Effect Of Microorganism Contamination On Quality And Food Security For Wheat Flour

Effect of microorganism contamination on quality and food security for wheat flour and the relationship among condition of temperature and humidity , microbe quality of wheat flour, remainder content of microtoxin and quality of wheat flour were studied in this paper , providing the foundation for storage security of wheat flour or microorganism limitation in wheat flour. It can be concluded by the results that:(1) The relationship between moisture content of wheat flour in storage(0～90d)and temperature or humidity was negative correlation and positive correlation ,respectively,and the quantity of microorganism (E.coli, Bacillus.spp, aerobic bacterial count or molds and yeasts) in wheat flour was correlated positively with moisture content (P<0.05).(2) The quantity of microorganism in wheat flour was correlated with condition of temperature and humidity significantly:The relationship of temperature and microbe quality (E.coli, aerobic bacterial count or molds and yeasts) was negative correlation respectively (P<0.05), but it was positive correlation for humidity and microbe quality (E.coli, Bacillus.spp, aerobic bacterial count or molds and yeasts).(3) The quality of wheat flour was correlated with condition of temperature and humidity significantly(P<0.05):The fatty acid vale and strength (W)were correlated positively with temperature,but it was negative correlation between precipitation number and temperature;The content of total starch or wet gluten in wheat flour,precipitation number and expansivity(L)were correlated negatively with humidity,but it was positive correlation for tenacity (P).( 4 ) Relatively, the impact of condition of temperature and humidity on quantity of protein of wheat flour was less than on protein quality in storage, which was same as between protein of wheat flour and carbohydrate or fat.( 5 ) The production of Bacillus cereus enterotoxin(BDE) or heat-stable E. coli enterotoxin (ST) was not influenced by the variation of temperature or humidity (15℃～35℃or 30%～85%),and the remainder of BDE or ST in wheat flour was not detected in storage. ( 6 ) The quantity of microorganism in wheat flour was correlated with quality of wheat flour significantly (P<0.05): Aerobic bacterial count or molds and yeasts were correlated negatively with fatty acid value,content of total starch or wet gluten,precipitation number and expansivity(L) respectively,but it was positive correlation for tenacity (P).( 7 ) When the temperature or humidity was lower than 25℃or 65%, a low moisture content (<14%) and quantity or activity of microorganism was caused to prolong the guarantee period for wheat flour and cut down remainder content of microtoxin (Aflatoxin or Ochratoxin A)in wheat flour which was safety for food.(8) The proposed acceptable microbiological quantity(Bacillus cereus﹑E.coli﹑Bacillus.spp, aerobic bacterial count or molds and yeasts)should be lower than 103cfu/g﹑103cfu/g﹑103cfu/g,104cfu/g and 103cfu/g respectively in storage to secure the food or quality security for wheat flour.The results show that the condition of temperature and humidity in storage was correlated with microbe activity or quality of wheat flour. When the condition of storage was disgusting, physiological activity of microorganism was strengthened, which resulted a short guarantee period for wheat flour and made threatens for food security. Therefore, the impact of interaction between temperature and humidity on microbe activity or quality of wheat flour in storage should be considered in storage to keep a right temperature or humidity for the quality or food security of wheat flour.