How to Ensure the Correct Weight
A key requirement to ensuring conformity of packaged food is that all products are as accurate in weight as possible to advertised values. In this blog, we look at weight compliance requirements, how manufacturers can consistently meet these and the business benefits of precision weighing.
Unravelling Compliance Requirements
Overall, weight regulations aim to protect consumers against short weight or measures. Regulations differ slightly depending on country. In the UK, the Weights and Measures (Packaged Goods) Regulations 2006 stipulate three main rules:
- The actual contents of the packages should not be less, on average, than the nominal quantity.
- The proportion of packages which are short of the stated quantity by a defined amount (the Tolerable Negative Error (TNE) should be less than a specified level.
- No package should be short by more than twice the TNE.
In Europe, the onus to comply with the Measuring Instruments Directive (MID) rests with the checkweighing supplier. The regulation covers the exact production and performance requirements of the checkweigher at purchase stage to legal verification on installation. This ensures that manufacturers only purchase high quality weighing instruments. Following installation, the manufacturer must check ongoing compliance with local Weights and Measures standards.
The Food and Drug Administration (FDA) in the US has no minimum weight restriction on food packaging. However, it will consider a product misbranded unless the label accurately reflects the content in terms of weight, measure, or numerical count.
Ensuring Precision Weighing
The only technology which ensures compliance with weights and measures regulations is a checkweigher. This type of product inspection system works by weighing each packaged product in real time, classifying all items by pre-set weight parameters and rejecting any non-conforming goods for further investigation.
To ensure that the checkweigher is fully optimised, the system must be regularly checked with test samples. It is also vital that all products are stable when presented to the checkweigher, as any vibrations or movements will affect weighing accuracy. Transfer solutions, such as guide rails or sidegrip belts, stabilise products.
For full regulatory compliance, each product must be presented to the checkweigher individually. Spacing or timing conveyors are used to create a gap between packs, thereby optimising the weighing process for manufacturers with multiple products and/or numerous lanes. To complement fast production line speeds, the conveyors speed up the individual products through the checkweigher.
Benefiting from Verifying Product Weight
The primary reason for integrating a checkweigher is to comply with weight regulations and supplier agreements. Compliance will facilitate trade in certain markets. However, precision weighing brings an abundance of additional business benefits:
- Avoids product recalls and associated costs and repercussions.
- Helps ensure customer satisfaction and protect brand reputation from underfill product.
- Enhances productivity and saves costs by measuring and reporting production line efficiency. For example: an optional feedback feature on checkweighers detects deviations away from the target content weight and automatically adjusts filling machines located further up the line.
- Protects bottom-line profits by reworking overfill product. For example, if a manufacturer reduced the overfilling of 450 gram packs by 1 gram, produced at a throughput rate of 200 packs per minute, 16 hours a day, this could potentially save €28,000+ worth of product each year.
- Proves due diligence to authorities through real time monitoring and reporting of all product inspection activity including production counts, batch tracking and weight.
- Facilitates lot quantity checking by regulators. An Action Counter software option can reject a pre-defined number of accepted products for further scrutiny. This is achieved without stopping or slowing down the production process.
To help manufacturers achieve further product conformity requirements, such as inspecting for contaminants and product/packaging integrity checks, checkweighing technology can combine with metal detection, x-ray or vision inspection in one machine. Combination inspection systems will also improve production line efficiencies and overcome production space constraints.
To discover how packaged food manufacturers can achieve conformity, please read our white paper ‘Ensuring Conformity of Packaged Food’. For more information about checkweighers, simply download ‘The Checkweighing Guide’.
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