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The packaging debate

The debate on packaging is mainly about how to market milk, cheese and yoghurts. The Vista Alegre farm dairy initially chose to sell yoghurts in glass pots, pasteurised milk and fresh cheese in PET or LDPE plastic containers and our soft, fine and mature cheeses in paper. In November 2018 we changed the pasteurised milk packaging to plastic and glass bottles and in 2021 we changed the PETplastic containers of our fresh cheeses for bioplastic (PLA). Additionally, we have chosen pots and bottles of given sizes. Why?

1. Glass or plastic pots and bottles?

2. PET and LDPE plastics and PLA bioplastics

3. Conclusions

4. Keys points for evaluating recycling

5. What container size or capacity?

6. Size and type of containers used in the Vista Alegre farm dairy

Glass, plastic or bioplastic pots and bottles?

Using some sort of packaging is inevitable for marketing milk and yoghurt. Several points should  be considered when deciding exactly which material and what size containers to use:

•    The implications of a given material for human health and standards of hygiene standards: material used to manufacture a container for food or beverages should be inert and thus not transfer any substance to either to the product it holds nor to the environment and it should weigh as little as possible bearing in mind it will at some point have to be lifted and carried by consumers.

•    The environmental cost of the manufacture, transport, re-use and re-cycling of a container:  raw materials, energy costs, re-cycling costs...

•    The ratio between the cost of a given packaging and the amount of goods it contains: the bigger the container the less raw materials and energy are used per unit of packed goods.

The two options originally considered for the marketing of pasteurised milk, fresh cheese and yoghurts from the Vista Alegre farm dairy were glass and PET or LDPE plastics. In 2021 we added bioplastic for our fresh cheeses. Below, the advantages and disadvantages of each are analysed.  For various reasons, both cardboard and tetra brik were ruled out.


Glass making has a very long history (over several millennia) and has evolved over time. It uses non renewable raw materials. A common formula is 70% silica (SiO2), 20%  sodium carbonate (Na2CO3) to help melt the silica and around 10% calcium carbonate (CaCO3) or lime (CaO) for better durability. Glass may also contain small amounts of magnesium oxide (MgO), iron (III) oxide (Fe2O3) and sulphur trioxide (SO3) due to impurities in silica and lime. Whilst lime and silica are relatively cheap and abundant, sodium carbonate is not, although it can also be produced from salt. Glass can also be made from old glass, in other words, glass can be recycled.

Glass making uses huge quantities of energy as silica must be heated to 1500ºC to reach melting point.

Glass is an inert material and thus a glass container has absolutely no impact on the quality or flavour of the goods it holds, nor on the environment surrounding it. This is one of  the major differences between glass and PET plastic.

Another two big advantages of glass are, firstly, its aptitude for recycling and, in fact, repeated recycling and, secondly, the lower environmental costs of recycling glass rather than manufacturing new glass:
•    glass is 100% recyclable with no limit to the number of times it can be recycled
•    it loses none of its properties when recycled
•    25-32% of the energy spent making new glass is saved when glass is recycled, as old glass reaches melting point at a lower temperature than silica
•    as energy is saved there is less air pollution
•    recycling glass means less rubbish accumulates in dumps: 3000 recycled glass bottles are the equivalent of one ton of glass tipped in dumps
•    3000 recycled glass bottles mean one ton of raw materials are no longer needed to make new glass
•    50% of the energy used to make new glass is saved if 50% recycled glass and 50% new raw materials are used together to make glass

Energy and raw materials needed to produce one ton of glass:

New glass
Recycled glass

Raw materials 1200kg:
%70 silica
100kg ground or

%20 sosa

%10 lime

melting point: 1500ºC
melting point: 900ºC

Recycling requires separation and classification of glass, separation of any unwanted material (bottle tops, labels....), crushing and grinding of glass and melting of the crushed glass with silica, lime and sodium hydroxide (NaOH).

