Welcome to the Grower Pesticide Safety
Course and Chapter 22 Pesticides and
Food. Chapter 22 starts on page 247 of
the manual. There are nine slides in this
presentation and it will take you about
ten minutes to review. By the end of this
lesson you should be ready to, define
pesticide residue and Maximum Residue
Limit, identify the organizations who
tests for residues, list ways to prevent
pesticide residues, calculate spray dates
based on pre-harvest intervals. Food
safety is important for consumers. Food
product recalls and safety alerts are on
the rise and they concern the public.  Consumers want to know what substances
that may be on their food. For example,
residues from pesticides or substances
that cause allergic reaction. Some
consumers also want to know about
pesticide residues on other products
that they handle, such as bedding or
indoor plants, cut flowers and sod. the
fact is over 90 percent of all food
samples had no detectable residue or
residue below the Canadian maximum
residue limits and we'll discuss that a
little bit further on, some of the
details in that statement.  First, a
pesticide residue is the amount of
chemical or biological pesticide that
remains on a crop, animal or surface
after it has been treated. Scientists
are able to detect very small amounts of
pesticide residues now,
What is the Maximum Residue Limit, and
the short form is MRL.  MRL is the
greatest amount of pesticide residue
that can be in or on food when the
pesticide is used according to the label
directions. These residues are not
harmful. Canada's MRLs are set by the
Pest Management Regulatory Agency Health
Canada. They're published online on the
Health Canada Maximum Residue Limit
database which we'll look at in a moment
and set for each pesticide on each food
crop in parts per million, ppm. Here's a
look at the screen of Health Canada's
Maximum Residue Limit database.  Health Canada
sets science-based
Maximum Residue Limits to ensure the
food Canadians eat is safe. The MRLs set
for each pesticide crop combination are
set at levels well below the amount that
could pose a health concern. So you can
go on to the database and search. You can
put in a particular active ingredient, a
chemical common name, Spinosa here is one
I did a search on then,and then  I picked my food
commodity which was strawberries and I
received the statement that the MRL
value is 0.7 so MRLs would be in parts
per million so 0.7 parts per million. And
there's a date there that indicates that
it was established on July 9th of 2008.
Let's think about how small that value
is. What is a part per million?  Parts per
million, ppm, is used to describe very
small contaminants in the environment. So
that's one part pesticide for 1 million
parts of the food. An example
one penny in every ten thousand dollars
would be a part per million. One minute
in two years is a part per million. So
it's a very very small amount. Let's talk
about who tests for residues. So PMRA, 
the CFIA, the Canadian Food
Inspection Agency, and OMAFRA, the Ontario
Ministry of Agriculture, Food and Rural
Affairs and food processors all test
for residues. First PMRA checks to
make sure that pesticide users are
following the requirements of the Pest
Control Products Act and the label
directions.  So possible violations under
this Act would include the use of
unregistered product or off-label use of
a registered product. If the PMRA finds
illegal residues in a farmer's
crop it has a number of options to
follow through on. The farmer may have to
pay a fine or the farmer may have to
complete a training program but there
will be some follow up by the Pest
Management Regulatory Agency. The
Canadian Food Inspection Agency has the 
authority to inspect food producing
facilities and to sample and test food
products to make sure that requirements
of the Food and Drugs Act are met. So
they sample food produced in Canada or
imported into Canada from another
country. And they also do things like
animal feed not consumed by humans but
consumed by animals. The Ontario
Ministry of Agriculture, Food and Rural
Affairs while CFIA monitors for
imports of food into Canada OMAFRA plays 
a major role in monitoring the food that
is produced in Ontario. Numbers of samples
are collected of each commodity and
depends on the history of residue
problems,
the amount of food produced and how much
and how often people eat the food. So
their sampling program is looking for
residues of registered pesticides
greater than the Maximum Residue Limits,
residues of unregistered pesticides -- so
we have a pesticide on a crop that is
not supposed to be there and residues of
off-label uses of pesticides.  Off-label
use is the most common type of residue
problem found and it's illegal to use a
product for any purpose that is not
listed on that product label so keep
that in mind if you have a pesticide
that's able to be applied to broccoli
unless another crop such as cabbage is
on that label you cannot use it on the
cabbage. So how can you prevent residues?
Following all label directions, Applying
to the crops, animals, pests stated on the
label directions at the stated growth
stage. Use the pesticide rate stated on
the label and calibrate your equipment
to apply that rate accurately. So you'll
see some label statements  -- Do not use
more than three applications per season.
The reason that's there is to keep
pesticide residues within, below the
Maximum Residue Limit. Do not apply
within seven days of harvest of
blueberries or whichever crop it is. There could be days to harvest for a
number of crops. Take a look at that
mark down when you make your application
and mark down when you can go back in to
start the harvest. You want to make sure
that the residues are within the Maximum
Residue Limit at the time of harvest. And
you may have a label statement that says
"Allow a seven-day interval between
treatments". Again, the label statement has
it there for a number of reasons one of
those could be that the residues must not accumulate and
have time to degrade over time. So
our last slide here is just a little
practice question and this is also in
your manual. And we just want to make
sure that you can figure out what the
earliest date and time that a crop could
be harvested and here's an example -- 
Proper timing of application is critical
with this product. Monitor for insect
pests and treat at early larval stages.
Apply no more than four applications per
year. Rotate the application with other
insecticides. the pre-harvest interval is
three days. Apply at intervals of at least
seven days. Do not feed crop refuse to
livestock. Apply 0.5 liters per hectare
in at least 400 liters of water to
control the insect. Do not re-enter
treated areas within 12 hours.
All right. So you make your first
application of this pesticide to the
food crop on August 2nd at 7:00 a.m. and
you finish at 10:00 a.m. You plan to
make 3 applications and these will be 7
days apart.
It does say apply at intervals of at
least 7 days. What is the earliest date
and time that this crop can be harvested
for food use?  All right, so our first
application is August the second. We started
at 7 in the morning and finished at
10:00 a.m. It took us three hours. We're
going to make three applications in
total so we need to make another
application seven days apart --  that'll be
on August the 9th. Ideally we should do
that starting at 10 o'clock and
finishing at 1 o'clock and then we
follow through with a third application.
We start at 1 o'clock and we finish at 4
o'clock.
So what is the earliest dated time this
crop could be harvested for food use?
Well we know that it said up in our
question, the pre-harvest interval is 3
days. So we count three days from 16. We
would end up with it being on the 19th
of August, and since our last time of
application would be 4 p.m., we should
not harvest until after 4 p.m. on August
the 19th.  That's an overview of
pesticides and food, concentrating mostly
on Maximum Residue Limits and making
sure we don't have any pesticide
residues in our food when we're using
pesticides.
