Disease prevention plays a fundamental role in addressing challenges in the poultry industry, specifically those related to food safety. Disease outbreaks and foodborne illnesses often result in significant economic losses. Salmonella colonization in poultry pose an increased risk of carcass contamination and disease transmission to humans. Human salmonellosis alone can cost an estimated $3 billion per year in production losses and medical care (Scharff, 2020). Current industry approaches to prevent disease include pest control, vaccination, antibiotic alternatives, feed sanitation, and intensive biosecurity programs.
Effective cleaning and disinfection protocols are a crucial part of any biosecurity program. Removal of bacteria and organic matter, however, can be challenging with standard water-based cleaning agents and spray applicators (Bredholdt et al., 1999). Insufficient product contact time, accumulation of organic material, and the application process can severely impact the efficacy of cleaning agents (Chlibek et al., 2006; Karsten, 2021). Foaming agents are routinely used to clean poultry processing plants and hatcheries, as foams reduce the surface tension of water-based cleaners and prevent droplet formation. This results in improved product coverage and may assist with breakdown of organic material (Chlibek et al., 2006; White et al., 2018).
Compressed air foam systems (CAFS) generate pressurized foams and may serve as an alternative application strategy for cleaning agents. Previous studies have demonstrated the ability of CAFS applied foaming agents to clean and disinfect broiler transportation coops and layer cages. Treatment of transport coops with peracetic acid and a chlorine-based foaming cleaner significantly reduced aerobic bacteria and Salmonella Typhimurium (Hinojosa et al., 2018). In another study, peroxyacetic acid and glutaraldehyde-based disinfectants significantly reduced aerobic bacteria in layer cages (White et al., 2018). The structural similarities between broiler transport coops, layer cages and caged quail facilities provide support for the incorporation of this technology in commercial quail housing. Originally patented by Spielholtz (1988), CAFS application of foaming agents occurs rapidly and may serve as a novel method to clean and sanitize quail rearing facilities.
The objective of this study was to evaluate the efficacy of a CAFS applied commercially available firefighting foam (FF) and chlorine-based foaming cleaner (FC) in quail floor pen and caged rearing facilities. These facilities experienced a history of rodent infestation and correlated Salmonella enterica serovar Typhimurium contamination. We hypothesized that the use of a CAFS to apply the firefighting foam and foaming cleaner would significantly reduce aerobic bacteria and microbial adenosine triphosphate (ATP) in both floor pen and caged housing.
MATERIALS AND METHODS
Experimental Design
All protocols and procedures for this study were approved by the Texas A&M University Institutional Biosafety Committee (IBC). Texas A&M white coturnix quail field trials were conducted in floor pen and caged facilities on a farm 1 mo apart. Prior contamination of the farm with Salmonella Typhimurium due to a significant rodent infestation resulted in a 12-mo layout period without birds. Grow out barns resembled an older style, curtain-sided broiler barn. Birds were reared on wood shavings and dried manure. The caged facility was analogous to a conventional caged chicken egg laying facility, although it was used as a colony breeding system to produce fertile quail eggs. A large population of mice remained in the facility and were seen emerging from the litter during the day, which was surprising for a mammal that is considered nocturnal and neophobic.
In the first trial, FF and FC were applied to 2 separate 80 × 80 ft (24.38 × 24.38 m) floor pen barns. Each product was allowed a 30 min contact time prior to a water rinse and sample collection. Environmental (n = 20) and ATP (n = 20) swabs were collected (pre- and post-treatment) from the walls, metal rails, and posts in each barn. The same treatments were applied to 2 separate 80 × 80 ft (24.38 × 24.38 m) caged quail houses in the second trial. Environmental (n = 20) and ATP (n = 20) swabs were collected (pre- and post-treatment) from the cages and manure belts in each barn.
