In the US much of the enforcement of weights and measures is at the state level, however most states have adopted NIST Handbook 133 as the basis of their net weight control systems. Most companies design net weight control systems so that sampling of the product by state agencies in the field will not result in violations when the testing methods in handbook 133 are applied. A common approach to this is to require that a lot averages the label stated weight with no containers below the maximum allowable variance (MAV) as defined in NIST handbook 133. Since most inspection look at a small subset of a production lot there is still the possibility of being below the label weight in the average of a small sample so some people adjust targets to give a higher confidence that any random sample of 10 units will average above the lsw. Of course, this increases the overfill and thus the cost of the product so many companies accept the risk of the occasional fine for a weight violation to avoided this overfill because it is more economical in the long run.
Here is a link to handbook 133 http://www.nist.gov/...bs/hb133-11.cfm
Dear williamw,
Many thanks for this compilation. The document contains a lot of rare and useful information.
My only criticism is that for
frozen seafood, either ice-block encased or IQF, the proposed sampling plans for net weight determination are IMEX out of touch with (quantity) reality. The net weight procedures are also in some aspects highly debatable IMO, and in others unworkable for certain types of product (this possibility is indicated in the text).
I'm not suggesting that fully satisfactory, alternative solutions for general use are readily available to the above comments, far from it. It's a tricky topic, both conceptually and compliance-wise.
Rgds / Charles.C