.S. should be telling countries that the only antibiotics that can be used on fish or shrimp imported into the U.S. are those that are approved for use in the U.S. This would cause serious hardship for a large number of farmers and encourage cheating.
What can Vietnam do? The government can step in and require that all product that is exported be screened by government labs or trusted third-party labs. Alternatively harvest permits can be issued to farms only after testing reveals that there are no residues. Banning the use of enrofloxacin will only drive its use underground (if it has not already been done so). By properly following withdrawal and usage guidelines much of the trouble can be avoided. Educating farmers can be helpful although without some form of penalty that is actually enforceable for not following the guidelines there is little hope of the situation being remedied.
Typically when violations of this type are as common as are being reported, there can be very serious repercussions with complete import bans being enacted on the species of concern. This would be economically injurious and disastrous to Vietnam as well as many suppliers if a major importer, such as the U.S. or EU were to do this. What is curious in all of this is why the U.S. is apparently not reporting the same thing. There are some that argue that this might be a reflection of the U.S.’s inadequate screening testing.
The bottom line is that the ultimate responsibility for this lies with the importer. They should be ensuring that their suppliers comply with the legal requirements. This is readily achievable by having routine unannounced audits of processing plants and requiring that all product be tested using ELISA to start on each lot and more sophisticated technologies for corroboration. Relying entirely on third party for profit certifications, while useful, does not relieve the importer of this responsibility. If bans or mandated government screening forcing many month delays while product is being tested are enacted then there will be dire economic consequences.