The quality of deep-frozen octopus in the Portuguese retail market: Results from a case study of abusive water addition practices

Octopus spp. are among the most important cephalopod traded. However, consumers frequently complain of excessive reduction of weight/volume, after cooking. A case study in the Portuguese market was held with deep-frozen octopus, being added water and cooking losses evaluated, as well as product's biochemical and microbiological quality. Negative deviations (1.3%–7.7%) to the declared weight were detected in 28% of the products. These shown to be good sources of K, Mg, Cu and Zn and contaminants (Cd, Hg and Pb) were lower than limits. Microbiological quality was generally good though coliform, E. coli, molds and yeasts detected indicate poor hygienic conditions in a number of production facilities. Cephalopod species determined were in accordance with the label in all samples. Most of the products (92%) presented significantly higher moisture and lower protein contents than unprocessed samples, signaling water soaking. Cooking losses were also higher than in unprocessed samples. Overall unconformities were accounted in 80% of the samples, mostly because water was added and not labelled (68%), or because citrates listed as ingredients were not detected. Consumers were shown to be at high risk of being defrauded. New regulations and reference criteria for water addition control need to be enforced.