Table 2.
Main effects of feed manufacturing surface type and decontamination treatment on cycle threshold quantification of porcine epidemic diarrhea virus RNA with environmental swabbing1,2
| Main effect | Cycle threshold, Ct | SEM | P = |
|---|---|---|---|
| Surface | 0.23 | < 0.0001 | |
| Cement | 31.5a | ||
| Polyethylene | 28.5b | ||
| Woven polyethylene | 31.4a | ||
| Rubber | 28.0b | ||
| Stainless steel | 28.8b | ||
| Decontamination treatment | 0.32 | < 0.0001 | |
| Control | 26.2e | ||
| Rice hulls (RH) | 26.7d,e | ||
| Formaldehyde RH3 | 26.2e | ||
| Formaldehyde4 | 42.9a | ||
| Benzoic acid/essential oil5 | 27.8c,d | ||
| Food-grade sanitizer6 | 26.3e | ||
| Peroxide7 | 26.5d,e | ||
| Quaternary ammonium/glutaraldehyde8 | 28.4c | ||
| Sodium hypochlorite9 | 38.2b | ||
| MCFA10 | 27.4c,d,e |
1 A total of 150 surface samples were used in a 5 × 10 factorial arrangement using five surface types, 10 chemical treatments, and three replicates per surface type × chemical treatment combination. One mL (1 × 105 TCID50/mL) of stock PEDV was applied to each surface and allowed to dry completely for 60 min. The chemical treatments were then applied and allowed a 15 min contact time after which excess was removed. Surfaces were then swabbed using pre-moistened environmental swabs in 5 mL of neutralizing broth. Swabs were then analyzed using a quantitative, real-time, reverse-transcriptase PCR analytical procedure.
2 Treatment × surface, P < 0.0001. Interactive means presented in Table 1.
3 Rice hulls treated with commercial formaldehyde (3.25 kg/tonne; Sal CURB; Kemin Industries, Des Moines, IA; 30% formaldehyde and 10% propionic acid/methanol blend).
4 Sal CURB (Kemin Industries, Des Moines, IA).
5 VevoVitall and CRINA (25:1 ratio; DSM Nutritional Products Inc., Parsippany, NJ; 96% benzoic acid and 4% essential oil blend).
6 DrySan Duo (Ecolab, St. Paul, MN; 10.98% isopropyl alcohol, 0.045% hydrogen peroxide, 0.016% alkyl dimethyl benzyl ammonium chloride, 0.007% dodecyl dimethyl ammonium chloride, and 0.005% dioctyl dimethyl ammonium chloride).
7 Intervention (3% dilution; Virox Technologies Inc., Ontario, Canada, 4.25% hydrogen peroxide).
8 Synergize (0.39% dilution; Preserve International, Reno NV; 26.0% alkyl dimethyl benzyl ammonium chloride and 7% glutaraldehyde).
9 Household bleach (10% dilution; The Chlorox Company, Oakland, CA; 8.25% sodium hypochlorite).
10 1:1:1 blend of ≥ 98% purity C6:0, C8:0, and C10:0 (Sigma Aldrich; St. Louis, MO).
Within main effect, means lacking a common lowercase letter are different (P < 0.05).