TABLE 2.
Presence of nisin in the gastrointestinal tract of HFA rats estimated by a biological assay and a competitive immunoassay
| Sampling source | Nisin dose (mg)a | Time after dosage (h) | Nisin concn (μg/g intestinal or fecal content) byb:
|
|
|---|---|---|---|---|
| Biological assay | Competitive immunoassay | |||
| Duodenum | 60 | 3 | 1.8 ± 0.1 | 18.9 ± 5.6 |
| Ileum | 60 | 3 | 6.9 ± 1.5 | 62.4 ± 16.1 |
| Cecum | 60 | 3 | <LD | <LD |
| Colon | 60 | 3 | <LD | <LD |
| Fecesc | 60d | 24 | 0.4 ± 0.5 | 76.8 ± 18.2 |
| 0.6e | 24 | <LD | 5.5 ± 1.4 | |
a
The concentrations of nisin were below the LD for intestinal and fecal samples from rats inoculated with PBS (data not shown).
b
LD, limit of detection. The LD was 50 ng/g for the biological assay and 5 ng/g of intestinal or fecal content for the competitive immunoassay.
c
Fecal samples other than the intestinal samples were obtained from other rats.
d
Nisin was detected in the two rats inoculated with 60 mg nisin.
e
Nisin was detected in only one of three rats inoculated with 0.6 mg nisin, which corresponds to the nisin concentration approved for use in food by the European Union (European Parliament and Council Directive 95/2/EC).