The growth of Listeria monocytogenes in fresh goat cheese (Cameros cheese) packaged under modified atmospheres Original Research Article

The effect of modified atmosphere packaging (MAP) on the growth of Listeria monocytogenes in inoculated and non-inoculated Cameros cheese was evaluated. Three different modified atmosphere conditions were studied (20%CO2/80%N2, 40%CO2/60%N2 and 100%CO2). Control cheeses were packaged in air. The product was stored at 4°C and evaluated periodically to investigate its microbiological quality. MAP presented an extended shelf-life. Those containing CO2 reduced the growth rate of mesophiles, psychrotrophs and anaerobes, which was lower when the CO2 concentration increased. A concentration of 100% CO2 showed the lowest microbial counts. L. monocytogenes growth was lower when the CO2 concentration increased. However, after 28 days the L. monocytogenes population was 1·3 log units lower in inoculated cheeses packaged at 100% CO2 than in those packaged in air. Listeria monocytogenes can grow in atmospheres containing 20, 40 and 100% CO2. L. monocytogenes were not found in any of the non-inoculated samples. It was concluded that MAP was not a suitable means to prevent the growth of L. monocytogenes in Cameros cheese.