Evaluation and suitability of biomaterials for modified atmosphere packaging of fresh salmon fillets

An evaluation of the suitability of commercially available biopolymers on the shelf‐life of fresh salmon fillet was done. The comparison included two different types of biomaterials, poly lactic acid (PLA)‐based and starch‐based materials, and two traditional materials, amorphous polyethylene terephthalate/polyethylene (APET/PE) and high‐density polyethylene (HDPE). Fresh salmon fillets were stored at 4°C in modified atmosphere (60% CO₂ and 40% N₂) for 5, 7, 9 and 14 days. The biomaterials have been briefly evaluated with respect to composition and mechanical properties. The effect of different packaging materials on bacterial growth, off‐odour, pH and colour was investigated. The traditional materials (APET/PE and HDPE trays) offered the best protection regarding the bacterial growth. A relatively high level (log 6 CFU/g) of total viable counts was detected after 9 days and 14 days for fillets stored in biomaterials and traditional materials, respectively. The level of lactic acid bacteria and H₂S producing bacteria followed almost the same pattern. Storage in traditional materials resulted in higher intensity of freshness (fresh odour) compared with the samples stored in biomaterials; after 14 days, the salmon stored in starch‐based pouches was regarded as having lower intensity of freshness compared with APET/PE trays and PLA‐based pouches. The opposite result was obtained regarding the colour of the salmon, where the biomaterials resulted in higher intensity of fresh colour compared with the traditional materials although the surface of the salmon at the end of the experiment was dry and unpleasant. Copyright © 2011 John Wiley & Sons, Ltd.