RESUMO
The presence of Listeria monocytogenes in Mozzarella di Bufala Campana Protected Designation of Origin cheeses may depend on curd stretching conditions and post contaminations before packaging. To avoid cross-contamination, thermal treatment of water, brines and covering liquid may become necessary. The present study aimed to improve knowledge about L. monocytogenes thermal resistance focusing on the influence of some cheese making operations, namely curd stretching and heat treatment of fluids in contact with cheese after molding, in order to improve the safety of the cheese, optimize efficacy and sustainability of the processes. Moreover, the role that cheese curd stretching plays in L. monocytogenes inactivation was discussed. The 12 tested strains showed a very heterogeneous heat resistance that ranged from 7 to less than 1 Log10 Cfu/mL reduction after 8 min at 60°C. D-values (decimal reduction times) and z-values (thermal resistance constant) calculated for the most heat resistant strain among 60 and 70°C were highly affected by the matrix and, in particular, heat resistance noticeably increased in drained cheese curd. As cheese curd stretching is not an isothermal process, to simulate the overall lethal effect of an industrial process a secondary model was built. The lethal effect of the process was estimated around 4 Log10 reductions. The data provided may be useful for fresh pasta filata cheese producers in determining appropriate processing durations and temperatures for producing safe cheeses.
RESUMO
OBJECTIVE: The relationship between whole blood fatty acids and myocardial infarction (MI) risk has not been analyzed in detail, especially in Mediterranean countries. The AGE-IM (Acidi Grassi Essenziali e Infarto Miocardico) study was planned to examine the relationships between MI, whole blood fatty acids and the diet in an Italian cohort. METHODS: 119 Patients with a recent MI and 103 control subjects were enrolled in the study. The whole blood fatty acid composition was determined; information on anthropometrics, biochemical parameters and blood pressure values were also obtained. Diet composition was assessed using a validated food frequency questionnaire from 86 cases and 72 controls. RESULTS: Total PUFA, omega-6 and omega-3 PUFA (as percentage of whole blood fatty acids) were significantly lower in MI patients than in matched controls, whereas saturated and monounsaturated fatty acids were higher in cases. MI infarction risk significantly and steadily decreased with increasing levels of total PUFA (OR: 0.14) and of total omega-6 and omega-3 (OR: 0.15 and 0.37, respectively). No correlation was identified between dietary fats and MI risk or between whole blood fatty acid levels and dietary nutrients and fats. CONCLUSION: Percentage levels of total PUFA, total omega-3 PUFA and total omega-6 PUFA are lower in MI patients than in matched control subjects in the AGE-IM cohort. These data support a favorable association not only of whole blood percentage levels of total omega-3, but also of total omega-6, with cardiovascular risk.
