MILK LOAD TESTING FACES NEW HITCH

By DON STONEMAN

The Snap test kit and other inhibitor detection
field devices are great at picking up drug
residues. Sometimes a little too good. This is
costing the dairy industry money in downtime while
a laboratory test confirms that milk is safe for
consumers.
One drug, Ceftiofur, sold under the trade name
Excenel Sterile Powder, shows up at extremely low
levels in field tests. Dairy farmers don't need to
withhold milk from cows injected for respiratory
diseases with this drug. However, residues do
appear at levels as low as four parts per billion
(ppb) about half the time when the drug is infused
into cow's udders. 
This is an off-label use, explains Dairy Farmers of
Ontario's George MacNaughton, manager of farm
policies and programs. Farmers with this level of
residue showing up in their milk are not
necessarily at fault, since this treatment can be
prescribed by a veterinarian. 
Ceftiofur is equally likely to show up with any of
the test kits, MacNaughton says. Snap and the other
kits guarantee they can detect drug residues at 50
ppb 100 per cent of the time. But they will pick up
certain drug residues about half the time at much
lower levels. "All the test kits are the same. This
is not particular to the Snap," he says.
"We can't say its wrong" for that drug to be in
milk at extremely low levels, but if a vet didn't
write a prescription for producers, they aren't
supposed to use the drug, he warns.
The issue is costing the dairy industry money
because of downtime for milk board employees,
processors and truckers. Milk board staff have to
run the sample to the airport, and someone else has
to pick it up in Toronto and take it to Guelph to
get a result within 24 hours. In the meantime, the
truck full of milk has to sit at the plant until
results come back. This happens 15 to 20 times a
month, and 10 of these positives will come from
Ceftiofur-treated cows. 
This doesn't help milk quality either because the
truck is insulated, but not refrigerated.
It's a question as to whether costs should be borne
by the producer for these extra services,
MacNaughton says.
The issue was to go to the raw milk quality
committee at presstime, says its chairman, Drumbo
milk producer Grant MacLaren. He was not prepared
to speculate on what options might be available to
the board. Of paramount importance is food safety,
he said. That's why the load testing program is now
in place. Extremely sensitive tests are a
shortcoming of the new program. 
"The question is, what is the health issue? What is
happening at the farm to cause that?" MacLaren
says.
"We want to make sure we are meeting our
commitments to processors and consumers."
There are a number of field tests being used,
MacNaughton says. They all have the about the same
ranges of sensitivity. 

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