Microbial safety and quality and protein integrity of shrimp sold in shops in Riyadh, Saudi Arabia

The microbial safety and quality were assessed of shrimp from fish shops located in five separate zones in Riyadh City, Saudi Arabia. Protein hydrolysis of the shrimp was determined as a function of microbial growth by using an isoelectric focusing technique. A resuscitation culture step also was assessed and compared with direct plating on selective media for detection of the coliform group and fecal enterococci. The results of this study indicated high (6.23 to 7.23), moderate (4.10 to 5.94), and low (3.49 to 3.94 log CFU/g) ranges of psychrotrophic counts in 23.3, 60, and 16.7% of the samples, respectively. Statistical analysis showed significant (P < 0.05) differences in the psychrotrophic counts among the zones tested, with the highest counts being in the western and central zones, and the lowest counts in the northern zone. Similar results were obtained with coliform, fecal enterococci, and staphylococci counts. Use of the resuscitation step resulted in significantly (P < 0.05) higher recovery of coliforms and fecal enterococci. Band intensities of the sarcoplasmic proteins, as shown in the gel electrophoresis, were faint in samples with higher counts and comparatively intense in the ones with lower counts, indicating a clear relationship between product degradation and microbial load.