This post does not deal with using plastic to protect food in transit rather than the plastic used to pre-package food for sale in stores.
Plastic is used to pack food for a number of reasons. The most simple are
- to contain it – to stop it falling about
- protect it from bruising
- wrapping products in plastic reduces moisture loss which helps to keep certain veg fresh for much longer and so prolongs shelf life. This type of packaging is used for root vegetables and cucumbers.
However plastic packaging can be far more sophisticated then that.
Modified Atmosphere Packaging
Wikipedia defines this as the “Re-balancing of gases inside the packaging can be achieved using active techniques such as gas flushing and compensated vacuum or passively by designing “breathable” films known as equilibrium modified atmosphere packaging (EMAP).”
Heres a bit more on these processes
Gas flushing and compensated vacuum techniques
This massively extends the shelf life of fresh food products. Here products are enclosed in a plastic container (the packaging), then the air inside the pack is changed (the modified atmosphere). Basically they actively suck out the oxygen and shove in a gas (you may need to look up those technical terms).
The modification process varies depending on the product. Different amounts of oxygen will be needed and the gas composition will change depending on the food being packed. Red meat needs high oxygen to maintain the red color, bread requires low oxygen to avoid mould and vegetables often need a three-gas mixture. Yum!
A wide variety of products are gas flushed including
- Fresh meat /
Processed meat /
Cheese /
Milk powder
Fresh pasta / Fruit & Vegetables / Ready Meals
Case ready meat / Fresh poultry / Fish & Seafood
Is it Safe? You might want to consider this
The Committee therefore concluded that there is no health concern associated with the use of 0.3%-0.5% CO in a gas mixture with CO2 and N2 as a modified atmosphere packaging gas for fresh meat provided the temperature during storage and transport does not exceed 4°C. However the Committee wishes to point out that, should products be stored under inappropriate conditions, the presence of CO may mask visual evidence of spoilage.
Specially Designed Films
Specially designed plastic films and bags can be used to modify the atmosphere round the product are used. One example is;
“PrimePro® is a packaging technology designed to extend the shelf life of fresh fruits and vegetables. It extends shelf life by removing ethylene gas, a powerful plant hormone that triggers the process of ripening and decay.
PrimePro® is a polyethylene plastic film contains a proprietary additive that is specially designed to remove ethylene from the air around fresh produce.”
Breathable plastics
Unlike most food products, fresh fruits and vegetables continue to respire after they have been harvested. They need some oxygen and will continue to produce carbon dioxide and water vapor. Packaging here has to allow for this. It has to be breathable. There are plastic films that can accommodate that process.
Vacuum packing
This process removes all the oxygen before sealing the plastic container. Here the non breathable impermeable plastic is shrink fitted to the product thereby allowing no contact with the oxygen in the air around it.
Reduction In Food Waste
Plastic packed food means that food can be stored for longer which should reduce food waste. This is often used to justify plastic packaging.
Plastic wrapped food certainly benefits the retailer as it lasts considerably longer on the supermarket shelves giving them a longer sales time. The producers and importers of pre packaged food also benefit from this increased timescale to sell their food.
And yet somehow it hasn’t cut food waste. In fact as a food waste preventive measure it seems remarkably ineffective. For example
“UK retailers and wholesalers are still wasting around 200,000 tonnes of food each year, and when their supply chains are factored in this figure rises to over 4,000,000 tonnes annually.”
or
“Supermarket giant Tesco has revealed it generated almost 30,000 tonnes of food waste in the first six months of 2013. Using its own data and industry-wide figures, it also estimated that across the UK food industry as a whole, 68% of salad to be sold in bags was wasted – 35% of it thrown out by customers.”
Plastic Waste
Of course it rather depends on what you do with food waste and how you define it. If you compost it you return those nutrients to the soil and they are then used to sustain more plants. If you feed it to animals it can be used to make bacon. In fact calling it waste is really rather misleading. It is a resource and is often used as such.
