A shipment of frozen fish arrives at your food establishment. you see that the outside bottoms of the shipping cartons have too much ice and the fish fillets held within the cartons have brown edges. these are signs of:

Excess browning at the edges, ice formation at the bottoms of the containers, and are indicators of thawing and refreezing. While in standard at-home practice of refreezing thawed fish is acceptable, it is not during shipping because it is impossible to tell how long the fish were kept out of a cold environment and may transmit disease (plus, visible damage to the fish decreases salability).