Fresh and frozen seafood products (fish, shellfish, crustaceans, molluscs) in wide use in Croatia and typical of the Mediterranean diet, were examined for the presence of microbiological contamination through the winter and summer seasons. Total bacterial counts of aerobic mesophilic bacteria (AB), aerobic psychrophilic bacteria (AP), Salmonella spp., Enterobacteriaceae, Escherichia coli, Staphylococcus aureus, sulphite-reducing clostridia (SRC), Listeria monocytogenes, Vibrio cholerae and V. parahaemolyticus were measured. The microbiological quality of individual samples varied widely between animal species and also between winter/summer seasons regarding total counts of aerobic mesophilic and psychrophilic bacteria. The poorest quality was for (both summer and winter) fish samples, where 66.6 % of fresh and frozen fish were found unacceptable by Croatian standards. The overall prevalence of V. parahaemolyticus was 5%. Its recovery rate was higher in fresh/ frozen shellfish in both seasons than in other specimens or other storage/season conditions. Fresh crustaceans sampled in winter demonstrated significantly higher aerobic mesophilic counts than frozen ones. Unacceptable Enterobacteriaceae levels were obtained in 40% of the fresh fish summer samples. The results of this survey constitute an indicator of bacteriological contamination of a variety of seafood. The findings could serve as a basis for future testing of seafood, and possibly as a template for developing a regional/Mediterranean testing scheme on the microbial contamination of seafood in order to establish data with comparative epidemiological and statistical values.

The ability of two commercial rapid identification systems, API 20E and BBL Crystal E/NF, to reliably identify bacterial isolates from the internal organs of reared sea bass were compared. The tests gave different results: API 20E identified bacteria as Pseudomonas spp. with 37% accuracy, while BBL Crystal E/NF identified them as Flavobacterium odoratum with 99% accuracy. Although F. odoratum is not a marine fish pathogen, conventional tests conducted with the same isolates were more indicative of them being Flavobacterium spp. than Pseudomonas spp., suggesting that BBL Crystal E/NF was more reliable in this identification. Both systems were found to be applicable for diagnostics of marine fish pathogens, but should be used with caution because of possible misinterpretation.

In our study, we assessed whether the addition of basil, fennel, oregano, rosemary, and chili can improve oxidative stability and sensory properties of flaxseed oil (FO) during 180 days of storage or induce oil contamination by microorganisms. Results showed that addition of spices and herbs in FO affected the hydrolytic changes, but far less than 2% of free fatty acids after storage, which was in line with regulations. Further, the addition of spices and herbs in FO decreased peroxide value (even up to 68.7% in FO with oregano) vs. FO whose value increased during storage, indicating increased oxidative stability and prolongation of shelf life of infused oils. The antioxidant activity of the infused oils ranged from 56.40% to 97.66%. In addition, the phenol content was higher in all infused oils (6.81–22.92 mg/kg) vs. FO (5.44 mg/kg), indicating that herbs and spices could scavenge free radicals and inhibit lipid peroxidation, while sensory analysts showed that FO infused with chili had the lowest bitterness intensity. According to the presence of certain microorganisms, results highlighted the need to develop new methods for inactivating microorganisms that would not only provide a microbial safety, but also preserve the beneficial properties of the oils/products.

Listeria monocytogenes is a bacterium widespread in the environment, which has a capacity to survive and grow under various conditions. The bacterial growth results from interactions when subjected to various temperatures, pH levels, and NaCl concentrations were examined by measurements and predictive modelling. Good correlation across the range of growth conditions was shown among observed and predicted growth values, having similar trends and minimal defl ections for pH levels 5.0 and 6.0. The growth condition in the 8% NaCl concentration (pH 7.0, temperature 4 °C) resulted with a growth curve of 1 log interval greater than the fi tted curve for all the measurements. In all of the cases, there were consistent increases in the rates and decreases in the lag time when the growth temperature increased. Higher incubation temperatures provided higher growth rates as 30 °C and 35 °C yielded double increase of the fi tted rate. Fitted and measured growth rates for salinity conditions were signifi cantly different (P<0.05). Comparison of doubling times showed good compatibility, particularly at lower temperatures. Critical use of a model is suggested, although it may enable microbiologists to limit the need of challenge tests and to make rapid and realistic prediction of the growth of L. monocytogenes under conditions relevant to a range of aquatic and other products examined.