AOAC 2017 First Action Methods

Table 2017.09E. Summary of results for the identification of Cronobacter: Inclusivity

Correctly identified

Incorrectly identified

Total

Selective media no growth

Organism

MALDI Biotyper Reference

MALDI Biotyper

Reference

MALDI Biotyper Reference

C. condimenti QL 17031.1 a C. dublinensis QL 17031.2 C. dublinensis CCUG 58094 b C. malonaticus QL 123015.1A C. malonaticus CCUG 28859 C. muytjensii ATCC 51329 c C. sakazakii CCUG 21205 C. sakazakii CCUG 28857 C. sakazakii CCUG 28867 C. sakazakii CCUG 28870 C. sakazakii FSL F6-023 d

41 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42

14 14 14 12 14 13 14 14 13 12 11 14 14 14 13 14

0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

0 0 0 2 0 1 0 0 1 2 3 0 0 0 1 0

1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0

41 42 42 42 42 42 42 42 42 42 42 42 42 42 42 42

14 14 14 14 14 14 14 14 14 14 14 14 14 14 14 14

C. sakazakii FSL F6-032 C. sakazakii FSL F6-038 C. sakazakii FSL F6-041 C. sakazakii FSL F6-046 C. sakazakii FSL F6-051

 Total isolates

671

214

10

1 e

671 f

224 g

a  QL = Q Laboratories Collection (Cincinnati, OH, USA). b  CCUG = Culture Collection University Gothenburg (Gothenburg, Sweden). c  ATCC = American Type Culture Collection biological materials resource (Manassas, VA, USA). d  FSL = Collection of the Food Safety Laboratory, Cornell University (Ithaca, NY, USA). e  No growth on CCI only. f  Total numbers represent isolates analyzed on the three recommended culture media: TSA, CCI, and ESIA. g  Reference method performed from TSA agar only.

( i ) Internal positive E. coli DNA .—Bacterial Test Standard (BTS; Cat. No. 8255343). Additional items required: ( j )  Incubators.— Capable of maintaining temperatures of 34– 38°C. ( k ) Pipets .—Adjustable, variable volume, capable of sampling and delivering 1–1000 µL. ( l ) Micropipet tips.— Aerosol-resistant. ( m ) Refrigerator.— Capable of maintaining 2–8°C. ( n ) Freezer.— Capable of maintaining –20°C. ( o ) Tryptic soy agar (TSA) .—Standard formulation. ( p ) Xylose lysine deoxycholate (XLD). —Standard formulation. ( q ) Brilliant green sulfa agar (BGSA). —Standard formulation. ( r ) RAPID’ Salmonella agar (RSA).— Bio-Rad. ( s ) AES Salmonella agar plate (ASAP ® ). ( t ) Brilliance TM Salmonella agar (BSA) .—Thermo Fisher Scientific. ( u ) Enterobacter sakazakii isolation agar (ESIA). —Standard formulation. ( v ) Chromogenic Cronobacter isolation (CCI) agar. —Standard formulation. ( w )  Columbia blood agar (CBA) .——Standard formulation. ( x )  Modified charcoal cefoperazone deoxycholate agar (mCCDA) .—Standard formulation. ( y )  Campy Cefex agar (CCA) .—Standard formulation. ( z )  RAPID’Campy agar (RCA) .—Bio-Rad.

( aa )  CampyFood agar (CFA) . ( bb ) Vortex mixer. ( cc ) Bench-top microcentrifuge.— Eppendorf centrifuge, Model No. 5424R or equivalent, capable of 15871 to 21130 g . ( dd ) Standard solvent.— Acetonitrile 50%, water 47.5%, and trifluoroacetic acid 2.5%. ( ee ) Water .—HPLC grade. ( ff ) Formic acid. ( gg ) McFarland standards. ( hh ) Absolute ethanol. ( ii ) Guanidine hydrochloride (GdnHCl).— 8 M, commercially available. ( jj ) Trifluoroacetic acid. ( nn )  Fiber-free cloth .—For cleaning MSP 96 target polished steel BC (Cat. No. 8280800) or MSP 48 target polished steel BC (Cat. No. 8281817). C. General Preparation ( a ) Isolation of organisms for testing .—Organisms for testing must be isolated on one of the recommended media. Refer to the MALDI Biotyper System Quick Guide for Food Testing (No. 1855438) for a list of recommended isolation media ( Salmonella species: XLD, BGSA, RSA, BSA, and ASAP, or any nonselective ( kk ) Colony transfer device. ( ll ) Inoculation loops.— Sterile. ( mm ) Microcentrifuge tubes .—1.5 mL.

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