The study, authored by Yu Cao, Robyn Dorothy Warner and Zhongxiang Fang and published in international journal, Food Control, aimed to investigate a combination of nisin/gallic acid/chitosan coating and high-oxygen modified atmosphere packaging (HO MAP, 80 percent O₂ and 20 percent CO₂) on the preservation of fresh pork loin during cold storage (2 ± 1 °C, 20 days).

A variety of nisin, gallic acid and chitosan combinations were trialled on pork loins for their effects on preserving pH, texture and colour; effects on lipid oxidation and protein oxidation; and on minimising bacterial growth.

The results of the study showed that a combination of all three – nisin, gallic acid and chitosan – and HO MAP provided the most effective preservation for samples stored at 2 ± 1 °C. This combination was able to slow the increase in lightness of pork samples, maintain redness and tenderness, reduce lipid and protein oxidation, and inhibit microorganism growth.

Application of chitosan coating to HO MAP pork loins had antimicrobial and antioxidant activities during cold storage. The addition of nisin alone improved the antimicrobial activity and the addition of gallic acid enhanced both antioxidant and antimicrobial properties.

The authors have suggested that this combination technique could be used as a cost-effective hurdle packaging technology in the preservation of fresh pork.