Mechanistic modelling of the coupled salt and water transport in herring during brining and curing

Microplastic contamination in salt-cured fish and commercial sea salts: an emerging food safety threat in relation to UN Sustainable Development Goals (SDGs)

Microplastic (MP) contamination in seafood, particularly processed varieties like dried and salt-cured fish, poses a significant threat to human health. This study investigated MP levels in 22 salt-cured fish species and commercial sea salts along the Indian east coast. Results showed substantially higher MP concentrations compared to global averages, with fragments and fibres (< 250 µm) composing 70% of identified MPs, primarily PVC and PS polymers (> 55%). Station 2 exhibited high pollution levels, with salt-cured fish averaging 54.06 ± 14.48 MP items/g and salt containing 23.53 ± 4.2 MP items/g, indicating a high hazard risk index. A modest correlation was observed between MP abundance, morphotypes, polymer composition in the salt, and their impact on fish products. Given the critical link between food safety, security, and public health, further research is imperative to mitigate MP contamination, aligning with UN Sustainable Development Goals (Goal 2, Goal 3, Goal 14, and Goal 15) for enhanced food safety and security.

Insight into mechanism of quality changes in tilapia fillets during salting from physicochemical and microstructural perspectives

The effects and mechanisms of salting on quality properties of tilapia fillets were investigated in the present study. Salting under high NaCl concentrations (12 % and 15 %) resulted in low water content and decreased yields, due to the salting-out effects and low pH. Water in fillets increased in the later stage of salting in 3 % and 6 % NaCl solutions (p < 0.05). The released proteins accumulated with increasing time (p < 0.05). The TBARS value increased from 0.01 to 0.20 mg/kg after 10 h in 15 % NaCl solution (p < 0.05). The quality changes were mainly correlated to the shrinking or swelling of myofibers, extracellular spaces, and existential state of muscle proteins. In consideration of fish quality and increasing call for low sodium intake, it was recommended to prepare fillets below 9 % NaCl with short times. The finding provided instructions to obtain target quality properties from tilapia by controlling salting conditions.

Discovering microbiota and volatile compounds of surströmming, the traditional Swedish sour herring

In this study, the microbiota of ready-to-eat surströmming from three Swedish producers were studied using a combined approach. The pH values of the samples ranged between 6.67 ± 0.01 and 6.98 ± 0.01, whereas their a_w values were between 0.911 ± 0.001 and 0.940 ± 0.001. The acetic acid concentration was between 0.289 ± 0.009 g/100 g and 0.556 ± 0.036 g/100 g. Very low concentrations of lactic acid were measured. Viable counting revealed the presence of mesophilic aerobes, mesophilic lactobacilli and lactococci as well as halophilic lactobacilli and lactococci, coagulase-negative staphylococci, halophilic aerobes and anaerobes. Negligible counts for Enterobacteriaceae, Pseudomonadaceae and total eumycetes were observed, whereas no sulfite-reducing anaerobes were detected. Listeria monocytogenes and Salmonella spp. were absent in all samples. Multiplex real-time PCR revealed the absence of the bont/A, bont/B, bont/E, bont/F, and 4gyrB (CP) genes, which encode botulinic toxins, in all the samples analyzed. Metagenomic sequencing revealed the presence of a core microbiota dominated by Halanaerobium praevalens, Alkalibacterium gilvum, Carnobacterium spp., Tetragenococcus halophilus, Clostridiisalibacter spp. and Porphyromonadaceae. Psychrobacter celer, Ruminococcaceae, Marinilactibacillus psychrotolerans, Streptococcus infantis and Salinivibrio costicola were detected as minor OTUs. GC-MS analysis of volatile components revealed the massive presence of trimethylamine and sulphur compounds. Moreover, 1,2,4-trithiolane, phenols, ketones, aldehydes, alcohols, esters and long chain aliphatic hydrocarbons were also detected. The data obtained allowed pro-technological bacteria, which are well-adapted to saline environments, to be discovered for the first time. Further analyses are needed to better clarify the extent of the contribution of either the microbiota or autolytic enzymes of the fish flesh in the aroma definition.