Microbiological Quality of Desalted Cod in Consumer Packages—Effects of Storage Atmospheres and Pretreatments

Abstract

The effect of modified atmosphere (MA) packaging using CO2 (50%) combined with different balancing gases (N2 and O2, 50%) was investigated and compared to packaging in air. In addition, the suitability of phosphate brining and steaming as a pretreatment of desalted cod to increase product quality was investigated. Headspace gas composition (%), drip loss (%), pH, and microbial counts were assessed in the desalted and packaged portions. Storage in MA significantly (p < .001) decreased the aerobic plate counts (APC), psychrotrophic counts (PC), and yeast counts by 2–3 log10 units after 15 days of chilled storage (2–3°C) as compared to storage in air. Using O2 or N2 as balancing gas had no significant impact on the microbiological counts. Application of N2 as a balancing gas significantly (p < .050) increased the drip loss as compared to balancing with O2 or storage in air. Pretreatment with phosphate brine significantly increased the weight of the portions as compared to steam treated and control groups. Phosphate-treated products had significantly (p < .001) decreased CO2 and increased O2 in the packaging headspace and a significantly (p < .001) higher pH (0.12–0.16 pH units) compared to the other treatment groups. No significant effects of pretreatments on the microbiological characteristics were observed. The use of MA for packaging of desalted cod portions increases the microbiological quality of the products.