From hatch to egg grading: monitoring of Salmonella shedding in free-range egg production systems

Table 1 Proportion of Salmonella positive samples and MPN quantification: Flock A

	Floor	Dust	Nest box	Egg belt	Eggs
16 weeks
Proportion	0	0.10 ± 0.10	0	0	0
MPN/m²	NM	3.0^a	NM	NM	NM
28 weeks
Proportion	0.10 ± 0.10	0.50 ± 0.17	0.50 ± 0.17	0.50 ± 0.17	0
MPN/m²	43^a	436.5 ± 237.5	248.4 ± 213.4	9.7 ± 6.7	NM
34 weeks
Proportion	0	0	0	0	0.20 ± 0.13
MPN/m²	NM	NM	NM	NM	12.8 ± 0.4
40 weeks
Proportion	0	0	0.10 ± 0.10	0.10 ± 0.10	0
MPN/m²	NM	NM	3.0^a	3.0^a	NM
46 weeks
Proportion	0	0.10 ± 0.10	0.20 ± 0.13	0.10 ± 0.10	0
MPN/m²	NM	4.3^a	1205 ± 1195	3.0^a	NM
52 weeks
Proportion	0	0.40 ± 0.16	0.10 ± 0.10	0.10 ± 0.10	0
MPN/m²	NM	3.0 ± 0.0	3^a	9.2^a	NM
58 weeks
Proportion	0	0.10 ± 0.10	0	0.10 ± 0.10	0
MPN/m²	NM	9.2^a	NM	43^a	NM
64 weeks
Proportion	0.10 ± 0.10	0	0.10 ± 0.10	0.20 ± 0.10	0
MPN/m²	210^a	NM	43^a	3.0 ± 0.0	NM
70 weeks
Proportion	0	0.10 ± 0.10	0	0	0
MPN/m²	NM	9.2^a	NM	NM	NM

Data are presented for each sample type as the proportion of Salmonella positive samples (± the standard error of the mean) and most probable number (MPN) (± the standard error of the mean).
^aOnly a single Salmonella positive sample was obtained.

ISSN: 1297-9716