418 / 453
Table 5: Aerobic Plate Count and Background Results (Prior to Inoculation)
Matrix
APC
1
(CFU/g)
E. coli
STECPathogen Screen
1
Replicate
A
Replicate
B
Replicate
C
Replicate
D
Replicate
E
Fresh Spinach
1.4 x 10
6
None
Detected
None
Detected
None
Detected
None
Detected
None
Detected
Matrix
APC
1
(CFU/g)
E. coli
O157:H7 Pathogen Screen
2
Replicate
A
Replicate
B
Replicate
C
Replicate
D
Replicate
E
Raw Ground Beef
(70% Lean)
2.8 x 10
3
None
Detected
None
Detected
None
Detected
None
Detected
None
Detected
Matrix
APC
1
(CFU/g)
E. coli
STEC Pathogen Screen
1
Replicate
A
Replicate
B
Replicate
C
Replicate
D
Replicate
E
Raw Beef Trim
4.9 x 10
4
None
Detected
None
Detected
None
Detected
None
Detected
None
Detected
Screen
1
- Background screen conducted using BAX STEC Screen Kit
Screen
2
-Background screen conducted using AOAC approved LFD
Table 6A: MPN Summary Table for Fresh Spinach
Fresh Spinach (200 g)
E. coli
O111 MSUTW06315
Low Level Inoculum (0.2-2 MPN/Test Portion)
A
B
C
D
E
400 g
-
+
+
-
+
20 x 200 g (Reference Samples)
9/20
100 g
+
-
+
-
-
MPN/Test portion
0.61
Low Conf. Limit MPN/Test Portion
0.33
High Conf. Limit MPN/Test Portion
1.02
High Level Inoculum (2-5 MPN/Test Portion)
A
B
C
D
E
5 x 200 g (Reference Samples)
5/5
80 g
+
+
+
+
+
40 g
+
+
+
-
+
MPN/Test portion
3.70
Low Conf. Limit MPN/Test Portion
1.52
High Conf. Limit MPN/Test Portion
9.02
*
MPN was calculated for the low level inoculation for fresh spinach using five 400 g, twenty 200 g (reference
method test portions), five 100 g using the LCF MPN Calculator version 1.6 provided by AOAC-RI
http://www.lcfltd.com/customer/LCFMPNCalculator*
MPN was calculated for the high level inoculation for fresh spinach using five 200 g (reference method test
portions), five 80 g and five 40 g using the LCF MPN Calculator version 1.6 provided by AOAC-RI
http://www.lcfltd.com/customer/LCFMPNCalculatorOMAMAN-36 E/ AOAC PTM Report
ERP Use Only
January 2017
AOAC Research Institute
Expert Review Panel Use Only