Effectiveness of CO2and Nisaplin on increasing shelf-life of fresh pizza Original Research Article

Acidification and CO2release resulting from fermentative metabolism of lactic acid bacteria and yeasts were the principal grounds for rejection of ham pizza stored under 20% CO2(commercial conditions). Ham and tomato paste were identified as major sources of fermentation. A rotatable factorial design with the aim of studying the effects of Nisaplin and modified atmosphere packaging (MAP) showed that CO2reduced gas release and had little effect on acidification. In contrast, Nisaplin did not have a significant positive effect on gas release, although it minimized acidification at high CO2concentrations. The combined use of Nisaplin and MAP lead to significant increases in shelf-life in relation to commercially stored samples, and were ascribed to complementary effects of nisin and CO2against lactic acid bacteria and yeasts, respectively. Subsequent studies aiming to optimize the addition of Nisaplin showed that optimum effectiveness in spoilage prevention could be achieved by using highly CO2-enriched atmospheres in conjunction with 100 mg kg−1of Nisaplin added to the top of the pizza and mixed in the tomato paste.