3M E. coli O157 Gebrauchsanweisungen Seite 5

Foods
1. Pre-warm BPW ISO enrichment medium to 41.5 ± 1°C.
2. Aseptically combine the enrichment medium and sample according to Tables 2, 3 or 4. For all meat and highly
particulate samples, the use of filter bags is recommended.
3. Homogenize all matrices except leafy produce and fruit, thoroughly by blending, stomaching, or hand mixing for 2 ±0.2
minutes. Incubate at 41.5 ± 1°C for the appropriate time according to Tables 2, 3 or 4.
Table 2. General enrichment protocols
Sample Matrix
Raw beef including ground/mince and trim
Raw meats including raw beef, pork, poultry,
lamb, and bison
Leafy produce
Other foods including fruit
fruit/vegetable juices, fresh herbs, raw
seafood, raw eggs, raw milk, cookie dough,
and processed meats
Walnuts or nut mixes containing walnuts
(this protocol is appropriate for other nuts
including pecans, almonds, pistachios,
cashews, and chestnuts,
(a) Frozen samples should be equilibrated to 4-8°C before addition to enrichment broth.
(b) Leafy produce and fruit samples should be gently agitated by hand for 5 minutes. Do not blend or stomach.
Specific Instructions for Validated Methods
AOAC® Official Methods of Analysis
In AOAC Official Method of Analysis
found to be an effective method for the detection of E. coli O157:H7. The matrices tested in the study are shown in Table 3.
Table 3. Enrichment protocols using pre-warmed BPW ISO at 41.5 ± 1°C according to AOAC
Sample Matrix
Raw ground beef (73% lean)
Raw bagged spinach
(a)
Fresh sprouts
Frozen blueberries
(a)(b)
(a) Leafy produce and fruit samples should be gently agitated by hand for 5 minutes. Do not blend or stomach.
(b) Frozen samples should be equilibrated to 4-8°C before addition to enrichment broth.
Sample Size
(a)
325 g
25 g
200 g
(b)
, vegetables,
(b)
25 g
25 g
2017.01
SM
program, the 3M Molecular Detection Assay 2 – E. coli O157 (including H7) was
SM
Enrichment Broth
Sample Size
Volume (mL)
325 g 975
450
200 g
225
25 g
25 g 225
Enrichment Broth Volume
(mL)
975
BPW ISO
(pre-warmed)
225
BPW ISO
(pre-warmed)
450
BPW ISO
(pre-warmed)
225
BPW ISO
(pre-warmed)
225
reconstituted
non-fat dry milk
Enrichment Time
(hours)
10-18
18-24
18-24
18-24
4
(English)
Enrichment
Enrichment
Temperature
Time (hours)
(±1°C)
41.5 10-18
41.5 8-18
41.5 18-24
41.5 18-24
41.5 18-24
Official Methods 2017.01
® SM
Homogenized
Manually by hand or by
Stomach
Gently agitated by hand for 5
minutes, do not homogenize
Gently agitated by hand for 5
minutes, do not homogenize
Gently agitated by hand for 5
minutes, do not homogenize