Frozen Seafood Products Determination of Net Weight

Glazing on the surface of food is an ice treatment to protect the product right after the freezing as the cold environment temperature damages the surface of the product. Glazing rate as 3-5% is called as "Protection glaze" but for long term storages this rate may not be sufficient. For this reason, the products with more than 1 year of shelf life need higher glazing rate. But today, it is seen that with glazing treatment which has become a sector trick, the product size notified to the consumer decreases by 10-20% when the product is thawed and the water rate reaches to 40-50%.

As Denizer, we treat max. 20% glazing rate on our products and notify our customers about the real size of the product. In order to calculate the net weight of the product, we accept AOAC (Association of Official Agricultural Chemists) standards that accepted by all around the world.

AOAC net weight calculation standards for water products are as following;

*AOAC Official Method 963.26 Net Contents of Frozen Food Containers-Unglazed Foods

Apparatus

> For packages up to 5 pounds (2.27 kg), use scale of adequate capacity with sensitivity of 0.01 oz. (0.28 g).
> For packages over 5 pounds (2.27 kg), use scale of adequate capacity with sensitivity of 0.025 oz. (0-71 g).

Procedure

Set scale on firm support and level. Adjust 0 load indicator or rest point and check sensitivity. Remove package from low temperature storage, remove frost and ice from outside of package, and weigh immediately (W). Open package; remove contents, including any product particles and frost crystals. Air-dry empty package at room temperature and weigh (E). Weight of contents=W-E.

* AOAC Official Method 963.18 Net Contents of Frozen Seafoods Glazed Foods

Set scale, -963.26A (see 42.3.01) on firm support and level. Adjust 0 load indicator or rest point and check sensitivity.

Remove package from low temperature storage, open immediately and place contents under gentle spray of cold water. Agitate carefully so product is not broken. Spray until all ice glaze that can be seen or felt is removed. Transfer product to circular No. 8 sieve, 20 cm (8”) diameter for packages #0.9 kg (2 lb) and 30 cm (12”) for packages >0.9 kg (2 lb). Without shifting product, incline sieve at angle of 17-20E to facilitate drainage and drain exactly 2 min. (stopwatch). Immediately transfer product to tared pan (B) and weigh (A). Weight of product=A-B.

* AOAC Official Method 967.13 Drained Weight of Frozen Shrimp and Crabmeat

Apparatus

> Container - Wire mesh basket large enough to hold contents of one package and with openings small enough to retain all pieces. Expanded metal test-tube basket or equivalent, fully lined with standard 16 mesh per linear inch (2.54 cm) insect screen is satisfactory.
> Balance - Sensitive to 0.25 g or 0.01 oz.
> Sieves - U.S. No. 8, 20 cm (8”) and 30 cm (12”).

Determination

> Place contents of individual package in wire mesh basket and immerse in 15 L (4-gal.) container of fresh water at 26 ± 3ºC (80 ± 5ºF) so that top of basket extends above water level. Introduce water of same temperature at bottom of container at flow rate of 4-11 L (1-3 gal.)/min. As soon as product thaws, as determined by loss of rigidity, transfer all material to 30 cm (12”) (for packages 450 g [1 lb.]), or 20 cm (8”) (for packages ≤450 g [1 lb.]) No. 8 sieve, distributing evenly. Without shifting material on sieve, incline sieve to ca 30º from horizontal to facilitate drainage. Two minutes from time placed on sieved, transfer product to previously weighed pan, and weigh. Weight so found minus weight of pan is drained weight of product.