A Method to Directly Identify Cronobacter sakazakii in Liquid Medium by MALDI-TOF MS

• Published in: Foods Vol. 12; no. 10; p. 1981
• Main Authors: Song, Danliangmin, Su, Qunchao, Jia, Ai, Fu, Shiqian, Ma, Xiaoming, Li, Tiantian, Man, Chaoxin, Yang, Xinyan, Jiang, Yujun
• Format: Journal Article
• Language: English
• Published: Switzerland MDPI AG 12.05.2023; MDPI
• Subjects: Accuracy; Acetonitrile; Baby foods; Bacteria; Cronobacter sakazakii; direct identification; Food science; Foodborne pathogens; Formic acid; Identification; Infants; Ionization; Ions; Lasers; Lethality; liquid spotting; MALDI-TOF MS; Mass spectrometry; Mass spectroscopy; Methods; Microorganisms; New technology; Optimization; Parameters; Pathogens; Response surface methodology; Ultrasonic imaging; Beijing China; China; MALDI-TOF MS; liquid spotting; response surface methodology; Cronobacter sakazakii; direct identification
• ISSN: 2304-8158; 2304-8158
• DOI: 10.3390/foods12101981

Matrix-assisted laser desorption ionization time-of-flight mass spectrometry has been widely used as an emerging technology for the rapid identification of microorganisms. is a food-borne pathogen of particular importance to the powdered infant formula (PIF) processing environment due to its high lethality in infants. However, the traditional solid spotting detection method of pretreating samples for MALDI-TOF MS leads only to qualitative detection of . We developed a new, low-cost, robust liquid spotting pretreatment method and used a response surface methodology to optimize its parameters. The applicability, accuracy, and quantitative potential were measured for different types of samples. The optimal parameters of this method were as follows: a volume of 70% formic acid of 25 μL, treatment with ultrasound at 350 W for 3 min, and a volume of acetonitrile added of 75 μL. These conditions led to the highest identification score for (1926.42 ± 48.497). This method was found to detect bacteria accurately and reproducibly. When 70 strains of isolates were analyzed with this method, the identification accuracy was 100%. The detection limit of in environmental and PIF samples was 4.1 × 10 cfu/mL and 2.72 × 10 cfu/mL, respectively.