food contact materials & toxicants Flashcards by Nancy He

The major food contact materials: (6)

metal (aluminum, stainless steel, Cu, Fe, titanium, etc)
glass
ceramic
wood
paper/carboard
plastic/polymers

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What are plastic polymers made of?

monomers + other “building block” substances (need many units)
ADDITIVES: organic or inorganic

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What are the plastic polymer types? (6)

polystyrene (PS)
polyethylene (PE)
polypropylene (PP)
polyvinyl chloride (PVC)
polyethylene terephthalate (PET)
polycarbonate (PC)

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What are the purposes of additives in plastic?

plasticizer (softer, flexible)
flame retardant
stabilizer (last longer)
lubricating (feel smooth)
pigment

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Why might some materials be of concern for food processing/packaging?

chemicals may migrate into food

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what chemicals may migrate from a metal can? (2)

metals from corrosion

- epoxy resins from inner polymer coating

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What can migrate from enamel materials?

metals, from pigment and material

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plastic wraps and materials can lead to migrating ____, ____, and also _____ due to ______.

monomers, additives, breakdown products; thermal/photodegradation

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How might PCPs be introduced to food from packaging?

From treated wood

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What is a good information source for food safety recalls?

RASFF portal (from european commission)

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what is ITX, and how was it implicated recently in food safety?

isopropyl thioxanthone
(used as photoinitiator in ink, on packaging label)
found in baby cereal + formula
very good at migrating, can even penetrate through plastic!

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what 2 well known plastic additives are routinely measured for food safety?

BPA (bisphenol A)

phthalates (DEHP)

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What is the role of phthlates in plastic?

plasticizer; soften and make flexible/pliable

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phthalates are (hydrophobic/hydrophilic) and can be easily extracted by _____ foods.

hydrophobic

oily

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The plasticizer DHP is a type of _____, and given IARC classification of ___. What are the toxicity effects?

pthalate
2B
possible carcinogen, testicular toxicity, fertility/developmental toxicity (possible endocrine disruptor)

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An example of a degradation product from plastic is ______, which may cause damage on _______.

semicarbazide

bone, cartilage, aorta

What are potential toxicity effects of BPA?

cause changes in liver/kidney

reproductive toxicity

is BPA in food plastics of significant concern? Why or why not?

No; exposure levels are much lower than the high amounts needed for reproductive toxicity effects

Why might elimination of BPA or other additives be problematic

need to replace with other additive to maintain plastic quality!
new additives may be untested, even more unsafe

What is an endocrine disruptor? give some examples

compounds that interfere with hormone system in human body

can block hormones, mimic hormones -> affect hormone action or behaviour (very complex)
ex: POPs (PCBs, PBDEs, DDT), phthalates, phenols (BPA, etc)

true/false: bottled water is a particularly concerning source of phthalates

False; lower levels in water than food, and unlikely to come from packaging material itself

The migration of chemicals between packaging and food is a _____ process, and assumed to follow _____.

diffusion

Fick’s Law of diffusion

What causes the diffusion of chemicals into food?

Higher concentration in packaging -> migrate to area of lower concentration

A substance that diffuses (fast/slow) will quickly reach _____. The relative concentrations in the material vs food is the _____.

fast; equilibrium (no more change in conc)

partition coefficient

the level of migration depends on:

1. time 2. product composition (affinity for compound) 3. pH 4. temp (hotter -> faster diffusion)

Migration tests are usually conducted at ____ C. Why?

40C | mimic accelerated migration (worst case scenarios)

What types of assays can be used for migration tests?

1. use real food items 2. use food simulants 3. computer models

pros/cons of using real food items for migration tests:

pros: more accurate for that specific food, mimic real life scenario cons: need to reassess for different foods, intensive process to extract analyte to determine migration

What is the process for a real food item migration test?

in contact with material for 3-5 days | extract, purify, analyze for compound

What are food simulants, and what is the advantage of using them instead of real food?

substances (made from pure chemicals) that mimic behaviour of food matrix under worst case scenario conditions - "cleaner" matrix (less interference), easier extraction, applicable for many foods of that type

How does a computer model work for migration tests?

Input certain parameters (food and polymer composition, time, temp, etc) use mathematical model

As time continues, the rate of migration will (increase/decrease), while the content in the food will (increase/decrease).

decrease (migrate more slowly) | increase

HOw are food simulant migration tests conducted?

in contact with material for specified time (and temp) | extract and quantify with ICP-MS (metal) or GCMS, LCMS/MS (organics)

The main simulant types: (5)

``` ACETIC ACID 3% (acidic foods) ETHANOL 10% (aqueous food) ETHANOL 50% (Liquor, dairy) VEG OIL (fatty food; bulk or surface) TENAX (dry food) ```

What is "tenax?"

sorbent powder used as food simulant (determine if substance can migrate thru air layer into powder)

In simulant testing, it is conducted at much (higher/lower) temperatures than the anticipated storage/usage temp. Why?

higher | need to mimic worst case scenario (subject to high heat, microwaves, etc) to anticipate possible situations in usage

What are the different regulations for food contact materials

Canada: based on VOLUNTARY pre-market assessment US: approved list of polymers that can be used EU: list of monomers and additives permitted, along with SML regulations (max permitted residue in food, or quantity in material)