PLASTICS AND HEALTH IMPACTS - Plastics and Environmental Sustainability - page 355

where c is the concentration of the migrating chemical in the packaged
(food)content, t isthetimeand x isthedistanceacrossthepackagewall,and
D P is the diffusion coefficient. Since the packages remain on the shelf or in
storage for long durations, it is the equilibrium concentration ofthe migrant
chemical in the contents, rather than its rate of diffusion that is of interest.
The partition coefficient K sp quantifies this concentration and is defined as
theratiooftheequilibriumconcentrationofmigrantinthefoodorsimulant,
C s , to that in the plastic packaging material, C P (the subscripts s and p refer
to simulant and plastic, respectively):
The value of K s/p varies with the temperature, the chemical species, as well
as the type of plastic used in the package. The package also has a second key
interface: that between air/plastic with a value K a/p .
In lab assessments of migration of additives, food simulants such as dilute
(3%v/v)aceticacid,10%and20%(v/v)ethanol, oliveoilanddistilled water
are commonly used in place of actual food items. Foods that are high in
lipidsmaypartitionhydrophobicadditivemigrantsatconcentrationshigher
than indicated in standard tests (Sanches Silva et al., 2007). The levels of
such migrating compounds will be low, especially in aqueous extracts, and
analytical protocols need to be followed closely to quantify them (Nerin et
al., 2013). In typical laboratory testing, the food simulant is allowed to be
in contact with the packaging for fixed durations at a constant temperature,
and the migrant concentration in food and/or package is analyzed. Bhunia
et al. (2013) has compiled a detailed list of migration studies for common
plastic packaging systems.
Typical migration data for eight additives, mostly plasticizers in several
different commercial packages, illustrates typical data (Fasano et al., 2012)
and are summarized in Table 8.5 . As phthalates are EDCs, their migration
into packaged food is a particular concern. The following were studied:
di-(2-ethylhexyl)phthalate (DEHP), diethylphthalate (DEP),
di- n -butylphthalate (DBP), butylbenzylphthalate (BBzP),
di- iso -nonylphthalate (DiNP), di- n -octylphthalate (DnOP),
diisododecylphthalate (DiDP), nonylphenol (NP), and bis phenol A (BPA).