TABLE 3.
Total aerobic viable counts and Staphylococcus aureus counts from larvae and substrate (chicken feed) samples
| Experimental conditiona | Sample | Target S. aureus contamination level in chicken feed (log CFU/g) | Total viable count (log CFU/g)b |
S. aureus count (log CFU/g)b |
||||
|---|---|---|---|---|---|---|---|---|
| Day 0 | Day 2 | Day 6 | Day 0 | Day 2 | Day 6 | |||
| CF | Substrate | Control | 4.0 ± 0.1 A | 9.8 ± 0.2 B | 10.2 ± 0.1 C | <2.0† A | <2.0† A | <2.0† A |
| CF + L | Substrate | Control | 3.7 ± 0.1 A | 10.1 ± 0.1 B | 10.6 ± 0.2 C | <2.0† A | <2.0† A | <2.0† A |
| CF + L | Larvae | Control | 8.6 A | 9.6 ± 0.3 B | 9.6 ± 0.2 B | <2.0† A | <2.0† A | <2.0† A |
| CF + P | Substrate | 3 | 4.6 ± 0.4 A | 9.6 ± 0.1 B | 10.1 ± 0.1 C | 3.8 ± 0.1 A | 3.7 ± 0.4 A | <3.0 ± 0.1° B |
| CF + P + L | Substrate | 3 | 5.0 ± 0.2 A | 10.0 ± 0.1 B | 10.6 ± 0.1 C | 3.5 ± 0.2 A | <2.1 ± 0.2° B | <2.0 ± 0.0° B |
| CF + P + L | Larvae | 3 | 8.3 A | 9.1 ± 0.1 B | 9.1 ± 0.2 B | <2.0† A | <2.0† A | <2.0† A |
| CF + P | Substrate | 7 | 7.3 ± 0.2 A | 9.3 ± 0.1 B | 10.3 ± 0.3 C | 7.2 ± 0.2 A,B | 8.0 ± 0.2 B | <6.2 ± 0.8° A |
| CF + P + L | Substrate | 7 | 7.3 ± 0.3 A | 10.1 ± 0.1 B | 11.1 ± 0.5 C | 7.3 ± 0.1 A | 4.7 ± 0.8° B | <3.1 ± 1.2° B |
| CF + P + L | Larvae | 7 | 7.3 ± 0.3 A | 9.4 ± 0.8 B | 9.2 ± 0.2 B | <2.0† A | <2.7 ± 0.6° A | <2.0† A |
CF, chicken feed; CF + P, chicken feed with pathogen; CF + L, chicken feed with larvae; CF + P + L, chicken feed with pathogen and larvae.
Results are presented as the mean ± standard deviation of six replicates per condition. Average values for total viable counts and S. aureus counts within each row that share a letter (A, B, C) did not significantly (P ≥ 0.05) increase or decrease between sampling days. The notation “<2.0†” indicates that Staphylococcus aureus was below the detection limit (2.0 log CFU/g) in every sample. The ° notation with a value higher than 2.0 log CFU/g indicates that the S. aureus count was below the detection limit (varying between 2.0 log CFU/g and 5.0 log CFU/g) in at least one sample but not all samples.