Preparation of immunomagnetic iron-dextran nanoparticles and application in rapid isolation of E.coli O157:H7 from foods

Table 1 Effect of oxidation time on recovery (n = 5, mean±SD).

Oxidation time (h)	Colony forming unit (CFU/mL)	Recovery1 (%)
0.5	9.60±1.82	9.80±1.85
1.0	17.80±2.68	18.16±2.74
2.0	26.60±3.78	27.14±3.86
4.0	61.60±6.47	62.86±6.60
6.0b	89.60±4.93	91.43±5.03
8.0	70.20±5.76	71.63±5.88
10.0	65.00±5.39	66.33±5.50
12.0	60.20±4.32	62.24±4.41

^bP<0.01 vs other oxidation time.

¹There were 98 CFU/mL in the dilution (mean of five samples).

Table 2 Effect of amount of antibody on recovery (n = 5, mean±SD).

Amount of antibody (mg/mg particles)	Colony forming unit (CFU/mL)	Recovery1 (%)
5	32.20±5.54	33.54±5.77
10	48.00±5.34	50.00±5.56
15	49.20±7.36	51.25±7.67
20	68.80±4.09	71.67±4.26
25b	89.60±4.16	93.33±4.33
30	75.00±6.75	78.13±7.03
35	64.80±4.87	67.50±5.07
40	54.00±4.64	56.25±4.83
45	47.80±6.06	49.79±6.31
50	33.80±6.83	35.21±7.12

^bP<0.01 vs other amount of antibody.

¹There were 96 CFU/mL in the dilution (mean of five samples).

Table 3 Effect of amount of nanoparticles on recovery (n = 5, mean±SD).

Amount of nanoparticles (µL)	Colony forming unit (CFU/mL)	Recovery1 (%)
5	88.60±4.93	92.29±5.13
10	87.60±4.04	91.25±4.21
15	88.20±6.06	91.88±6.31
20	88.40±4.04	92.08±4.21
25	90.20±4.32	93.96±4.50
30	89.00±5.61	92.71±5.85

¹There were 96 CFU/mL in the dilution (mean of five samples).

Table 4 Effect of incubation time on recovery (n = 5, mean±SD).

Incubation time(min)	Colony forming unit (CFU/mL)	Recovery1 (%)
5	45.80±5.63	41.26±5.07
10b	96.80±7.26	87.21±6.54
15	101.40±9.94	91.35±8.95
20	98.00±8.37	88.29±7.54
30	98.40±8.05	88.65±7.25
40	101.00±7.14	90.99±6.43
50	99.80±8.61	89.91±7.76
60	98.80±7.29	89.01±6.57

^bP<0.01 vs 5 min of incubation time.

¹There were 111 CFU/mL in the dilution (mean of five samples).

Table 5 Effect of magnetic separation time on recovery (n = 5, mean±SD).

Magnetic separation time (min)	Colony forming unit (CFU/mL)	Recovery1 (%)
1	40.80±6.91	42.50±7.19
2b	88.20±6.30	91.88±6.56
3	90.00±5.70	93.75±5.94
4	91.00±6.89	94.79±7.18
5	90.40±5.59	94.17±5.83

^bP<0.01 vs 1 min of magnetic separation time.

¹There were 96 CFU/mL in the dilution (mean of five samples).