Risk Assessment And Determination With Direct Analysis In Real Time Of Dicyandiamide In Powdered Milk

Food safety is not only the basic request for protecting people’s health and improving people’s living quality, but also the demand of enhancing the competitiveness of agriculture and food industry for facilitating foreign trade. Intensified food safety concern over dicyandiamide (DCD) has prompted researcher to assess its acceptable daily intake (ADI) for protection of general population including young children. ADI is calculated by dividing a no-observed-adverse-effect level (NOAEL) by a safety factor (SF) with modifying factor (MF). Because of the unavailability of ADI value for DCD, our group presumed it in the unit of mg per kg body weight per day as 26.0 based on the conventional NOAEL scheme. We used another procedure via benchmark dose (BMD) derivation, with judicious selection of pertinent values, to obtain an ADI of 21.6. Hence, the article will be an important reference for officials in charge of supervision and administration of food safety, researchers and educators of food sciences, and personnel of food industry. Arguments in support of this lower ADI value were provided to alert the international community.Reference dose is the scientific basis of standard setting for food safety, and testing technology is strong oversight of the implementation and enforcement of safety standards and validation. Therefore, quick and high efficiency are especially important in the process of detection. The Direct Analysis in Real Time (DART) ionization source coupled with a quadnipole time-of-flight tandem mass spectrometry (Q-TOF MS/MS) system has the capability to desorb analytes directly from samples without sample cleanup or chromatographic separation. In this work, a method based on DART/Q-TOF MS/MS has been developed for rapid identification of dicyandiamide (DCD) present in milk powder. Simple sample extraction procedure employing acetonitrile-water (80:20, v/v) mixture was followed by direct, high-throughput determination of sample extracts spread on a steel mesh of the transmission module by mass spectrometry under ambient conditions. The method has been evaluated for both qualitative and quantitative analysis of DCD in milk. Variables including experimental apparatus, DART gas heater temperature, sample presentation speed and vacuum pressure were investigated. The quantitative method was validated with respect to linearity, sensitivity, repeatability, precision and accuracy by using external standards. After optimization of these parameters, a limit of detection (LOD) of 100 μg kg"1 was acquired for DCD with a linear working range from 100 to 10000 μg kg"1 and a satisfactory correlation coefficient (R2) of 0.9997. Good recovery (80.08-106.47%) and repeatability (RSD=3.0-5.4%) were obtained for DCD. The DART/Q-TOF MS/MS-based method provides a rapid, efficient and powerful scheme to analyze DCD in milk powder with limited sample preparation thus reducing time and complexity of quality control.