Effect of thermal processing and canning on cadmium and lead levels in California market squid: the role of metallothioneins

Mineral Content (Essential and Toxic Elements) of Squid Flesh Is Affected by Maceration with Sodium Salts and Vacuum-Cooking

Maceration with sodium salts is applied to irmprove water holding capacity in squid-based products. The aim of this work was to determine how the mineral content of squid flesh is affected by maceration and further vacuum-cooking. Atlantic squids (Loligo vulgaris) from two fisheries (FAO areas No. 47 and 34) were sampled. Macrominerals (g/100 g) present in raw flesh were Na, Mg, P, S, K and Ca, while microminerals accounting for >1 mg/kg were Zn, Si, Sr, Fe, Cu, Al and Mn. As a result of maceration (3 + 1.5% w: w NaCl+ Na citrate) and vacuum-cooking (at 65 °C for 20 min), some squid minerals was removed. The levels of Cd and As were reduced by half, while Na content increased from 0.28 to 0.49 g/100 g. Maceration with sodium salts generally led to minerals leaching (except for Na) with the medium. Further cooking produced additional losses of most of the minerals present in macerated squid (except Pb and Cd). Squid microminerals were hardly removed with the cooking juice. The consumption of macerated-cooked squid covered > 10% of the recommended dietary intake for Na, P, Zn, Mg and Mn, while health risks were almost negligible and mainly concerned Cd (up to 14% of the probable tolerable weekly intake). The combination of both treatments involves certain loss of most of the essential minerals but also contributes to reducing toxicological risks related to mineral intake through squid products.

A Limited Survey of Heavy Metal Concentrations in Fresh and Frozen Cuttlefish Ink and Mantle Used As Food

Cuttlefish ink is consumed as a delicacy worldwide. The current study is the first assessment of heavy metal concentrations in cuttlefish ink versus mantle under different storage methods. A total of 212 samples (64 of fresh mantle, 42 of frozen mantle, 64 of fresh ink, and 42 of frozen ink) were analyzed for the detection of the following heavy metals: arsenic (As), chromium (Cr), iron (Fe), lead (Pb), mercury (Hg), and cadmium (Cd). The median As concentrations were 12.9 mg/kg for fresh mantle, 8.63 mg/kg for frozen mantle, 10.8 mg/kg for frozen ink, and 0.41 mg/kg for fresh ink. The median Cr concentrations were 0.06 mg/kg for fresh mantle and frozen ink, 0.03 mg/kg for frozen mantle, and below the limit of quantification (LOQ) for fresh ink. The median Fe concentrations were 4.08 mg/kg for frozen ink, 1.51 mg/kg for fresh mantle, 0.73 mg/kg for frozen mantle, and below the LOQ for fresh ink. The median Pb concentrations of almost all samples were below the LOQ; only two frozen ink, one fresh ink, one frozen mantle, and one fresh mantle sample exceeded the limit stipulated by the European Union. The Hg concentrations were statistically similar among the four categories of samples; the median Hg concentrations were below the LOQ, and the maximum concentrations were found in frozen ink, at 1.62 mg/kg. The median Cd concentrations were 0.69 mg/kg for frozen ink and 0.11 mg/kg for frozen mantle, fresh mantle and fresh ink concentrations were below the LOQ, and in 11.3% of the tested samples, Cd concentrations were higher than the European Union limit. The probability of samples having a Cd concentration above the legal limit was 35.75 times higher in frozen than in fresh products. Fresh ink had significantly lower concentrations of As, Cr, Fe, and Cd, but the concentrations of Hg and Pb were not significantly different from those of other products. Frozen ink had significantly higher concentrations of Cd, Cr, and Fe, but concentrations of As were lower than those in fresh mantle, pointing out a possible role for the freezing process and for different fishing zones as risk factors for heavy metal contamination.