Chemical, microbiological, and sensory quality of cod products salted in different brines

Abstract

Studies were carried out on the effect of different brines containing high concentrations of calcium chloride (CaCl2, 0.8%w/w), magnesium chloride (MgCl2, 0.4%w/w), and potassium chloride (KCl, 50%) on the chemical (chloride and moisture contents), microbial (total viable counts, total coliforms, enterococci, and staphylococci), and sensory quality of salted cod. The brines were prepared from combinations of the Ca, Mg, and K ions and sodium chloride (NaCl) at pH 6.5 and 8.5. Additionally, 3 salts (one composed solely of NaCl, another commercial sea salt from the southern Europe and, finally, a natural salt from northern Europe) were also tested. Principal component analysis structured the chemical and microbiology data in 3 clusters: (1) an extreme cluster, formed by cod brined in the commercial sea salt, which achieved the highest microbiological counts, namely 4.1 log CFU/g on plate count agar (PCA) and 1250 coliforms/g; (2) an intermediate cluster composed of cod salted in brine containing 50% NaCl, 0.4% MgCl2, and 49.6% KCl (pH 6.5); and (3) a central cluster, including all the other treatments, which presented the lowest microbiological counts, namely 2.4 log CFU/g on PCA and 20 coliforrns/g. Although the batches of the intermediate cluster presented slightly higher total viable and staphylococci counts than the central cluster, the presence of Mg and K ions improved the color of the salted product. In the assayed concentrations, CaCl2, MgCl2, and KCl can be used in the brining of cod without adversely affecting the microbiological and sensory quality of the salted cod.