Treatment Application
Two commercial foam concentrates were diluted in water according to manufacturer’s recommendations. A 1.5% FF solution (Phos-Check WD881, ICL Performance Products LP, Rancho Cucamonga, CA) was prepared by diluting 4.5 gal (17 L) of foam concentrate in 300 gal (1,136 L) of water. A 3% FC solution (Chlor-A-Foam XL, DuPont, Houston, TX) was prepared by diluting 9 gal (34 L) of the cleaner in 300 gal (1,136 L) of water. The FF was comprised of a proprietary blend of ammonium phosphate salts while the FC contained a proprietary blend of 5% to 10% potassium hydroxide and 1% to 3% sodium hypochlorite. Application of the FF and FC in each rearing facility was achieved using a CAFS (Rowe CAFS, Hope, AR). The system was comprised of a 40-horsepower gasoline engine, a 150 gal (568 L) per min water pump, a 70 CFM rotary screw compressor, and could produce 495 gal (1,874 L) of foam per min.
Environmental Sample Collection
Surface swabs were used to sample regions of the floor pen and caged facilities for recovery of aerobic bacteria. Paired samples were collected pre- and post-treatment of either facility with the FF and FC. In the floor pen rearing facility, surface swabs were taken from the walls (n = 8), rails (n = 8), and posts (n = 4). In the caged rearing facility, swabs were taken from the cages (n = 16) and manure belts (n = 4). Sterile 2 × 2 in (5 × 5 cm) swabs were presoaked with 10 mL of buffered peptone water (BPW) in sterile 4 oz (118-mL) Whirl-Pak bags (Nasco, Fort Atkinson, WI). A 2 × 2 in (5 × 5 cm) stainless steel template was used to collect a uniform sample area. The templates were sprayed with 95% ethanol and flame sterilized. Excess BPW was squeezed from each swab prior to sample collection using a newly gloved hand. Four horizontal and 4 vertical movements were made across the template before returning to respective sample bags. Samples were stored on ice and transported to the lab for processing. All samples were homogenized in a stomacher blender (Seward, Port Saint Lucie, FL) for 30 s at normal speed. The blended samples were serially diluted in phosphate buffered saline and plated on tryptic soy agar (Beckton-Dickinson and Company, Franklin Lakes, NJ). Plates were incubated at 37°C for 24 h prior to bacterial enumeration. Total counts were reported as log10 CFU/mL.
Adenosine Triphosphate Bioluminescence
ATP swabs were used to quantify the level of cellular ATP in the floor and caged rearing facilities. Samples were collected concurrently and adjacent to the environmental surface swabs using the same sterile 2 × 2 in (5 × 5 cm) stainless steel templates. UltraSnap ATP swabs (Hygiena, Camarillo, CA) were used to make 4 horizontal and 4 vertical movements across the 2 × 2 in (5 × 5 cm) sample area. The end of the swab was snapped to release the luciferase reagent prior to vertical insertion into a SystemSURE II Luminometer, 18395 (Hygiena, Camarillo, CA). A threshold value of 30 RLU was set as the limit of detection, per manufacturer’s instructions. Samples were processed according to the manufacturer’s instructions and ATP measurements were recorded as relative light units (RLU).
Statistical Analysis
Aerobic bacteria colony counts were converted to log10 CFU/mL for statistical analysis. Adenosine triphosphate swab readouts were reported as the mean RLU value per sample. Reductions in total aerobes and cellular ATP were subjected to a Paired Samples t-Test using JMP Pro 15 (SAS Institute Inc., Cary, NC). Differences across treatments were analyzed using a 1-way ANOVA using the least squares model. Means were deemed significantly different at P ≤ 0.05.
RESULTS AND DISCUSSION
Compressed air foam systems (CAFS) generate high velocity foams that may serve as a carrier for cleaning agents to clean and sanitize quail rearing facilities following an outbreak. Trial 1 evaluated the ability of a CAFS applied FF and FC to reduce total aerobes and microbial ATP levels in floor pen quail rearing facilities (Figure 1A and B). Both the chlorine-based foaming cleaner and the commercial firefighting foam significantly reduced aerobic bacteria after treatment (P < 0.05). Reductions were 1.74 and 0.85 log10 CFU/mL with the FC and FF treatments, respectively. Significant reductions in microbial ATP were also reported with each treatment in the floor pen facility (P < 0.05). Treatment with FC and FF reduced RLU by 2,871 and 4,201 units, respectively.
