Food Safety 79
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persistent organic pollutants such as dioxins and
PCB, and by heavy metals such as lead, cadmium
and mercury.
The production of safe foods – by ensuring
plant and animal health, by applying HACCP
(Hazard Analysis and Critical Control Point)
principles and observing hygiene [4] – must,
however, be complemented by appropriate and
hygienic handling of food by consumers.
Residues
Residues in foods derive from deliberately ap-
plied substances, food additives, pesticides and
veterinary drugs. For these substances, maximal
residue levels (MRL) based on good practice (i.e.
application at levels to achieve the desired effect
but not higher) are defined. MRL must be com-
patible with acceptable daily intake (ADI) levels,
which are the amounts of a chemical that can be
ingested daily over a lifetime without producing
appreciable health risks. ADI levels do not apply
to infants below 3 months of age. Because infants
and young children have food patterns with less
variety than adults and they consume more food
per unit of body mass, lower MRL are required for
some pesticides in foods for infants and young
children [5] – or, for instance in the European
Community, the use of certain pesticides on crops
intended for infants and young children is forbid-
den [6]. On an international level, residue levels
are to be ‘reduced to the maximum extent possi-
ble’ for example in infant formulae, follow-on
formulae and cereal-based complementary foods
for infants and young children [7–9].
Contaminants
Contaminants from the environment in food are
unintended and often unavoidable – e.g. dioxins,
PCB and heavy metals – or are introduced during
processing. Naturally occurring contaminants
are fungal mycotoxins, particularly in cereals,
nuts and fruit juices. They are quite stable to nor-
mal cooking temperatures and toxic to the liver
and/or the kidney, and some are carcinogenic in
rodents. Maximum levels for different mycotox-
ins in various categories of food and animal feed
have been set in the majority of countries world-
wide [10, 11]. For all other mycotoxins which
cannot be completely eliminated in food and
feed, levels must be as low as reasonably achiev-
able.
Nitrate, which is accumulated by some plants
and can occur in water wells, is considered a con-
taminant, and maximum levels have been set for
ready-to-eat vegetable meals for infants. Nitrate,
by itself not very toxic, is partially converted into
nitrite, which can form carcinogenic nitrosa-
mines with secondary amines from food and
which can induce methemoglobinemia in young
infants at intakes of >7 mg nitrate/kg per day,
particularly in infants with still high levels of fe-
tal hemoglobin and/or concomitant gastrointes-
tinal or urinary tract infection. Home-prepared
meals containing vegetables potentially high in
nitrate (radish, beetroot, fennel, lettuce, kohlrabi
and spinach) should therefore not be stored and
rewarmed.
For other contaminants, both the Joint Expert
Committee on Food Additives and Contami-
nants (JECFA) and the European Food Safety
Authority (EFSA) have defined provisional toler-
able weekly intake (PTWI) levels ( table 1 ).
Heavy metals – particularly methylmercury
in seafood products, cadmium taken up from the
soil by plants, and lead mostly derived from in-
dustrial waste in plants and via feed in animal
food – are of particular concern for children be-
cause of their long half-life and because of neu-
robehavioral, neurotoxic and nephrotoxic ad-
verse effects, respectively.
Organohalogen compounds, e.g. dioxins and
PCB, accumulate and persist for many years in
body fat. They have adverse effects on develop-
ment, reproduction and the immune and endo-Koletzko B, et al. (eds): Pediatric Nutrition in Practice. World Rev Nutr Diet. Basel, Karger, 2015, vol 113, pp 78–82
DOI: 10.1159/000360319