Comparison of Impedance, Microbial, Sensory, and pH Methods to Determine Shrimp Quality

This study compared the relative ability of several techniques to measure shrimp quality. Fresh raw white shrimp (Penaeus setiferis) were stored whole at −20, 5, 25, and 35°C, sampled periodically, and measured for sensory odor score, psychro-trophic microbial numbers, pH, and Bactometer impedance values. Impedance, odor, and microbial numbers were highly correlated and predictive of quality, while pH was not an appropriate gauge of quality. Correlation of impedance with odor was 0.89, with a Bactometer I-value of 2175 or greater indicative of spoiled shrimp. This study provides continuing evidence that an impedimetric method can be used as a rapid, easy, and objective tool to measure shrimp quality.