Shelf Life

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Changed on: 05.04.2017

The fact that a food product may have passed its best-before, freshness or shelf-life date does not mean that the product cannot be eaten anymore.

Manufacturers guarantee that a product keeps its full edibility up this point of time when stored correctly; this is only possible if the product maintains its actual edibility for a longer period.
In other words, food products usually last longer than the best-before or freshness date provided. However, it is often difficult to tell how much longer, as it depends on the product in question and also its storage up to this point in time.

If a rough examination using our senses (colour, visual appearance and odour) does not find anything unusual or suspicious and the timeframe between the period the product has exceeded the best-before or freshness date and the actual shelf life is short, then there is no reason not to eat the product.

This is a significant difference to products featuring a so-called expiry dates ("zu verbrauchen bis"). An expiry date is carried by easily perishable goods that contain microorganisms.

A product that has exceeded its expiry date is not considered to be safe anymore. Such a product should not be eaten and be immediately disposed of.

The fact that a food product may have passed its best-before, freshness or shelf-life date does not mean that the product cannot be eaten anymore.

Manufacturers guarantee that a product keeps its full edibility up this point of time when stored correctly; this is only possible if the product maintains its actual edibility for a longer period.
In other words, food products usually last longer than the best-before or freshness date provided. However, it is often difficult to tell how much longer, as it depends on the product in question and also its storage up to this point in time.

If a rough examination using our senses (colour, visual appearance and odour) does not find anything unusual or suspicious and the timeframe between the period the product has exceeded the best-before or freshness date and the actual shelf life is short, then there is no reason not to eat the product.

This is a significant difference to products featuring a so-called expiry dates ("zu verbrauchen bis"). An expiry date is carried by easily perishable goods that contain microorganisms.

A product that has exceeded its expiry date is not considered to be safe anymore. Such a product should not be eaten and be immediately disposed of.

Food Irradiation

Method

Food irradiation is a physical preservation method using ionising radiation. Electrons or gamma radiation from the radioactive decay of Cobalt-60 are typically used as ionising radiation. However, the food will not become radioactive when subjected to this kind of radiation.

Treatment with ionising radiation kills microorganisms and delays ripening und germination processes, thus, prolonging shelf life.

Method

Food irradiation is a physical preservation method using ionising radiation. Electrons or gamma radiation from the radioactive decay of Cobalt-60 are typically used as ionising radiation. However, the food will not become radioactive when subjected to this kind of radiation.

Treatment with ionising radiation kills microorganisms and delays ripening und germination processes, thus, prolonging shelf life.

Legal Regulations

Legal Regulations

The legal basis for food irradiation is regulated in §9 of the Austrian Food Safety and Consumer Protection Act. It states that it is prohibited to treat food with ionising irradiation or place it on the market without official permission.

Food irradiation is regulated at EU levels in the Framework Directive 1999/2/EC (defines labelling, among other subjects) and Community Directive 1999/3/EC (contains the list of products permitted to be treated with irradiation in the EU). Only dried aromatic herbs and spices may be treated using irradiation in Austria, in accordance with EU Directive 1999/3/EC. There are national permits for any other food products in Austria, while various foods may be treated using irradiation in other countries. Food treated with irradiation must be labelled as "bestrahlt" (irradiated) or "mit ionisierenden Strahlen behandelt" (treated with ionising irradiation).

Detection Methods

Detection Methods

Checking for evidence of food irradiation is done either on frozen excited charge-transfer states or on radical species, formed during irradiation and by decay products. The various analysis methods are described in the following paragraphs.

Luminescence Measurements

These methods are based on charge carriers of mineral impurities -- e.g. traces of soil excited by the irradiation. The charge carriers will go back to their original state by adding energy (heat or light). This causes luminescence which is measured. This includes photostimulated luminescence (PSL), a rapid screening method, and the more elaborate thermoluminescence (TL) method, used for test assurance. Fields of application include spices and tea.

Electron Spin Resonance (ESR)

When treated with irradiation, crystalline structures (bone, shells, etc. in animal products or crystalline cellulose and sugar in plant products) form stable radicals. These radicals absorb microwave radiation in a magnetic field. This method is used to examine poultry, lamb, fish and shellfish, nuts, berries, etc.

Gas Chromatography Mass Spectrometry (GC-MS) of Fat Radiolysis Products

During the irradiation of foods containing fat, the radicals formed lead to the creation of 2-alkylcyclobutanons, which are radiation-specific marker substances and can be detected using GC-MS analysis in the headspace sample. This method is used for meat and fish samples, for instance.

Examinations

Examinations

The Group "Contamination and Special Analytics" is Austria’s sole institute conducting routine examinations on food irradiation. It uses a variety of special equipment enabling it to apply all the methods mentioned above.

Official food inspections test a variety of foods, such as spices, herbal tea, instant soup, poultry, fish, shellfish and crustaceans, etc. to determine whether irradiated herbs or spices have been labelled properly or whether other foods have been illegally treated using irradiation.
We also offer services in the field of special analytics to private clients from production and retail, as well as to other laboratories.

Analysis Results 2013

More than 100 samples of mainly spices, instant soup and shellfish were examined in 2013. The following chart shows which and how many samples were analysed using what methods in detail.

The use of irradiation could be confirmed in eight samples (7.5 %) of a total of 106 samples, the majority of which were instant soup (see chart on the left).


Contact

Dr. Christoph Czerwenka
Phone: +43 50 555-32531
Spargelfeldstraße 191
1220 Wien



Dr. Christoph Czerwenka
Phone: +43 50 555-32531
Spargelfeldstraße 191
1220 Wien



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