20
1 Chemicals in the Food and Beverage Industry: An Introduction
is known about the acute toxicity of a chemical than about its chronic toxicity.
Our understanding of acute toxicity usually comes from studies with animals that
have been exposed to relatively high doses. Accidental overexposure, spills, and
emergencies have allowed us to learn more about acute toxicity in humans. Health
effects can be temporary, such as skin irritation, illness, or nausea, or permanent:
blindness, scarring from acid burns, reduced intellectual capacity, etc. (Hellman
2003; Silbergeld 1998; Stellman 1998).
Acute toxicity often is observed within minutes or hours after sudden and intense
exposure to a chemical. However, effects of exposure to high concentrations may
appear later. For example, symptoms associated with intense exposure to certain
pesticides may not appear for several days.
1.8.1.2 Chronic Toxicity
Chronic or long-term toxicity has been studied so far in animals. In addition, we
have also learned a lot from studies of groups of people exposed in the workplace to
chemicals for years (Hellman 2003; Silbergeld 1998; Stellman 1998). Several studies
also concern food operators (Damalas and Koutroubas 2016).
As a general rule, chronic toxicity appears many years after the initial exposure.
The disease develops only because there has been repeated exposure over many years.
Diseases of chronic toxicity do not appear to be caused by single, sudden exposure.
Chronic toxicity is believed to involve either of the following two mechanisms, which
can be illustrated using sodium fluoride and n-hexane as examples:
(1) Sodium fluoride, in very low concentrations (as in toothpaste or drinking water),
does not cause visible harmful effects, even after years of exposure. Even at these
low concentrations, effects are positive for teeth. However, when the body is
repeatedly exposed to much higher concentrations, sodium fluoride is deposited
and accumulated in the bones. At first, the amount of fluoride is not a problem,
but after years of repeated exposure to high doses, there may be symptoms of
bone disease
(2) n-hexane does not deposit and does not accumulate in the body. It degrades
in the liver. A breakdown product can ‘attack’ nerve cells in the fingers and
toes. These cells do not regenerate easily. Over the years, continuous exposure
increases cell damage to such an extent that symptoms occur in the nerves of
the fingers and toes.
A special case of chronic toxicity is cancer. Repeated exposure to certain chemicals
for long time periods can cause cancer. Although there is no compelling evidence
that cancer can develop after a single exposure, most cases suggest that repeated
exposure over a long period is necessary (Kasbi-Benassouli et al. 2005).
Moreover, there is a tendency to believe that if small amounts of a chemical are
enough to cause intoxication, the chemical is in principle very dangerous. This is not
necessarily the case.
1 Chemicals in the Food and Beverage Industry: An Introduction
is known about the acute toxicity of a chemical than about its chronic toxicity.
Our understanding of acute toxicity usually comes from studies with animals that
have been exposed to relatively high doses. Accidental overexposure, spills, and
emergencies have allowed us to learn more about acute toxicity in humans. Health
effects can be temporary, such as skin irritation, illness, or nausea, or permanent:
blindness, scarring from acid burns, reduced intellectual capacity, etc. (Hellman
2003; Silbergeld 1998; Stellman 1998).
Acute toxicity often is observed within minutes or hours after sudden and intense
exposure to a chemical. However, effects of exposure to high concentrations may
appear later. For example, symptoms associated with intense exposure to certain
pesticides may not appear for several days.
1.8.1.2 Chronic Toxicity
Chronic or long-term toxicity has been studied so far in animals. In addition, we
have also learned a lot from studies of groups of people exposed in the workplace to
chemicals for years (Hellman 2003; Silbergeld 1998; Stellman 1998). Several studies
also concern food operators (Damalas and Koutroubas 2016).
As a general rule, chronic toxicity appears many years after the initial exposure.
The disease develops only because there has been repeated exposure over many years.
Diseases of chronic toxicity do not appear to be caused by single, sudden exposure.
Chronic toxicity is believed to involve either of the following two mechanisms, which
can be illustrated using sodium fluoride and n-hexane as examples:
(1) Sodium fluoride, in very low concentrations (as in toothpaste or drinking water),
does not cause visible harmful effects, even after years of exposure. Even at these
low concentrations, effects are positive for teeth. However, when the body is
repeatedly exposed to much higher concentrations, sodium fluoride is deposited
and accumulated in the bones. At first, the amount of fluoride is not a problem,
but after years of repeated exposure to high doses, there may be symptoms of
bone disease
(2) n-hexane does not deposit and does not accumulate in the body. It degrades
in the liver. A breakdown product can ‘attack’ nerve cells in the fingers and
toes. These cells do not regenerate easily. Over the years, continuous exposure
increases cell damage to such an extent that symptoms occur in the nerves of
the fingers and toes.
A special case of chronic toxicity is cancer. Repeated exposure to certain chemicals
for long time periods can cause cancer. Although there is no compelling evidence
that cancer can develop after a single exposure, most cases suggest that repeated
exposure over a long period is necessary (Kasbi-Benassouli et al. 2005).
Moreover, there is a tendency to believe that if small amounts of a chemical are
enough to cause intoxication, the chemical is in principle very dangerous. This is not
necessarily the case.