Bacterial growth trend of a dried Japanese common squid (Todarodes pacificus Steenstrup) characterised by dehydration

The bacterial contamination of dried Japanese common squid was effectively controlled by regulating the distribution of two water species retained in a Japanese common squid mantle. The two water species were distinguished as water species‐A₁, a mobile‐water species and water species‐A₂, a relatively restricted‐water species. Water species‐A₁ and ‐A₂ were effectively characterised by a physicochemical parameter, the correlation time (τ_C, s), which was evaluated using a proton NMR analysis. The bacterial count was evaluated as a function of τ_C and the relative humidity (RH), and the results precisely demonstrated the existence of a critical τ_C (Cτ_C = 10^?8 s) at which the water species were divided into species‐A₁ (region I < Cτ_C) and ‐A₂ (region II > Cτ_C). Bacterial growth was completely interrupted by species‐A₂ or by an RH lower than 30% (designated as RH₃₀) at <10³ CFU g^?1. In region I, at higher than RH₃₀, the dominant genera of the bacteria observed were identified as Micrococcus and Staphylococcus.     

NaCl diffusion kinetics in dry salting of goat cheese

With the aim of studying diffusion during the dry salting of goat cheese, the experimental profiles of salt and water concentrations were determined in terms of time and distance from the interface. The effective diffusion coefficient was determined using Fick’s Second Law for a semi-infinite model. NaCl was not present at distances greater than 2 cm from the interface after 24 h of salting. The moisture profiles were seen to decrease from the surface farthest from the interface to the zone in contact with the salt. In contrast, salt concentrations were highest at the interface and decreased with distance from this point. The value of the effective diffusion coefficient did not vary significantly with distance from the interface, but did decrease significantly with salting time. Essentially the same phenomenon of salt incorporation was found to occur in dry salting as in brining.