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

Control of abusive water addition to Octopus vulgaris with non‐destructive methods

“…In fact, according to Wells and Wells, the octopus is considerably hyperosmotic compared with the seawater in which it lives, and osmotic uptake over the general body surface is likely. On account of this, octopus is under scrutiny in the media, and doubts regarding abusive incorporation of water that can be considered counterfeiting and result in economic harm for the buyer have been confirmed . Furthermore, previous work has determined that octopus is a very sensitive species and highly susceptible to water uptake if not processed with Good Manufacturing Practices (GMP).…”

World Octopus Fisheries

“…Effects of frozen storage at 18 ºC of O. maya showed no remarkable protein denaturation at the third month of storage and 20% at the firth month, and polyunsaturated fatty acids decreased 6% and 9% at the third and fifth month, respectively (Gullian - Klanian et al, 2017). Recently, some concerns have been raised about the dubious practice by some producers of soaking octopus (O. vulgaris) in fresh water before freezing to increase their weight (Mendes et al, 2017a, b;.…”

“…Traditionally, before cooking and selling, octopus meat was tenderized by repeatedly beating the octopus against hard surfaces, or with wood or metal sticks, but also prolonged heating in boiling water has been applied. These tenderizing procedures have been abandoned with the popularization of freezers, since a freeze-thaw cycle has an equivalent effect (Gleadall et al, 2010;Mendes et al, 2017a). Such methods were always too timeconsuming and energy-demanding for the canning industry, which developed alternative systems such as the addition of small amounts of acid (e.g., vinegar) during the boiling process (Katsanidis, 2004;Katsanidis and Agrafioti, 2009).…”

Quantitation of Water Addition in Octopus Using Time Domain Reflectometry (TDR): Development of a Rapid and Non-Destructive Food Analysis Method

“…Likewise, market studies regarding the addition of water have confirmed these abusive practices [ 10 , 11 ]. A comparative test held in Portugal with 25 commercial samples of prepackaged deep-frozen octopus ( Octopus vulgaris ) showed that most of the products (92%) presented significantly higher moisture and lower protein contents than unprocessed samples, signaling water soaking processing [ 11 ]. In another study with octopus, Mendes et al [ 12 ] also reported artificial weight increases of up to 50.8% and cooking losses, in general, 20% higher than in unprocessed samples.…”

“…Consumers complaints for an enormous weight loss of octopus after cooking lead the media to raise suspicions regarding excessive water addition that could be deemed as adulteration and result in economic fraud for the buyer [8,9]. Likewise, market studies regarding the addition of water have confirmed these abusive practices [10,11]. A comparative test held in Portugal with 25 commercial samples of prepackaged deep-frozen octopus (Octopus vulgaris) showed that most of the products (92%) presented significantly higher moisture and lower protein contents than unprocessed samples, signaling water soaking processing [11].…”