Table 3.

Total aerobic viable counts and Salmonella sp. counts of larvae and substrate samples of experiment series 2, involving both a low (4 log CFU/g) and high (7 log CFU/g) contamination of resistant Salmonella strains and all conditions incubated in the same climate chamber. Values represent the mean (±standard deviation) of two batches, each with two replicates per condition (n = 2x2). S = Substrate; S + P = Substrate with pathogen; S + L = Substrate with larvae; and S + P + L = Substrate with pathogen and larvae.

Experimental condition	Investigated sample	Target Salmonella sp. contamination level in substrate (log CFU/g)	Total viable count (log CFU/g)				Salmonella sp. count (log CFU/g)
			Day 0	Day 2	Day 6		Day 0	Day 2	Day 6
S	Substrate	0*	5.2 ± 0.2a	9.6 ± 0.3b	10.0 ± 0.2b		<2.0 ± 0.0†a	<2.0 ± 0.0†,a	4.0 ± 1.3a
S + P	Substrate	4	5.0 ± 0.1a	9.5 ± 0.3b	10.0 ± 0.1b		3.6 ± 0.4a	<2.6 ± 0.7ǂ,a	5.9 ± 0.8a
S + P	Substrate	7	7.8 ± 0.2a	9.5 ± 0.5b	10.4 ± 0.2c		7.6 ± 0.1a	7.5 ± 1.1a	6.8 ± 1.3a
S + L	Substrate	0*	5.2 ± 0.2°,a	10.2 ± 0.0b	10.9 ± 0.4c		<2.0 ± 0.0°,†,a	<4.5 ± 2.5ǂ,a	6.2 ± 0.5a
S + P + L	Substrate	4	5.0 ± 0.1°,a	9.9 ± 0.2b	10.7 ± 0.3c		3.6 ± 0.4°,a	<4.7 ± 2.3ǂ,a	6.9 ± 0.7a
S + P + L	Substrate	7	7.8 ± 0.2°,a	10.4 ± 0.1a	11.7 ± 0.8a		7.6 ± 0.1°,a	7.8 ± 0.3a	7.5 ± 0.3a
S + L	Larvae	0*	8.2 ± 0.4a	8.6 ± 0.5a,b	9.2 ± 0.5b		<2.0 ± 0.0†,a	<4.2 ± 2.5ǂ,a	5.1 ± 1.6a
S + P + L	Larvae	4	8.2 ± 0.4a	8.8 ± 0.5a,b	9.1 ± 0.1b		<2.0 ± 0.0†,a	<4.3 ± 2.2ǂ,a	5.9 ± 0.4a
S + P + L	Larvae	7	9.0 ± 0.3a	9.1 ± 0.3a	9.6 ± 0.3a		<2.0 ± 0.0†,a	6.5 ± 0.3a	5.7 ± 0.1a

^*Uninoculated replicates; ° = sample is similar at this timepoint to chicken starter feed without larvae and was not determined a second time;

^†“<2.0” indicates that Salmonella sp. count was below the detection limit (2 log CFU/g) in every sample;

^ǂ“<” followed by a value higher than 2.0 log CFU/g indicates that Salmonella sp. count was below the detection limit in at least one, but not all samples; ^abc Average values for total viable counts and Salmonella sp. counts within each row that share a letter in superscript did not significantly (p ≥ 0.05) increase or decrease between sampling days.