RESULTS: Compared with the neat semolina film, mechanical strength (TS) of the nanocomposite films increased significantly (increase in 21-65%) and water vapor barrier (WVP) and O2 gas barrier (OP) properties decreased significantly (decrease in 43-50% and 60-65%, respectively) depending on the blending ratio of ZnO and kaolin nanoclay. The nanocomposite films also exhibited strong antimicrobial activity against bacteria (E. coli and S. aureus), yeast (C. albicans), and mold (A. niger). The nanocomposite packaging films were effectively prevented the growth of microorganisms (coliforms, total microbial, and fungi) of the cheese during storage at low-temperature and showed microbial growth of less than 2.5 log CFU/g after 72 days of storage compared to the control group, and the quality of the packaged cheese was still acceptable.
CONCLUSION: The semolina-based nanocomposite films, especially Sem/Z3 K2 film, were effective for packaging of low moisture mozzarella cheese to maintain the physicochemical properties (pH, moisture, and fat content) and quality (color, taste, texture, and overall acceptability) of the cheese as well as preventing microbial growth (coliforms, total microbial, and fungi). © 2018 Society of Chemical Industry.
METHODS: The Prospective Urban Rural Epidemiology (PURE) study is a large multinational cohort study of individuals aged 35-70 years enrolled from 21 countries in five continents. Dietary intakes of dairy products for 136 384 individuals were recorded using country-specific validated food frequency questionnaires. Dairy products comprised milk, yoghurt, and cheese. We further grouped these foods into whole-fat and low-fat dairy. The primary outcome was the composite of mortality or major cardiovascular events (defined as death from cardiovascular causes, non-fatal myocardial infarction, stroke, or heart failure). Hazard ratios (HRs) were calculated using multivariable Cox frailty models with random intercepts to account for clustering of participants by centre.
FINDINGS: Between Jan 1, 2003, and July 14, 2018, we recorded 10 567 composite events (deaths [n=6796] or major cardiovascular events [n=5855]) during the 9·1 years of follow-up. Higher intake of total dairy (>2 servings per day compared with no intake) was associated with a lower risk of the composite outcome (HR 0·84, 95% CI 0·75-0·94; ptrend=0·0004), total mortality (0·83, 0·72-0·96; ptrend=0·0052), non-cardiovascular mortality (0·86, 0·72-1·02; ptrend=0·046), cardiovascular mortality (0·77, 0·58-1·01; ptrend=0·029), major cardiovascular disease (0·78, 0·67-0·90; ptrend=0·0001), and stroke (0·66, 0·53-0·82; ptrend=0·0003). No significant association with myocardial infarction was observed (HR 0·89, 95% CI 0·71-1·11; ptrend=0·163). Higher intake (>1 serving vs no intake) of milk (HR 0·90, 95% CI 0·82-0·99; ptrend=0·0529) and yogurt (0·86, 0·75-0·99; ptrend=0·0051) was associated with lower risk of the composite outcome, whereas cheese intake was not significantly associated with the composite outcome (0·88, 0·76-1·02; ptrend=0·1399). Butter intake was low and was not significantly associated with clinical outcomes (HR 1·09, 95% CI 0·90-1·33; ptrend=0·4113).
INTERPRETATION: Dairy consumption was associated with lower risk of mortality and major cardiovascular disease events in a diverse multinational cohort.
FUNDING: Full funding sources are listed at the end of the paper (see Acknowledgments).