Efeito da aplicação de ultrassom sobre a inibição de Listeria monocytogenes e qualidade de mortadelas

Abstract

The growing demand for ready-to-eat (RTE) foods raises concerns about the safety of these products, primarily due to the risk of Listeria monocytogenes contamination. Its ability to develop under adverse conditions, in addition to the potential formation of biofilms, makes its control difficult. Sodium nitrite, used as a preservative in meat products, has antimicrobial action against Listeria, but its use is questioned due to the risk of forming carcinogenic compounds. An alternative is the use of ultrasound, a non-thermal technology that has shown promise in the food industry for inactivating microorganisms and enzymes without affecting the nutritional and sensory quality of food. Therefore, the objective of this study was to evaluate the effect of ultrasound on the lethality of Listeria monocytogenes in sliced mortadella and to determine whether reducing nitrite use, combined with ultrasound, maintains mortadella quality during refrigerated storage. In the first experiment, a DCCR was performed to evaluate the effect of ultrasound time and power on the lethality of L. monocytogenes and the quality of mortadella. Listeria growth in cell suspension was affected (P<0,05) by sonication time, while power provided the highest inactivation rates (P<0,05) in mortadella. Overall, differences (P<0,05) were observed only in the weight loss attributes for syneresis and freezing cycle, fracture energy, Eh, and aw. However, ultrasound application at 477 W for 11,8 minutes provided the greatest inactivation (a reduction of 6.22 logarithmic cycles) with minor changes in these attributes. Subsequently, a second factorial experiment was carried out in DIC to evaluate the effect of the treatment, composed of nitrite content (0,50, 100 and 150 mg/kg) and the application of ultrasound (400W; 10 min), and of the storage time on the quality of the mortadella. The treatment affected (P<0,05) only the residual nitrite and heme pigment content, and the hue index (h), mainly due to the nitrite content. Therefore, the minimal effects observed by the application of ultrasound characterize it as a promising strategy for application in meat products, especially with regard to pathogen control and additive reduction.