00:00:08
Hello my name is Georges.
I am toxicologist at EFSA
00:00:12
and today I am here to talk to you about
00:00:13
the safety of chemicals in food.
00:00:15
First of all, why are
chemicals in food?
00:00:18
Well chemicals are
the building blocks of everything.
00:00:21
All foods and living matter,
including our bodies,
are made up of chemicals.
00:00:26
These include nutrients such as
carbohydrates, protein, fat
00:00:30
and many other elements
and compounds that all
contribute to our diet.
00:00:34
Most of the chemicals present in food
are harmless and often nutritious,
00:00:39
but some may be harmful if
our exposure to them is too high.
00:00:43
Before chemicals can be intentionally
used in food and animal feed,
00:00:48
scientists carry out
strict risk assessments
00:00:50
to determine which substances
can be used safely and at which levels.
00:00:56
This is also done for chemical
contaminants in the food chain.
00:01:00
So how much is safe?
00:01:02
Scientists who evaluate
the safety of chemicals
00:01:05
try to establish what we call
00:01:07
'health-based guidance values'
or 'safe levels'.
00:01:11
These define the maximum
amount of chemicals
00:01:14
that we can safely consume
each day or week,
00:01:17
during our entire lifetime.
00:01:19
The most common safe levels are ADI,
Acceptable Daily Intake
00:01:23
and TDI, Tolerable Daily Intake.
00:01:27
ADI is used for additives and
other substances purposely added to food;
00:01:35
and TDI is used for contaminants
like industrial pollutants
00:01:41
that may be unintentionally
present in food.
00:01:43
How do scientists define these safe levels?
00:01:47
Safe levels are based
on the scientific review
00:01:50
of all the toxicological data available
at the time on a specific chemical,
00:01:58
usually including
long-term tests on animals.
00:02:01
From this review,
a reference point is identified
00:02:05
for the most sensitive
adverse effect in animals
00:02:08
that is considered
relevant for humans too.
00:02:11
This reference value is usually a
‘no observed adverse effect level’,
00:02:16
the NOAEL, which is the greatest
concentration or amount of substance
00:02:23
which causes no detectable adverse effect
in the animals used in the tests.
00:02:28
The safe level is then
derived by applying
00:02:32
an uncertainty factor of
100: 10 to account
00:02:35
for the difference between
humans and animals,
00:02:39
and another 10 to account
for differences between humans,
00:02:44
such as those between
children and adults.
00:02:47
What happens if
we exceed the safe levels?
00:02:51
Exceeding the health-based
guidance values such as an ADI or TDI
00:02:55
on an occasional basis
is not necessarily a cause
00:02:58
for concern because
they are set
00:03:00
so as to take into account
exposure to a substance over a lifetime.
00:03:04
A good example is a dyke.
00:03:07
If the water occasionally
goes above the dyke,
00:03:11
it will not necessarily damage
the homes located behind it.
00:03:15
However, if the safe levels are exceeded
persistently over time,
показать еще
русский▼
English
