A rapid method for detecting pathogenic Cronobacter turicensis in infant formula milk powder was developed by combining multienzyme isothermal rapid amplification (MIRA) with the CRISPR/Cas12a system. Based on the CTU_22970 gene sequence of C. turicensis, specific MIRA primers and CRISPR RNA (CrRNA) sequences were designed. The target DNA of C. turicensis was amplified using the highly efficient and sensitive MIRA method. The presence of the target DNA activated the trans-cleaving activity of the CrRNA-Cas12a complex. The detection signal was then read using colloidal gold-based lateral flow immunochromatography. The detection system developed in this study had good specificity and sensitivity. The presence of other species of Cronobacter and non-Cronobacter strains were verified to not activate the trans-cleavage activity of Cas12a. Detection was completed within 1.5 h, and the detection limit for C. turicensis (for pure cultures) was 1 CFU/mL. For actual samples, milk powder with an initial bacterial count of 105 CFU/g can be detected without enrichment, while samples with initial bacterial counts of 104, 103, 102, 101, and 100 CFU/g need pre-incubation for 2, 4, 6, 8, and 10 h, respectively, for successful detection of C. turicensis. The detection process is simple and requires no large devices or equipment and professional training. It is suitable for on-site detection and of significant practical importance for controlling and monitoring C. turicensis in food.