AOAC 2019 First Action Methods

salmon offcuts, mixed precooked vegetables, mixed salad and process water (25 g) .― Add 225 mL LPT broth. Homogenize and incubate at 35 or 37 ± 1°C for 22–26 h. ( b ) Whole liquid eggs (100 mL) .― Add 900 mL of pre-warmed LPT broth. Homogenize and incubate at 35 ± 1°C for 22–26 h. ( c ) Deli ham and smoked salmon (125 g) .― Add 375 mL of LPT broth. Homogenize and incubate at 35 ± 1°C for 24– 28 h. ( d ) Whey powder (375 g) .― Add 1125 mL of pre-warmed LPT broth. Homogenize and incubate at 35 ± 1°C for 24– 28 h. ( e ) Environmental samples .―Add enough LPT broth to cover the sampling device (ex. 10 mL for a swab and 100 mL for a sponge). Homogenize and incubate at 35 or 37 ± 1°C for 22–26 h. Note : For environmental samples, the collection device should first be dampened with a sterile diluent (e.g., LPT broth) containing, if necessary, a suitable neutralizing agent (e.g. Lecithin-Polysorbate-L- Histidine-Sodium thiosulfate mixture or Dey Engley Neutralizing buffer). E. Sample Lysis ( a ) Following incubation, manually mix the contents of the blender bag. Optionally, a sterile technique can be used to remove 1 mL of enriched sample; place it in a pre-labeled microcentrifuge tube. Note : Do not discard the individual enriched samples until the analysis is complete and it has been confirmed that no further testing is required. Enriched samples can be stored at 2– 8°C for up to 72 h before performing analysis. ( b ) Use the plate map created in the GENE-UP® Routine software to determine the number of lysis tubes required from the GENE- UP® Lysis Kit and place the correct number of lysis tubes in the GENE -UP® Lysis Tube Holder. If less than 8 t ubes in a strip are required, the strips can be cut apart. Note : Never open the lysis tubes. If a lysis tube opens or leaks, this should be considered a contamination event. ( c ) Clip the GENE-UP® Lysis Tube Holder on the GENE-UP® Heavy Rack Holder. ( d ) Transfer 20 μL of sample into the lysis tube. Use the Plate Map from the GENE -UP® Routine software to pipet each sample into the correct plate position. ( e ) Remove the GENE-UP® Lysis Tube Holder from the GENE-UP® Heavy Rack Holder. ( f ) Clip the GENE-UP® Lysis Tube Holder on the Troemner Vortex Mixer Adaptor. ( g ) Run the vortex mixer at 2200 rpm for 5 m. Note : When using the Vortex-Genie® Pulse, fit it with the GENE-UP® Lysis Rack Adaptor. Run the vortex at maximum speed for 5 m. The maximum speed must be above 2000 rpm.