Comparing Different Packaging Conditions on Quality Stability of High-Pressure Treated Serra da Estrela Cheeses during Cold Storage

Serra da Estrela cheese with a Protected Designation of Origin (PDO) is a traditional cheese that is wrapped in paper without vacuum. High-pressure processing (HPP), which requires vacuum packaging of the cheese, has been used for its cold pasteurization to overcome safety issues. In this study, two packaging systems were studied: non-vacuum greaseproof paper wrapping package and vacuum packaging in plastic film. Lactococci, lactobacilli, enterococci, and total mesophiles reached ca. 8 log cfu g(-1) and 4-6 log cfu g(-1) in control (unpasteurized) and HPP-treated cheeses, respectively, with no significant differences between packaging systems. Spoilage microorganisms' viable cell numbers were reduced to <3 log cfu g(-1) (quantification limit) in HPP-treated cheeses, independently of the packaging system. Yeasts and molds reached >5 log cfu g(-1) in non-vacuum paper-wrapped cheeses. A vacuum-packaging system enabled better control of cheese proteolysis, which was revealed to be closer to that of the original control cheese values at the end of the 10-month storage period. In addition, cheese stored under vacuum film packaging became harder than non-vacuum paper-wrapped cheeses at each time point. Overall, conventional non-vacuum paper wrapping is adequate for short storage periods (<3 months), but for long periods vacuum packaging in plastic film is preferable.

Automated summary

This study compared the effects of non-vacuum greaseproof paper wrapping and vacuum packaging in plastic film on Serra da Estrela cheese. The results showed that there were no significant differences in the counts of lactococci, lactobacilli, enterococci, and total mesophiles between the two packaging systems. Yeasts and molds were present in higher numbers in non-vacuum paper-wrapped cheeses. Vacuum packaging allowed for better control of cheese proteolysis and resulted in a harder texture compared to non-vacuum paper-wrapped cheeses. Overall, non-vacuum paper wrapping is suitable for short-term storage, while vacuum packaging in plastic film is preferable for long-term storage.