Microbiological Evaluation of Shrimp ( Pandalus borealis ) Processing.

Area of Science:

• Food Microbiology
• Seafood Science
• Microbial Ecology

Background:

• Shrimp (Pandalus borealis) are a significant seafood commodity.
• Microbiological quality is crucial for seafood safety and shelf-life.
• Understanding microbial dynamics during processing is essential for quality control.

Purpose of the Study:

• To assess the microbiological quality of shrimp across three distinct processing lines in Maine.
• To identify critical control points for microbial contamination and reduction during shrimp processing.
• To evaluate the effectiveness of different processing steps on aerobic plate count (APC) and salt-requiring (SR) organisms.

Main Methods:

• Sampling of shrimp at various stages of three processing lines: brine-cooked shell-on, hand-peeled raw, and machine-peeled cooked.
• Microbiological analysis using Plate Count Agar for APC and Salt Water Medium for SR organisms.
• Quantification of psychrotrophic-mesophilic flora, coliforms, and coagulase-positive staphylococci.

Main Results:

• Freshly caught shrimp had low APC but high SR organism counts (1.11 × 10^5/g).
• Cooking significantly reduced SR flora, but counts increased post-handling in the brine-cooked line.
• Hand-peeling and machine-peeled cooking processes showed reductions in bacterial loads, but final counts remained significant (approx. 4 × 10^4/g).
• Low levels of coliforms and coagulase-positive staphylococci were detected across all processes.

Conclusions:

• Salt-requiring organisms pose a significant microbiological challenge in Maine shrimp processing.
• Post-processing handling, particularly culling and inspection, can lead to microbial re-contamination.
• Further optimization of handling procedures and sanitation is recommended to ensure the microbiological safety of processed shrimp.