, 2010 and Lemay et al., 2002. These results may be explained by the rich nutritional contents that are favorable for growth PI3K inhibitor of target microorganism and temperature of samples storage (25 °C). According to Labbé (2000), C. perfringens grows at temperatures between 15 and 50 °C; in addition the spores

germination, favored by elevated storage temperature, may lead to a population growth. A possible alternative to control the C. perfringens population growth during the shelf-life of the product is the use of combined preservation methods called the “hurdle technology”. This technology combines low temperatures, radiation, modified atmosphere packages (MAP) and vacuum packaging (VP), high-pressure techniques and heat processing

among others, always aiming to maintain the natural sensory properties of food ( Tsigarida et al., 2000, Tassou et al., 1995 and Ouattara et al., 2001). At the end of the storage period (day 30) a pronounced decrease of viable cell counts in all of the treatments was observed, which may have been a result of a decrease in pH (data not shown) in the mortadella samples at the end of the storage period. According to Scott et al. (2001), C. SNS-032 in vitro perfringens is a spoilage saccharolytic bacterium that ferments carbohydrates, generating final products including butyric and acetic acids, which are able to reduce pH medium. Mortadella has a considerable amount of fermentable carbohydrates (starch), which were metabolized by a large numbers of C. perfringens cells inoculated in the food model, resulting in acid production and thereby decreasing the pH. In addition,

the possible growth of thermotolerant microbial companion, remnants after the cooking process, which are naturally present in meat and meat products, produces antibacterial factors such as bacteriocins, antimicrobial peptides, ethanol, peroxide Bay 11-7085 and organic acids leading to a reduction in C. perfringens counts. High levels of indigenous, nonpathogenic microorganisms may have a protective effect on meat and meat products by out-competing pathogens. The spore counts increased at the end of the storage period. According to Mitchell (2001), the sporulation is initiated in response to a lack of nutrients, and is affected by pH, oxygen tension and temperature. In general sporulation process is favored by conditions that result in a reduced growth rate. In conclusion, the synergistic effect between EO and NaNO2 on C. perfringens type A inoculated in mortadella-type sausages was observed. The results suggest the combined use of EO and reduced amounts of NaNO2 to control C. perfringens, going according current market trends, for natural products. However, EOs alone cannot provide complete protection against C. perfringens in mortadella.