Food Packaging

Question-and-answer flashcards covering key concepts from the lecture on food packaging materials, functions, sustainability, barrier properties, migration, shelf-life, recycling and modern technologies such as MAP.

What are the TWO fundamental purposes of food packaging?

To CONTAIN the product and to PROTECT the product.

Why is packaging considered a "dilemma" in the food industry?

Because it extends shelf-life and reduces food waste, yet simultaneously creates large volumes of environmental waste.

What are the 3 R’s of sustainable packaging?

Reduce, Reuse, Recycle.

Which property of packaging is described by WVTR?

Water (moisture) Vapor Transmission Rate – the amount of water vapor that passes through a material per unit area per day.

Give the unit normally used for WVTR.

grams of water / m² / day.

In the WVTR equation (Q/AT = Pm ΔP / L), what does L represent?

The thickness of the packaging film or barrier.

Define ‘migration’ in the context of food packaging.

The movement of substances (e.g., gases, water, additives) across the packaging barrier, either into or out of the food.

What term is used when a packaging component moves INTO the food?

Leaching.

Name four key gases or compounds whose migration must be controlled in food packs.

Oxygen, water vapor, ethylene, volatile aromas/oils.

What is Bisphenol-A (BPA) and why is it controversial?

A plastic additive used in can linings and bottles; it can migrate into food and act as an endocrine disruptor, so it is restricted or banned in some markets.

Which plastic recycling code corresponds to PET?

Code 1 inside the Mobius loop symbol.

Why are aluminum beverage cans and coffee capsules marketed as ‘infinitely recyclable’?

Because aluminum can be melted and reused repeatedly with minimal loss of quality.

Which country pioneered mandatory recycling of all plastic packaging in 1990?

Germany.

Give TWO disadvantages of glass packaging.

It is heavy (high transport cost) and brittle/fragile.

What is the main advantage of glass for food?

Chemical inertness – it does not react with or taint the product.

What are ‘tamper-evident’ packages designed to do?

Show visible damage or change if someone has interfered with the product, increasing consumer safety.

State ONE famous food/health incident that accelerated tamper-evident packaging.

The Tylenol (cyanide) poisoning case in the USA.

Why do consumers often accept higher prices for convenience packs?

Because convenience (ease of use, portability, resealability) is valued more strongly than cost by many shoppers.

What process is used to fabricate hollow plastic bottles such as water bottles?

Blow moulding (extrusion-blow or injection-blow).

Name two common advantages of metal cans for food storage.

Excellent barrier to light/oxygen and very long shelf-life when correctly processed.

What is a ‘tin-plate’ can?

A steel can coated with a thin layer of tin to prevent corrosion and protect acidic foods.

Explain ‘modified atmosphere packaging’ (MAP).

Replacing the air in a food pack with a controlled gas mix (typically low O₂, elevated CO₂/N₂) to slow microbial growth and extend shelf-life.

Why are potato-chip bags filled with nitrogen?

Nitrogen flush provides a cushion to prevent breakage and displaces oxygen to avoid rancidity.

What is the primary packaging difference between brittle cookies and chocolate bars?

Cookies need rigid or sectioned packs to prevent breakage; chocolate mainly needs light- and moisture-barrier wraps.

Name ONE additive often included inside meat MAP trays to inhibit microbes.

CO₂-absorbing/antimicrobial pads under the meat.

Describe an accelerated shelf-life test.

Storing the product under elevated temperature or stress to speed up deterioration, then extrapolating to normal conditions.

Which single acid CANNOT be stored safely in glass?

Hydrofluoric acid (HF).

How did reducing glass beer-bottle weight from 260 g to 160 g help sustainability?

Lower raw-material use and lighter transport loads, reducing energy and emissions.

List FOUR desirable features of an ‘ideal’ package (even though no package is truly ideal).

Good barrier, affordable, strong/stackable, non-toxic (plus visually appealing, resealable, printable, etc.).

Why is recycling of mixed plastics difficult?

Different polymers have incompatible melting/processing temperatures and properties, and are not easily separated by simple sorting.

What does a ‘child-resistant closure’ aim to achieve?

Make it difficult for young children to open hazardous products (medicines, chemicals), while remaining accessible to adults.

Which packaging layer is called ‘secondary packaging’?

The grouping pack that surrounds multiple primary packs (e.g., corrugated carton holding 24 cans).

Give ONE reason fruits and vegetables may be packed in breathable perforated films.

To allow respiration gases (O₂/CO₂) to exchange and prevent condensation or anaerobic spoilage.

What Chinese invention (1st century AD) revolutionised printable food packaging?

Paper.