Quantification of Salmonella Infantis transfer from transport drawer flooring to broiler chickens during different lairage times

Authors: REINA, MARCO - Auburn University; MCCONNELL, ABIGAIL - Auburn University; FIGUEROA, JUAN - Auburn University; RIGGS, MONTANA - Auburn University; JENNINGS, MADALYN - Auburn University; CONTRERAS, FANNY - Auburn University; HUGHES, MATTHEW - Auburn University; Buhr, Richard - Jeff; BOURASSA, DIANNA - Auburn University

Submitted to: Poultry Science Association Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 5/23/2023
Publication Date: 7/10/2023
Citation: Reina, M., Mcconnell, A., Figueroa, J., Riggs, M., Jennings, M., Contreras, F., Hughes, M., Buhr, R.J., Bourassa, D. 2023. Quantification of Salmonella Infantis transfer from transport drawer flooring to broiler chickens during different lairage times. Poultry Science Association Meeting Abstract. 102(E-Suppl.1): 144, p.71..

Interpretive Summary:

Technical Abstract: Transportation is a potential point of cross contamination between broiler flocks. The objective of this study was to quantify the transfer of Salmonella from transport drawer perforated flooring to broiler chickens during different lairage times. Perforated plastic transport drawers (1.20 x 1.27 x 0.23 m) and their corresponding metal modules typical for controlled atmosphere stunning systems were used for this study. The internal area of each drawer was reduced to approximately 1 m2 to accommodate only 15 birds. Then the available area was inoculated with 100 g of 7 log10 CFU/g of Salmonella Infantis fecal content slurry and held at room temperature (21°C) for 1 h prior to three different cleaning treatments. Treatments were pressure washing combined with a commercial disinfectant (A), pressurized steam followed by forced hot air (B), and no cleaning (C). The 3 drawers per treatment were classified as top, middle, or bottom as their position in module. Then the birds were introduced and held for 2, 4, or 6 h. At each timepoint, 5 birds were removed from each drawer, euthanized, carcasses rinsed, and counts of Salmonella were obtained from the rinsates. Negative samples were enriched and later confirmed positive or negative. After two repetitions of the trial, counts were log transformed and the effects of treatment, time, and drawer position were analyzed by ANOVA with Tukeys HSD for mean separation. Significant differences were found among treatments, times, and drawer positions (P<0.0001). For the treatments, all were significantly different where C showed the highest transfer (2.47±0.06 log10 CFU/mL), followed by A (1.72±0.08 log10 CFU/mL), and then B (1.32±0.09 log10 CFU/mL). For time, the highest transfer was at 2 h, followed by 4 h, and then by 6 h (2.09±0.09, 1.90±0.10, 1.51±0.08 log10 CFU/mL respectively). For drawer position, the top drawers showed the least amount of transfer, followed by the middle drawers, and then by the bottom drawers (2.17±0.06, 1.93±0.08, 1.41±0.11 log10 CFU/mL, respectively). Despite obtaining lower transfer counts from the application of pressure washing combined with a commercial disinfectant (A) and pressurized steam followed by forced hot air (B) when compared to non-cleaning (C), all carcasses were positive for Salmonella. Cleaning and disinfecting transport drawers with the evaluated methods reduced but did not eliminate the transfer of Salmonella to subsequent birds. As 90% of birds were contaminated after being introduced into the drawers, this study evidence that transport cages and drawers are a critical point of cross-contamination during transportation and lairage, and new procedures need to be considered to efficiently control this step of the process.