Trace levels of the antibiotic chloramphenicol have been
found in a number of batches of
honey, especially from Asia. Although the levels being found are very low, due
to it's toxicity it is
considered an illegal
contaminant at any level. Most countries are now testing down to
a level of 0.3 ppb. Several
analytical methodologies have emerged to enable reaching these low levels. At
Columbia Food Laboratories we have set up analytical methods using two of these
techniques:
ELISA (enzyme-linked immunosorbent assay)
This is a quantitative screening method with a lower detection limit of
0.3 ppb. It is widely used in Europe and
appears to be highly regarded. Due to the nature of this type of assay, false
positives are a slight possibility. False negatives are less likely. We have
found a few instances where this method has given a false positive result in
honey at or below the 1 ppb level, although recent improvements in the ELISA
kits seem to have reduced this possibility. To keep the cost of this test to a minimum, we are not attempting to quantitate
levels above 10 ppb, but will report such results as ">10 ppb" (greater
than 10 ppb).
P176 Chloramphenicol (by ELISA) Price: $85/sample
HPLC/MS (high pressure liquid chromatography/mass spectroscopy)
This is a highly specific quantitative method with a minimum
quantitation limit of 0.3 ppb. We use high resolution time-of-flight MS,
therefore, the identification of CAP can be made with much greater certainty.
Often our customers use this method as a test upgrade to confirm samples which
test positive by ELISA. Due to
the additional time required for sample preparation and the high cost of the
instrumentation involved, this method is more expensive to perform.
P177 Chloramphenicol (by HPLC/MS) Price:
$180/sample