Food waste is biodegradable, plastic waste is not. Food waste can be dealt with locally and if dealt with properly is a resource rather than a waste product. At worst if littered round the environment it will rot away. Plastic waste has to be specially disposed of at proper facilities. If not it will end up as permanent litter.
And thanks to food packaging there is an awful lot of it.
11% of household waste is plastic, 40% of which is plastic bottles, during 2002 plastic bottles worth around £27 million were disposed of at a cost of £45 million
In the UK Waste on line, another government agency, are keen to tell us that we generate 3 million tonnes of plastic waste annually 56% of which is used packaging, three-quarters of which is from households. They estimated that only 7% of total plastic waste is currently being recycled. How Big Is Your Pile
Just A Different Kind Of Waste
Creating a huge pile of plastic waste to prevent food waste does not resolve the waste problem.. It merely shifts it to a different sector.
Packaging & Pre-Portioning
One response to the salad fiasco was to suggest making smaller bags of salad. This is of course another issue with prepackaged food. You can only buy what is there not what you want. Over purchasing obviously leads to increased food waste but is sometimes almost unavoidable. If you only want one pepper buying a three pack is unnecessary and despite good intentions often leads to food waste
Waste & The Consumer
Waste in the home is the responsibility of the purchaser. For sure a wrapped sealed product will last longer but one assumes fresh food was bought to be eaten within a fairly short time scale so the benefits of packaging, in that sense at least, are not so great.
A WRAP report into the subject claims that consumers do not understand how to use packaging specially designed to reduce waste any way. However more education on the subject could help. They also have some interesting observations on consumer attitudes to packaging. See their report Consumer attitudes to food waste and packaging
And we are still throwing away huge amounts and food plus huge amounts of plastic packaging.
Food Safety
Packed food is safer food. Yes, but food can still be stored and kept safely without plastic packaging. Plus There is a considerable body of evidence that chemicals leach from the plastic packaging into the food. Some claim the chemicals in plastic can have adverse effects on health.
There is a consensus of opinion, (though sadly not so much in the way of hard facts), that fruit and vegetables start to loose nutrients once harvested. Plastic packaging certainly slows down the aging process wether it slows down nutrient loss is less clear. But all advice seems to be eat your fruit and veg as fresh as possible. Plastic packaging means you don’t know how old that cucumber is. Wether that is relevant or not I cannot say but s the Committee points out when discussing gas flushing for meat, that unless the meat is stored properly, the presence of CO may mask visual evidence of spoilage.
Conclusions
The issues of food waste, the convenience of pre-packaged, longer-lasting food have to be weighed against environmental costs of plastic; the savings made by being able to store food for longer against the clean up costs for plastic. Bearing in mind that much of the latter is not paid for by the producers but by the end consumer. The supermarket/producer does not pay for the disposal of the plastic wrapper, street cleaning or for the environmental damage it causes when it flies into the canal.
- It uses a lot of resources to plastic wrap food.
- While it might reduce food waste (debateable), it means a huge increase in plastic waste.
- Food waste is biodegradable. Plastic waste is not.
- Plastic rubbish goes on to pollute the environment in many ways.
- It costs a lot of money to treat plastic waste and a lot of plastic waste is food packaging.
- Pre-portioning can actually increase food waste
- There are many hundreds of different plastic used to package food. Many of them are difficult to recycle.
- There is a considerable body of evidence that chemicals leach from the plastic packaging into the food. Some claim the chemicals in plastic can have adverse effects on health.
- You don’t know how old that fruit is. Gas flushing might disguise food rot.
I feel that plastic packing benefits the producers and retailers more than the consumer and the environment. Personally I prefer buying seasonally grown, unpacked food from local suppliers, only buying what you need and eating it as quickly as possible.
- You can read more about the problems with plastic here.
- This useful packaging guide produced by the big retailors
- Wasting Away – how much rubbish we create
Why package produce http://www.bae.ncsu.edu/programs/extension/publicat/postharv/ag-414-8/
http://en.wikipedia.org/wiki/Modified_atmosphere
http://www.modifiedatmospherepackaging.com