Glass bottles and pots can also be re-used as food and beverage containers, another of their major advantages, although large amounts of water and detergents are needed for optimum cleaning, water becomes polluted and energy is also used.

Two big disadvantages of glass for potting yoghurt or bottling milk should also be mentioned:

•    glass is very heavy, although over the last 15 years the weight of glass bottles has fallen by 40%. A litre glass bottle currently weighs around 380g. Because glass weighs so much, transporting a litre glass bottle of milk, for example, uses more energy per unit of packaging that lighter materials such as plastic. The weight of glass is also an inconvenience for consumers carrying shopping.

•    Glass is very fragile.

It should also be noted that glass does not degrade in nature, except through gradual erosion by, for example, continuous rubbing against other materials in currents of water.


2- PET and LDPE plastics and PLA bioplastics:

PET/LDPE plastics:

Plastic is petrol-based and, as such, a non-renewable raw material that is becoming increasingly scarce. Plastic in general is a synthetic material made through a process called polymerisation. Plastics are therefore synthetic chemical substances called polymers, made up principally of carbon and possessing a macromolecular structure that can be shaped by applying heat or pressure.  

PET plastic in particular is a polyethylene terephthalate polymer produced by polymerisation of terephthalic acid and ethylene glycol. It was first produced in 1941 and has been used to manufacture rigid containers since 1976. LDPE is low density polyethylene and is used to pack food and drinks in bags rather than rigid containers.

Plastic has some advantages for packaging milk and yoghurts:

•    It is very transparent and so the contents of a bottle or pot are easily seen
•    It is very resistant to corrosion, wear and tear, heat and chemicals
•    It is extremely light: a litre bottle made of PET plastic only weighs 40g (28% less than 15 years ago)., whilst a litre bag of LDPE plastic weighs less than 15g
•    It is very hard to break

Additionally, less energy is used to manufacture plastic than almost any other packaging material.

PET and LDPE plastics are recyclable, but for health reasons mechanically recycled plastic is not used to hold food or drinks, basically because of the need to guarantee that no pollutant will be leached from the plastic to a bottle or pots’ contents. Re-used PET and LDPE plastics cannot be used to package food or drinks.


Plastic also has some disadvantages:

•    It needs between 180 and 500 years to degrade naturally, solar radiation being, in fact, the only natural form of degrading plastic. As such, if recycling and re-use are not guaranteed, plastic becomes a pressing problem in terms of environmental pollution due to the huge amounts of rubbish it generates.

•    There are impacts for human health and the environment depending on the amount of stabilisers, flame retardants, pigments and additives included in a PET plastic container.

•    Manufacture and recycling of plastic can release toxic chemical products.

•    There is still a debate as to whether or not plastic is inert as far as the contents of a plastic container are concerned. Although PET plastic is internationally accepted for the packaging of food and beverages and many manufacturers of beverages use PET plastic bottles, the German co-operative Mineral Water Suppliers has clearly stated that it cannot guarantee the inalterability of the flavour of mineral water in recycled bottles, for example. The problem is the amount of acetaldehyde contained in the plastic itself. Acetaldehyde is a colourless, volatile substance that is harmless in health terms but has a fruity smell and can alter the taste of bottled mineral water. The leaching of antimony from the plastic of bottles to their contents is also being researched. The longer a product has been in a plastic container, the higher the risk of leaching.

* Lastly, plastics are becoming a growing environmental hazard due to the lack of awareness of numerous people that throw plastic rubbish in any kind of bin or directly in the countryside, with no regards for their proper management or recycling. The disastrous consequences for wildlife are widely documented.

Bioplastic (PLA)

Bioplastic PLA is defined as plastic derived from starch from plants such as soya, maize or

potatoes. There is still much research into bioplastics, a product that is evolving rapidly.

Bioplastic has certain advantages over petrol-based plastics, although therre are still many

question marks  concerning its environmental and social impacts, related principally to where

and how the plant is cultivated.

Different studies have confirmed that the production of bioplastic releases between 0.8

to 3.2 tons less cabon diooxide than the production of petrol based plastics, but this

depends mainly on the way in which the plants are cultivated (see below).

