采用压电体声波传感器实时快速检测米粉中的菌落总数。该传感器包括压电石英晶体、检测池、振荡器、频率计和显示器,其检测原理是基于压电体声波传感器对微生物存在的培养体系的电参数变化有灵敏的频移响应,而自制软件能以频移-时间的形式将此变化过程实时记录下来。本研究中将频移显著变化的点所对应的时间定义为微生物检出时间(MDT),将基于MDT检出微生物的方法称为频移检测法。将不同污染程度的米粉样品用频移检测法获得的MDT与平板计数法获得的初始菌落数建立标定方程。当微生物初始菌落数在103～108cfu/g之间时获得标定方程logC=7.7923-0.0071MDT(r=0.985)。通过标定方程得到的不合格样品(参照国家和地方标准)的测定时间仅需7.8h,远小于国标方法的48h。利用建立的压电传感法检测13个米粉样品的菌落总数,并与平板计数法比较,结果表明,压电体声波传感器法具有准确、快速、操作简便等特点,有望在米粉制品的菌落总数检测中得到推广应用。 Piezoelectric acoustic sensor real-time rapid detection of the total number of colonies in rice noodles. The sensor includes piezoelectric quartz crystal, detection cell, oscillator, frequency meter and display. The detection principle is based on the sensitive frequency shift response of the piezoelectric acoustic transducer to the variation of the electrical parameters of the culture system in which microorganisms exist. Record this change in real time in the form of frequency shift-time. In the present study, the time corresponding to a significant change in frequency shift was defined as the time to detect microorganisms (MDT), and the method for detecting microorganisms based on MDT was referred to as frequency shift detection. The rice samples with different pollution levels were calibrated using MDT obtained by the frequency shift assay and the initial number of colonies obtained by the plate counting method. The calibration equation logC = 7.7923-0.0071 MDT (r = 0.985) was obtained when the initial number of microorganisms was between 103 and 108 cfu / g. The measurement time of unqualified samples (refer to national and local standards) obtained through the calibration equation is only 7.8h which is much smaller than the 48h of the national standard method. The total number of colonies of 13 rice samples was measured by the established piezoelectric sensing method and compared with the plate counting method. The results showed that the piezoelectric acoustic sensor method was accurate, rapid and easy to operate. It is expected that the total number of colonies Detection has been widely used.