Chemical, Biological, and Physical Methods
243
Table 11–1 (continued)
Methods
Toxin or Organism
Sensitivity
ELISA
Staph. Enterotoxin A in wieners
0.4 ng
Staph. enterotoxins A, B, and C
in foods
0.1 ng/ml
Staph. enterotoxins A, B, C, D,
and E in foods
≥1ng/g
Botulinal toxin type A
About 9 mouse LD 50 /ml with
monoclonal antibody
Botulinal toxin type A
50–100 mouse i.p. LD 50
Botulinal toxin type E
100 mouse LD 50
Aflatoxin B 1
25 pg/assay
Aflatoxin M 1 in milk
0.25 ng/ml
Aflatoxin B 1
<1 pg/assay
Salmonellae
10
4 –10
5 cells/ml
AFB 1
0.2 ng/ml (monoclonal)
AFB 1
0.4 ng/ml (polyclonal)
AFM 1
1.0 ng/ml (monoclonal)
Fumonisins in feed
250 ng/g
Zearalenone in corn
1 ng/g
E. coli O157:H7 in ground beef
<1 cell/g
C. perfringens enterotoxin
1 pg/ml
AFB 1 in peanut butter
2.5 ng/g
Ochratoxin in barley
1 ng/ml
Polymerase chain
reaction (PCR)
E. coli
1–5 cells/100 ml H 2 O
E. coli
1 cell
L. monocytogenes
1–10 cells
V. vulnificus
10
2 cfu/g (oysters)
C. perfringens
<1 cfu, 2–6 hours
Stx1 and Stx2 of E. coli
1 cell/g in 12 hours
C. botulinum toxins A to E
10 fg (∼3 cells)
Y. enterocolitica
10–30 cfu/g meat
Fluorogenic PCR-based
assay
E. coli
0.5 cfu/g
Real-time PCR
Listeria monocytogenes
1 cell
Real-time PCR
Giardia lamblia
1 oocyst
Probelia system
Salmonellae in foods
10
2 threshold sensitivity
RT-PCR
Cryptosporidium parvum
1 oocyte/l, 3 hours
Multiplex PCR
Listeria
1–5 cfu/25 g
Multiplex PCR
E. coli 0157:H7
<1 cfu/g
Fluorescent PCR assay
E. coli
3 cfu/25 g
Immunomagnetic
separation
E. coli O157:H7
<10
3 cfu/g
Ice nucleation
Salmonellae
ca. 25/g
∗ HPR, exothermic heat production rate.