AOAC 2019 First Action Methods

Table 2019.01A. Summary of results for detection of Cronobacter in reconstituted powdered infant formula with probiotics by GENE-UP ® Cronobacter Inoculation level Noninoculated a Low a High a Candidate presumptive positive/total No. of samples analyzed 1/120 91/120 120/120 Candidate presumptive LPOD 0.01 (0.00, 0.05) 0.75 (0.68, 0.84) 1.00 (0.97, 1.00) s r b 0.09 (0.08, 0.17) 0.43 (0.38, 0.50) 0.00 (0.00, 0.17) s L c 0.00 (0.00, 0.04) 0.01 (0.00, 0.19) 0.00 (0.00, 0.17) s R d 0.09 (0.08, 0.11) 0.43 (0.38, 0.50) 0.00 (0.00, 0.24) P value e 0.4410 0.4292 1.0000 Candidate confirmed positive/total No. of samples analyzed 0/120 91/120 120/120 Candidate confirmed LPOD 0.00 (0.00, 0.03) 0.75 (0.68, 0.84) 1.00 (0.97, 1.00) s r 0.00 (0.00, 0.17) 0.43 (0.38, 0.50) 0.00 (0.00, 0.17) s L 0.00 (0.00, 0.17) 0.01 (0.00, 0.19) 0.00 (0.00, 0.17) s R 0.00 (0.00, 0.24) 0.43 (0.38, 0.50) 0.00 (0.00, 0.24) P value 1.0000 0.4292 1.0000 Candidate presumptive positive that confirmed positive/total No. of samples analyzed 0/120 91/120 120/120 Candidate presumptive positive that confirmed LPOD 0.00 (0.00, 0.03) 0.75 (0.68, 0.84) 1.00 (0.97, 1.00) s r 0.00 (0.00, 0.17) 0.43 (0.38, 0.50) 0.00 (0.00, 0.17) s L 0.00 (0.00, 0.17) 0.01 (0.00, 0.19) 0.00 (0.00, 0.17) s R 0.00 (0.00, 0.24) 0.43 (0.38, 0.50) 0.00 (0.00, 0.24) P value 1.0000 0.4292 1.0000 Positive reference samples/total No. of samples analyzed 0/120 101/120 120/120 Reference LPOD 0.00 (0.00, 0.03) 0.84 (0.77, 0.91) 1.00 (0.97, 1.00) s r 0.00 (0.00, 0.17) 0.38 (0.33, 0.44) 0.00 (0.00, 0.17) s L 0.00 (0.00, 0.17) 0.00 (0.00, 0.13) 0.00 (0.00, 0.17) s R 0.00 (0.00, 0.24) 0.38 (0.34, 0.43) 0.00 (0.00, 0.24) P value 1.0000 0.8686 1.0000 dLPOD (candidate versus reference) f 0.00 (–0.03, 0.03) –0.08 (–0.19, 0.02) 0.00 (–0.03, 0.03) dLPOD (candidate presumptive versus candidate confirmed) f 0.01 (–0.02, 0.05) 0.00 (–0.11, 0.11) 0.00 (–0.03, 0.03) a  Results include 95% confidence intervals. b  s r =Repeatability SD. c  s L =Among-laboratory SD. d  s R =Reproducibility SD. e P value=Homogeneity test of laboratory PODs. f  A confidence interval for dLPOD that does not contain the value 0 indicates a statistically significant difference between the two methods.

( q )  Chromogenic Cronobacter isolation (CCI) agar .―Stock No. 421580. ( r )  Cronobacter Selective Broth (CSB) .―Stock No. 421569.

C. General Instructions ( a ) The GENE-UP Cronobacter kit is for professional use only with the GENE-UP Lysis Kit. ( b ) Comply with good laboratory practices. ( c ) Do not use reagents after the expiration date indicated on the label. ( d ) Visually inspect vials before testing. Do not use vials with evidence of damage, leakage, or deterioration. ( e ) Do not mix reagents (or disposables) from different lots. ( f ) Powder-free latex or nitrile gloves are recommended for all PCR steps. ( g ) The equipment and accessories should be regularly cleaned and decontaminated. ( h ) Never remove the caps from the lysis tubes. ( i ) Do not try to remove the strip tube caps once they have been sealed to the PCR strip tubes.

( s )  API ID32E .―Stock No. 20160. ( t )  Fast Crono .―Stock No. 417425.

Additional items: ( u )  Incubators .―Capable of maintaining 37±1°C. ( v )  Adjustable variable-volume pipets .―Capable of sampling and delivering 10–20 µL. ( w )  Adjustable variable-volume pipets (single or multichannel) .―Capable of sampling and delivering 0.5–10 µL. ( x )  Compatible sterile filter pipet tips .―20 µL. ( y )  Refrigerator .―Capable of maintaining 2–8°C. ( z )  Vortex-Genie Pulse .―Stock No. SI-P236 (Scientific Industries, Inc., Bohemia, NY, USA).

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