Samuel Kwawukume

High oxygen‐permeable vacuum skin packaging (10K VSP) is widely used for frozen seafood distribution to mitigate anaerobic pathogen risks, yet post‐thaw microbial dynamics during refrigerated display remain poorly characterized. This study evaluated post‐thaw microbial quality and bacterial community succession across 10 commercially frozen‐then‐thawed seafood species held under simulated retail refrigeration (4°C) on Days 1, 5, and 9. Aerobic plate counts, lactic acid bacteria, and coliform/ Escherichia coli indicator counts were determined, and bacterial communities were characterized using high‐throughput 16S rRNA gene sequencing. Average aerobic plate counts increased from 3.57 ± 1.03 log CFU/g on Day 1 to 6.00 ± 0.84 log CFU/g on Day 5 and 7.30 ± 0.64 log CFU/g on Day 9, although growth patterns differed among seafood products. Several products reached or exceeded microbial acceptability limits by Day 5 or Day 9. Sequencing revealed an ecological transition from initial Photobacterium and Psychrobacter dominance to a shift toward spoilage‐associated genera, particularly Pseudomonas and Brochothrix , during refrigerated storage under the tested oxygen‐permeable VSP condition. These findings provide study‐specific information on post‐thaw microbial changes in 10K VSP seafood products that may help inform future refrigerated handling and display recommendations.

Vacuum skin packaging (VSP) has emerged as an innovative solution to enhance the safety and freshness of seafood and extend the shelf life of food products. However, its efficacy on seafood products remains completely underexplored. This study aims to evaluate the shelf life and characterize the microbial community dynamics of 10 oxygen permeable skin packed seafood products during refrigeration. Vacuum skin-packed flounder, mahi, perch, salmon, scallop, shrimp, snapper, swai, tilapia, and tuna were collected from a seafood processor in Florida. Samples were defrosted at 4°C and evaluated on days 1, 5, and 9 for aerobic, coliform, and lactic acid bacteria counts. Microbial DNA from samples was extracted and used to characterize bacterial community dynamics during storage. The sequencing data were analyzed using the CLC Genomics Workbench. On day 1, the average aerobic plate count for all 10 samples was 3.5 log CFU/g, which increased to 6 log CFU/g by day 5 and reached 7.5 log CFU/g by day 9. The overall enumeration data indicate that the seafood samples exceeded the spoilage thresholds established by the FDA and FAO by day 5 under refrigeration. Sequencing data revealed Photobacterium, Psychrobacter, Pseudomonas, and Brochothrix as the dominant bacterial genera across most seafood species. Notably, Pseudomonas emerged as the predominant genus by day 5, surpassing all other bacterial genera in abundance. These data provide evidence-based refrigerated handling guidance for oxygen-permeable VSP seafood that processors and retailers can use to manage display time, thereby reducing spoilage-related losses and protecting consumers.

In the United States, testing data indicate that up to 30% of shrimp sold are misrepresented. Among species harvested from U.S. waters, royal red shrimp (Pleoticus robustus) is one of the most valued and is therefore frequently substituted with Argentine red shrimp (Pleoticus muelleri). This study developed and validated an RNase H‑dependent polymerase chain reaction (rhPCR) assay to accurately distinguish P. robustus from P. muelleri. Primer pairs targeting the COI gene were designed, screened for specificity, and subsequently converted into RNase H2‑activated primers labeled with FAM and biotin for lateral‑flow detection. The optimized assay was validated using genomic and crude DNA extracted from 65 barcoded shrimp tissue samples representing seven commercially relevant species: L. setiferus, L. vannamei, P. aztecus, P. duorarum, P. monodon, P. muelleri, and P. robustus. To assess real‑world performance, the assay was further applied to 20 blinded retail samples marketed as royal red shrimp and collected by a state food‑safety division. Results revealed a 60% species‑substitution rate, with 30% of samples identified as P. muelleri, demonstrating the assay’s effectiveness for detecting mislabeling in commercial products. The assay achieved 100% specificity, correctly differentiating royal red and Argentine red shrimp from all non‑target species. Analytical sensitivity reached 0.1 ng/µL for P. robustus and 0.01 ng/µL for P. muelleri crude DNA, with a total turnaround time of 150 minutes for processing 20 samples. These assays provide enforcement agencies with a robust, field‑deployable method for detecting royal red shrimp substitution and supporting evidence‑based regulatory decisions.