Pre-packed products require an indication of mass or volume
Most of the food bought in the supermarket is sold in packages. To protect the interest of the consumers these prepackage need to express the quantity, volume and/or mass of the product that is sold. In general, the volume needs to be indicated for liquid products and for all other products there needs to be an indication of the product ́s mass number. For example, on pre-packed meat, the number of grams is indicated and milk has an indication in litres. This way the consumer knows how much he is buying for a certain price. These expressions are mandatory according to Directive 76/211/EEC on pre-packed products. Detailed guidance on these requirements for pre-packages is given in other documents such as OIML Recommendations79and 87.
Expressions of mass on pre-packaging are better than volume
Where liquids require an indication of the volume when sold in prepackages, this is not the optimal indicator. For consumer protection reasons an expression of the mass is better.
First of all, measurement instrumentation used for mass is under legal control such as mandatory periodic re-verification whilst the instrumentation used for length, volume and number is not. This legal control provides more guarantees with the measuring instrument functions correctly.
Moreover, selling on mass is to be preferred as each molecule has its own mass. This avoids misunderstandings caused by aeration of the product, influences of temperature changes and, where partially gasses are involved, pressure. Apart from that, when the contents are declared in units of volume, a reference temperature of 20° C is obligatory. In a way, a volume reference is misleading for liquids usually served cold, such as dairy products, beers and sodas.
Additionally, weighing equipment is more accurate than measuring equipment for volume.
For the reasons above CECIP believes that expressions of mass on pre-packaging are better than expressions of volume.
Mass indications on all pre-packed products improves consumer protection
CECIP is convinced that to provide the most reliable, accurate and realistic indication of the product an expression of mass should be included on the prepackaged. By doing this the consumer is better informed about the product he or she is buying. However, this doesn’t mean the volume indication needs to be removed as that it is still possible to express the volume next to the mass.
To improve consumer protection, changes to Directive 76/211/EEC, OIML Recommendation 79 and WELMEC guides are necessary. Therefore, CECIP calls on all relevant stakeholders such as the European Commission and national authorities to improve the consumer protection and request expression of mass on all prepackages.