T/AFFI 039-2023 Active

Main Technical Content: 1. Scope: This standard applies to the determination of Aspergillus niger in grapes. It specifies the testing method for Aspergillus niger in grapes. This document is applicable to the detection of Aspergillus niger in fresh grapes and raisins in Xinjiang region. 2. Normative References: The referenced documents in this document are essential for its application. For dated referenced documents, only the version on the specified date is applicable to this document. For undated referenced documents, the latest version (including all amendments) is applicable. GB/T 6682 – Specification for Class I Water Used in Analytical Laboratories 3. Terms and Definitions 3.1 Fresh Grapes: Fresh, clean grapes that have undergone certain processing or preservation treatments. 3.2 Raisins: Grapes that have been dehydrated by natural drying or artificial heating methods. 3.3 Aspergillus niger: A common species of fungus in the subclass of Hypocreomycotina, order Mucorales, family Aspergillaceae. It thrives and multiplies rapidly in high-temperature and high-humidity environments and is often found on juicy fruits, causing rotting and spoilage. 4. Principle: Aspergillus niger in infected grapes can be cultured on potato-glucose agar at 28°C for 5 days to detect the mold, isolate Aspergillus niger, identify it through biochemical testing, and count the number of Aspergillus niger per milliliter of sample. 5. Culture Media and Reagents 5.1 Culture Media 5.1.1 Potato-glucose agar (PDA) 5.1.2 2% starch Czapek's agar 5.2 Reagents 5.2.1 Sterile physiological saline solution 5.2.2 I2-Ki reagent (Pollen viability staining solution) 6. Standard Strains 6.1 Aspergillus niger standard strains 7. Instruments and Equipment 7.1 Incubator: 28°C ± 1°C 7.2 Peristaltic homogenizer and homogenization bags 7.3 Sterile conical flasks: 500 mL capacity 7.4 Sterile pipettes: 1 mL (with 0.01 mL graduations), 10 mL (with 0.1 mL graduations) 7