The Effects of Short-Time Temperature Abuse on the Microbial and Sensory Quality of Chilled Saithe (Pollachius virens) Fillets

Factors affecting the quality of frozen large yellow croaker (Pseudosciaena crocea) in cold chain logistics: Retention time and temperature fluctuation

The purpose of this study is to provide a reference for avoiding the quality loss of large yellow croaker in cold chain transportation. The effects of retention time before freezing and temperature fluctuation caused by transshipment in logistics were evaluated by TVB-N, K value, TMA value, BAs, FAAs content and protein-related characteristics. The results showed that the retention would lead to the rapid increase of TVB-N, K value, and TMA value. And the temperature fluctuation would further lead to deterioration of these indicators. We concluded that the influence of retention time was far greater than that of temperature fluctuation. In addition, the bitter free amino acids (FAAs) were highly correlated with the freshness-related indicators, which could reflect the freshness changes of samples, especially the quantity of histidine. Therefore, it is suggested to freeze samples immediately after catching and try to avoid temperature fluctuations during cold chain to maintain the quality.

Freshness Assessment and Shelf-Life Prediction for Seriola dumerili from Aquaculture Based on the Quality Index Method

Fish and fish-based products are easily perishable foods due to different factors, including fragile organization, abundant endo-enzymes, psychrophilic bacteria, and impact of pre-harvest operations, that contribute to reducing its value. Therefore, a timely effective method for fish freshness and shelf-life evaluation is important. In this context, this study aimed to develop a sensory scheme based on the Quality Index Method (QIM) (sensory table and point system) for freshness monitorization and shelf-life prediction for Seriola dumerili from aquaculture in Madeira Island. Evaluation of appearance, texture, eyes, and gills was performed during 20 days of storage on ice (0 ± 1 °C). The shelf-life prediction was supported by the analysis of microorganisms (total viable colonies, TVC, counts), texture (Torrymeter), and production of trimethylamine (TMA), evaluated by HS-SPME–GC–MS and validated according to Association of Official Analytical Chemists AOAC guidelines. The result is a QIM scheme with 25 demerit points, where zero indicates total freshness. From the integration of sensory analysis, microbial growth at the time of rejection (TVC, 10⁸ cfu/cm² and H2S producers, 10⁷ cfu/cm²), texture (Torrymeter value < 8), and TMA analyses (>12.5 mg/100 g), shelf-life was estimated as 12 days (±0.5 days). The obtained results show the high-throughput potential of the developed method for fish freshness assessment and shelf-life prediction. This QIM scheme is a secure way to measure quality and provide users with a reliable standardized fish freshness measure.