Application of Iron Oxide as a pH-dependent Indicator for Improving the Nutritional Quality

Acid food indicators can be used as pH indicators for evaluating the quality and freshness of fermented products during the full course of distribution. Iron oxide particles are hardly suspended in water, but partially or completely agglomerated. The agglomeration degree of the iron oxide particles depends on the pH. The pH-dependent particle agglomeration or dispersion can be useful for monitoring the acidity of food. The zeta potential of iron oxide showed a decreasing trend as the pH increased from 2 to 8, while the point of zero charge (PZC) was observed around at pH 6.0-7.0. These results suggested that the size of the iron oxide particles was affected by the change in pH levels. As a result, the particle sizes of iron oxide were smaller at lower pH than at neutral pH. In addition, agglomeration of the iron oxide particles increased as the pH increased from 2 to 7. In the time-dependent aggregation test, the average particle size was 730.4 nm and 1,340.3 nm at pH 2 and 7, respectively. These properties of iron oxide particles can be used to develop an ideal acid indicator for food pH and to monitor food quality, besides a colorant or nutrient for nutrition enhancement and sensory promotion in food industry.

Epidemiological characteristics and influencing factors of hand-foot-mouth disease outbreaks in kindergartens / 中国感染控制杂志

Objective To study the epidemiological characteristics and influencing factors of hand-foot-mouth dis-ease(HFMD)outbreaks in kindergartens,so as to provide reference for control and prevention of HFMD. Methods Papers published between 2009 and 2015 about HFMD outbreaks in kindergartens were retrieved from Wanfang database and China National Knowledge Infrastructure (CNKI),then collected papers were analyzed. Results Data about 39 cases of HFMD outbreaks were obtained,35 cases occurred in 2008-2012,1 case occurred respectively in 2007,2013,2014,and 2015. 33.34% and 23.08% of outbreaks occurred in May and April. Out-breaks lasted 5-52 days,with a median of 11 days,30.77% of outbreaks lasted more than 2 weeks. The attack rates of the whole kindergartens were 1.90% -39.74% ,attack rates of whole kindergartens were 5% -15% a-mong 65.79% of outbreaks,attack rate of whole kindergartens was >20% among 13.16% of outbreaks. 85.71%of outbreaks involved more than 20% of classes,25.71% of which involved all classes. Both EV71 and CoxA16 caused HFMD outbreaks in kindergartens,two kinds of viruses were both detected in some outbreaks;there were no significant difference in attack rate of whole kindergartens,attack rate of classes with highest incidence,class in-volving rate,and duration of epidemic between EV71 and CoxA16 epidemic groups(all P>0.05).Conclusion Once an HFMD outbreak occurred in a kindergarten,epidemic intensity would be high,both EV71 and CoxA16 can cause HFMD outbreak. There is no obvious correlation between class size and attack rate.