Indicator Bacteria and Vibrionaceae Multiplication in Post-Harvest Shellstock Oysters

Area of Science:

• Food safety
• Microbiology
• Marine biology

Background:

• Shellstock oysters are a potential vehicle for foodborne illness.
• Indicator bacteria and Vibrionaceae are commonly monitored in seafood.
• Commercial transport and storage conditions can impact microbial safety.

Purpose of the Study:

• To assess the impact of post-harvest handling on microbial load in shellstock oysters.
• To determine the effect of different storage temperatures on indicator bacteria and Vibrionaceae.
• To evaluate the risk associated with commercial oyster transport and storage.

Main Methods:

• Monitoring of aerobic plate counts, fecal coliforms (including Escherichia coli), and Vibrionaceae (including Vibrio cholerae, V. parahaemolyticus, V. vulnificus).
• Incubation of shellstock oysters at 10°C, 22°C, and 30°C during simulated commercial transport and storage.
• Quantification of bacterial levels at various time points.

Main Results:

• Bacterial populations (aerobic plate counts, fecal coliforms, Vibrionaceae) increased significantly at 22°C and 30°C.
• Vibrionaceae growth often occurred independently of fecal coliform increases.
• Storage at 10°C inhibited Vibrio and fecal coliform growth but not Aeromonas hydrophila.

Conclusions:

• Commercial transport and storage at elevated temperatures pose a risk for microbial proliferation in oysters.
• Refrigeration at 10°C is crucial for limiting the growth of key pathogenic bacteria.
• Oyster safety during post-harvest handling requires strict temperature control to mitigate risks.