Bioplastics such as PLA are biodegradable and can therefore be classified as an organic

waste although this characteristic is open to much debate. Thus specific conditions of

temperature and humidity are needed for correct bio-degradation to take place.

Bioplastiics cannot simply be introduced into any organic matter waste collection point.

Because of both its shape and size not all PLA containers or objects can be recycled

and, obviously, becasue the plastic is biodegradable, it has a limited life span.

Whilst it is scientifically proven that components that are negative for our health, move

from petrol-based plastic containers to the foodstuffs they contain, this risk does not

exist with bioplastics. 

However, using crops to produce plastic in a world suffering hunger is very debateable

particularly if crops for bioplastics replace food crops. Research is currently underway to

use crop waste instead of crops themselves: stubble, nutshells or leaves for example.

The way in which the crops are produced is also important, as if cultivation is chemically

intensive, uses GM varieties or heavy farm machinery, por example, the environmental

impacts in soils, the hydrological cycle and even in the plastic itself are very negative.

Bioplastic goods are still expensive as production is limited. However the price is

gradually becoming more competitive, particularly due to rising prices and growing scarcity

of petrol.

One characteristic of bioplastics can be considered as either an advantage or a disad-

vantage: PLA plastic has a shorter life span than PET plastic but this very same fact is

encouraging people to consume fresher products.


3- Conclusions:

Each packaging material has advantages and disadvantages for packaging dairy products:

Plastic Bioplastic (PLA)
Raw materials

non-renewable nor



getting scarce

Renewable, may

compete with

food crops


environmental costs

minimum with correct


Always high

minimum with

correct manage-


Energy costs:

- in manufacturing
very high
lower lower
- in recycling
less than in manufacturing

Not an option for food

Not an option for food

- in transport
higher (due to weight)
lower  lower


light light

Pollution of contents
low but open to debate Considered to be zero

100% for food and drinks
not an option Not an option

Natural degradation
action of water
solar radiation humidity and solar radiation

Human health

- metabolism
no impact
possible impacts No impact
- impact of carrying
very heavy
very light No impact


4- Keys points for evaluating recycling

Recycling has its own advantages and disadvantages. The costs involved are generated during different phases in the process:

•    collection of waste materials: this is clearly related to the distance between where waste is collected and where it is recycled. Thus, the amount of emissions of Greenhouse Gases (GHG) that are saved decrease with an increase in the distance to a recycling plant. However, recycling always saves more GHG than incineration of waste materials.

GHG saved (ton equivalents of carbon per ton of material)

Incineration at 32Km 
Recycling at 32Km
Recycling at 320Km


In the case of  plastic, nearly 0.69 tons of carbon equivalents per ton of plastic can be saved by recycling instead of landfilling and 0.93 would be saved if the plastic were to be recycled instead of being incinerated.

•    classification of materials: separation of different coloured glass or different sorts of plastic, for example
•    Sorting and cleaning the materials: all labels, dirt, caps, etc, have to be removed
•    Recycling itself
•    The costs involved in subsequent distribution

The advantages of recycling are:

•    The emissions of GHG saved when comparing those generated during the extraction and processing of the raw materials used to manufacture new containers and those generated by recycling.
•    GHG saved if containers are recycled instead of incinerated
•    GHG saved if containers are recycled instead of being put into landfill
•    The lower environmental costs (aquatic and acoustic pollution, landscape impacts...) than in the case of extracting new raw materials


5- What container size or capacity?

The smaller a bottle or pot is for milk and yoghurt, the more expensive it becomes in relation to the amount of product it contains. Firstly, more raw materials are used per gram or centilitre of, in this case, yoghurt or milk in small containers, a fact that also represents greater environmental costs (raw materials, energy costs of manufacturing and/or recycling...). Secondly, and logically, the economic cost is also higher per unit of content in smaller containers. For example:

•    Depending on exactly which type of glass pot is chosen, potting 1 litre of yoghurt in several 150ml glass jars costs over the twice as much as using 445ml jars and almost double the cost of using 720ml jars.

