# Evolution of quality characteristics and bacterial community in vacuum-packed soft-shell mud crab during slurry ice cooling and cold storage

## TL;DR

This study shows that slurry ice cooling helps preserve the freshness and flavor of soft-shell mud crabs for up to 7 days.

## Contribution

The study reveals how slurry ice cooling affects biochemical freshness, flavor compounds, and bacterial communities in stored soft-shell mud crabs.

## Key findings

- Crabs remained fresh (K-value < 40%) for 7 days with slurry ice cooling.
- Flavor nucleotides like AMP and IMP declined, reducing umami concentration.
- Bacterial diversity remained stable, but spoilage-related Shewanella increased.

## Abstract

Slurry ice is known to extend the shelf life of refrigerated seafood, yet its specific impact on the quality and microbiota of soft-shell mud crabs during storage has not been well characterized. This study examined changes in the K-value, xanthine oxidase (XOD) activity, free amino acids, flavor nucleotides, and bacterial community succession in the muscle of vacuum-packed soft-shell crabs during slurry ice cooling and cold storage. The results showed that the crabs retained acceptable biochemical freshness (K-value < 40%) for up to 7 days. XOD activity increased over time. Gly, L-Arg, L-Ala, and L-Glu were identified as the predominant FAAs, and their marked reduction significantly influenced flavor development. Adenosine monophosphate was the most abundant flavor nucleotide, followed by inosine monophosphate; the decline in both compounds contributed to a reduction in the equivalent umami concentration. Furthermore, while the α-diversity of the muscle bacterial community remained stable, an increase was observed in four families—primarily Comamonadaceae and Shewanellaceae. Notably, the rise in amplicon sequence variant 936 (ASV936, assigned to Shewanella) by day 7 suggested the onset of spoilage. These findings demonstrate that slurry ice cooling combined with cold storage can effectively maintain the edible quality of soft-shell crabs for 7 days, offering a viable method for short-term preservation.