Pediatric Nutrition in Practice

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crine systems. Both for heavy metals and organo-
halogen compounds, maximum levels in food are
recommended by the Codex Alimentarius and
stipulated in national food law.

F o o d T o x i c o l o g y

The risk assessment of compounds used deliber-
ately in the production of foods differs from that
of contaminants, but the procedure is similar. For
deliberately added compounds, ADI levels are set
based on identified ‘no observed adverse effect
levels’ (NOAEL) from the most sensitive study in
the most sensitive species, and by dividing the
NOAEL by a safety factor (most often of 100) to
account for interspecies and intraspecies variabil-
ity in sensitivity. Safety factors can be modified
according to the quantity and quality of available
data and by taking into account the severity or ir-
reversibility of an effect. The result of the same
procedure applied to contaminants is a tolerable

daily intake, or in the case of contaminants with

long half-lives, a TWI (or PTWI if awaiting more

data to become available). Dividing the NOAEL

by the actual exposure of consumers permits an

estimation of the margin of safety.

Compounds with genotoxic and/or carcino-

genic activity presumably have no threshold for

effects. Instead the margin of exposure can be es-

timated, that is, the ratio between a defined point

on the dose-response curve in an animal carcino-

genicity study and the human intake. A margin

of exposure of 10,000 or higher is considered to

be of low health concern [1 2].

Short-term intakes of a residue/contaminant

in excess of ADI/tolerable daily intake levels do

not necessarily entail adverse health effects.

However, children may be particularly suscepti-

ble, and their expected lifespan and, therefore,

the available time for the manifestation of ad-

verse effects are longer. Table 1 lists toxicological

data on some important contaminants.

Ta b l e 1. Toxicological data on some relevant contaminants in food

Substance Most recent
assessment

Species Relevant

endpoint

LOAEL per kg

body weight

per day

(P)TWI per kg

body weight

per week

Methylmercury JECFA, 2003
NRC, 2000
EFSA, 2012

Prenatal

exposure of

children

Neurobehavioral

development

PTWI 1.6 μg

PTWI 0.7 μg

TWI 1.3 μg

Lead JECFA, 2000;
retracted in 2010 by
EFSA and JECFA

Human Neurotoxicity PTWI 25 μg

No threshold

Cadmium JECFA, 2010
EFSA, 2011

Human Renal toxicity PTWI 5.8 μg

TWI 2.5 μg

Dioxins and
dioxin-like PCB

SCF, 2001 Rat Development,

reproduction

TWI 14 pg

WHO-TEQ

Ochratoxin A JECFA, 2001
EFSA, 2006, 2010

Pig Renal toxicity 8 μg

8 μg

TWI 100 ng

TWI 120 ng

LOAEL = Lowest observed adverse effect level; NRC = National Research Council (USA); SCF = Scientific Committee
on Food of the European Commission; TEQ = toxicity equivalent.

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