Why can't PET bottles be reused?

Reusable PET beverage bottles

Author: Martin Heimrich - Bavarian State Office for Health and Food Safety

PET beverage bottles are currently very popular.
You can find them at work, at school and in any leisure activity.

How long has the PET beverage bottle been around?

The first returnable PET bottle (PET = polyethylene terephthalate) was brought onto the German market in 1990 by Coca Cola. However, this plastic tended to release acetaldehyde, a degradation product of PET, into the contents and thus impair the taste and smell of the contents of the bottle. For this reason, only flavored drinks were initially bottled in it. Only with improved raw materials and new technology could carbonated mineral water be offered in PET bottles almost ten years later.

In the case of products filled in PET, the acetaldehyde value is now usually well below the sensory limit value of 5 micrograms and is therefore no longer noticeable. Acetaldehyde is also a natural component of e.g. B. fruits, wine, cheese, butter and white bread. The content in these foods is many times higher than the amount that can still be sensed in the mineral water.

Do PET bottles have advantages over glass bottles?

PET bottles are light, stable, transparent and practically unbreakable. Due to their low weight, PET bottles have clear ecological advantages over glass bottles, especially in the reusable system. In today's reusable PET bottles for soft drinks, the packaging makes up less than 7 percent of the total weight. In addition, PET is 100 percent recyclable.

Glass is inert, does not interact with the product, is also fully reusable and 100% recyclable.

In contrast to glass bottles, PET bottles can release residual monomers, additives and other components into the product.

How are reusable PET bottles treated before refilling?

A reusable plastic bottle is usually filled up to 25 times and delivered to retailers before it is discarded.

In every reusable system (with PET as with glass), returning bottles must be checked carefully. Contaminated or mechanically damaged bottles are sorted out and sent for recycling. All intact containers are stripped of their old labels and thoroughly hygienically cleaned in several cleaning processes at more than 60ºC. A special computer nose, a so-called "sniffer", is used today in a bottle washing line to control and sort out contaminated returnable plastic bottles. This is a machine that recognizes smells known to you and sorts out any bottles that are contaminated before filling.

What is to be considered?

Particularly with PET bottles, interactions between the bottle and the filled product must be taken into account. Many carefree consumers store or dilute cleaning agents, mineral oil products or chemical products such as paints or solvents in reusable PET bottles. But foreign food is also filled into empty PET bottles. Such residues cannot be completely removed by the washing process then carried out at the bottler, since they diffuse into the material or adhere to the plastic surface. If the "sniffer" does not recognize foreign smells, these bottles are refilled. For example, a production process for "slush ice" for private households is described on the Internet. You need an empty plastic bottle for this. If such a misappropriated PET mineral water bottle is returned, the next consumer can receive a fruity-flavored mineral water, because the "sniffer" may not yet know this new aroma.

Mineral waters with conspicuous taste often end up as a complaint test at the official food inspection. Here, the cause of odor and taste deviations is investigated, sometimes with a great deal of analytical effort. The garlic note from a dressing prepared in a reusable PET bottle was also found in the mineral water.

What can the consumer do?

PET returnable bottles should never be used for other purposes and then returned.

How can you recognize reusable bottles?

The word “reusable” is generally written on the bottles. This applies to both glass and PET bottles.
Reusable bottles can often be recognized by the Blue Angel eco-label or the reusable symbol of the associations of the German beverage industry.


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