Modeling the combined resistance to microwave treatments and salt conditions of Escherichia coli and Staphylococcus aureus.

In the present study, the efficiency of the combined effect of microwave irradiation treatments together with salt concentration was assessed against Escherichia coli and Staphylococcus aureus. Microbial survival has been modeled through a one-step Weibull equation considering the non-isothermal profiles during the heating treatments. Three sodium chloride concentrations 0.5%, 3.5%, and 8.5% (w/v) treated under three microwave power levels (450, 600, and 800 W) were studied. Predictive models were validated using the determination coefficient (R2), root mean squared error and the acceptable prediction zone with external data obtained from ultra high temperature milk. The results obtained suggested that increasing microwave power levels and decreasing salt concentrations led to a higher microbial inactivation, being the δ values (time for achieving a first decimal reduction) for E coli of 19.57 s at 800 W and 0.5% NaCl. In contrast, experimental data of S aureus showed a higher variability since it presented more resistance to the microwave treatments. The results obtained and generated models can be used as decision-making tools to set specific guidelines on microwave treatments for assuring food safety.

Comparative mapping approach of energy intake and expenditure of obesity prevalence among school adolescents.

OBJECTIVE: This study aims to describe the prevalence of overweight and obesity in an obesogenic environment among adolescents in the wilaya of Bejaia (eastern Algeria), and to assess their Physical Activity Level (PAL), Daily Energy Expenditure (DEE) and Total Energy Intake (TEI). METHODS: A cross-sectional study was carried out on a sample of 3038 adolescents consisting of 1635 girls and 1403 boys in middle and high schools in 19 regions of Bejaia. The average age was 14.78 ± 2.53. Two questionnaires were assigned to collect data on their nutritional habits (24-h dietary call) and physical activity levels. BMI measurement was adopted in this study to determine the weight status of this sample and to assess the distribution of BMI, PAL, DEE, TEI over geographical areas of an administrative territory using the Student test descriptive statistical method (p < 0.05). RESULTS: The prevalence of obesity and overweight was equal to 3.3%, the physical activity level in adolescents was 1.72 ± 0.21, with boys more likely to participate in sports than girls (16.5% for boys and 6% for girls). However, energy intake (3775.44 ± 719.07 kcal/day), energy expenditure (3144.13 ± 850.54 kcal) and body mass index (30.51 ± 2.99 kg/m2) were high. Body mass index (BMI) is negatively correlated with PAL (r = -0.05) and positively correlated with TEI (r = 0.31) and DEE (r = 0.30), these results show that DEE and TEI factors play an important role in the prevalence of BMI with excessive consumption of high carbohydrate (614.55 g) and fat (98.9 g) foods, which is due to poor diet and are related to insufficient level of physical activity. The mapping shows that there is a disparity between the studied parameters: high BMI, low PAL and consumption of unhealthy foods (DEE, TEI). CONCLUSION: The lack of physical activity and the imbalance between energy intake and expenditure are the main factors that could lead to an increased risk of obesity in adolescents.