•    Bottling a litre of milk in two 500ml glass bottles costs almost twice as much as bottling the same amount of milk in one litre bottle. Almost the same relationship between size and cost are involved if two 500ml PET plastic bottles are used instead of one litre bottle.

Thus, the cost of a container per unit of content is higher for small pots and bottles than for bigger ones.

On the other hand, the fact that big containers obviously weigh more needs to borne in mind, particularly when bottles of milk or pots of yoghurt have to carried home by consumers. Whilst an empty one litre PET plastic bottle weighs 39 grams, an empty one litre glass bottle weighs 360-390g.


6- Size and type of containers used in the Vista Alegre farm dairy:

Our products are sold in containers made of different materials which also vary in size. In each case the aim has been to bear in mind, on the one hand the environmental and economic costs of their manufacture and recycling (and possible re-use) and, on the other, the limitations that given materials and sizes may have for given segments of the consumer population.

Yoghurt:         250ml (220g), 445ml (425g) and 720ml (660g) glass pots

Pasteurised milk:   until november 2018: 1 litre LDPE plastic bags.

                         From November 2018: 1000ml (1 litre) glass bottles and 1000ml plastic PET


The change from plastic bags to bottles, including glass bottles, is due to a firm decision made in 2018 to reduce the amount of plastic used in our packaging. However, about half our customers said they would prefer plastic bottles and that they would not buy milk in glass bottles, a rather disappointing fact. We thus decided to offer both plastic and glass bottles and gradually, hopefully persuade all of our customers to opt for glass bottles. Our first month of sales of milk in glass bottles, November 2018, 55-60% of our customers ended up buying milk in glass bottles.

Feta cheese:        Until 2021: 500g PET plastic tubs. From 2021: PLA plastic tubs

Cheese packaging: greaseproof paper:

We wrap our mature, fine and soft cheeses in a special paper for food stuffs. Why?

* paper can be recycled, is biodegradable and very light

* cheese is not inert, but carries on maturing over time. We do not treat out cheeses with chemicals or wax and thus moulds and yeasts tend to develope on their rind. For this reason if we wrap our cheeses in plastic they may become sticky. The paper we use to wrap our cheeses lets them "breathe" , slowing the appearance of moulds.

* to differentiate our cheeses in the market


Our labels are made of two sorts of material: couche paper for the cheeses wrapped in paper and white polipropilene for the yoghurts, pasteurised milk and fresh cheese (The pasteurised milk label used to be printed directly onto the milk bags). 

Which packaging do we re-use in the dairy?

In our dairy we re-use our yoghurt pots and, from November 2018, our glass milk bottles. Consumer groups and some shops send these back to us and we wash and sterlize them in a special industrial washing tunnel. We give our customers 10cents for each milk bottle they return. As mentioned above, re-using has its own costs: water, energy and time (we check each pot and bottle to make sure it is properly cleaned and rewash if necesssary.... normally due to bits of label or glue stuck on the outside of the pots). In economic terms this process costs almost as much as buying a new pot or bottle, however the process does have important environmental advantages.

We recommend the following in order to facilitate the reuse of yoghurt pots and glass milk bottles:

* remove and do not return lids. These need to be thrown into the appropriate parish recycling bins. If lids are left on after washing they tend to go rusty inside. Additionally, we do not reuse them as they tend to deform and thus not close properly a second time.

* Remove labels from pots or bottles BEFORE beginning to wash them. Then clean the pot or bottle with cold or tepid water to get rid of any bits of labels that might be left. A lot glue tends to be left on the pots or bottles if these are put into a dishwasher or hot washing up water before getting the labels off. 

Do you have any information that could help us improve the type of containers we are using in the Vista Alegre farm dairy? Do you wish to tell us your opinion about the information offered here? Please send your comments.Contact us

Up-dated: April 2021



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