Figure 1. Reduction of aerobic bacteria and microbial ATP following treatment of floor pen facilities. Significant reductions in aerobic bacteria (A) and ATP levels (B) were reported after treatment of a floor pen facility with a commercial firefighting foam and a foam-based cleaner. Mean log10 CFU/mL (n = 20) and RLU (n = 20) values with varying superscripts differ significantly (P ≤ 0.05).
Trial 2 evaluated the ability of the CAFS applied FF and FC to reduce total aerobes and microbial ATP in caged rearing facilities (Figure 2A and B). Both the chlorine-based foaming cleaner and the commercial firefighting foam significantly reduced aerobic bacteria after treatment (P < 0.05). Reductions were 1.04 and 0.87 log10 CFU/mL with FC and FF treatments, respectively. Significant reductions in microbial ATP were also reported with each treatment in the caged facility (P < 0.05). Treatment with FC and FF reduced RLU by 2,763 and 3,084 units, respectively.
Figure 2. Reduction of aerobic bacteria and microbial ATP following treatment of caged facilities. Significant reductions in aerobic bacteria (A) and ATP levels (B) were reported after treatment of a caged facility with a commercial firefighting foam and a foam-based cleaner. Mean log10 CFU/mL (n = 20) and RLU (n = 20) values with varying superscripts differ significantly (P ≤ 0.05).
The use of CAFS to apply foam-based cleaners in poultry rearing facilities presents several advantages to traditional water-based cleaners. Foams reduce the high-surface tension associated with water-based cleaners resulting in uniform application of cleaning agents and improved contact time (Chlibek et al., 2006; White et al., 2018). Pressurized foam applications may also assist with the physical removal of microbes through the breakdown of organic material. The objective of this study was to evaluate the effects of CAFS applied FF and FC in floor pen and caged quail rearing facilities with a history of salmonellosis. All treatments resulted in a significant reduction in total aerobes (P < 0.05), however, the greatest reductions were consistently observed with the FC treatment of either rearing system (P < 0.05). Although neither product was labeled as a disinfectant, the chlorine-based cleaner contained sodium hypochlorite which was expected to exhibit antimicrobial activity through protein oxidation (Valera et al., 2009; Karsten, 2021). Hinojosa and colleagues reported a significant reduction in aerobic bacteria following treatment of broiler transport coops with a similar CAFS applied chlorine-based foaming cleaner (Hinojosa et al., 2018). Treatment of the floor pen and caged facilities with the FC resulted in significant reductions of 1.74 and 1.04 log10 CFU/mL, respectively. Caged facilities may harbor increased organic material in crevices and on manure belts providing the appropriate environment for microbial growth (White et al., 2018). A multistep process that incorporates removal of organic matter prior to cleaning could be advantageous as excess material can reduce the efficacy of cleaning agents (Stringfellow et al., 2009; Karsten, 2021). These findings were supported by a previous study where the inclusion of a high-pressure water rinse improved the reduction of aerobic bacteria on broiler transport coops (Hinojosa et al., 2018).
The ability of a CAFS applied FF and FC to reduce microbial ATP in floor pen and caged facilities was also analyzed. Microbial ATP levels were reported as relative light units (RLU). All treatments resulted in a significant reduction in ATP bioluminescence (P < 0.05), however, above the target level of 30 RLU. The greatest reduction of 4,201 RLU was reported following FF treatment of the floor pen facility. It is important to note that the FF treated floor pens and caged facilities exhibited higher pretreatment microbial ATP levels allowing for greater total reductions. Additionally, microbial ATP levels account for a microbial population that encompasses more than aerobic bacteria. Whether the overall reduction can be attributed to the physical or chemical elimination of microbes is unclear. The commercial firefighting foam was not labeled as a disinfectant; however, the product did contain a low concentration of d-Limonene which was expected to exhibit broad-spectrum, antibacterial activity. (Han et al., 2019).
The exclusion of a nontreatment control group prevented the comparison of natural shifts or reductions in the microbial population and reductions attributed to foam treatment. Additional studies that include this control group would more accurately convey the efficacy of the CAFS applied foaming agents. Nevertheless, both the commercial firefighter foam and the foaming cleaner significantly reduced aerobic bacteria and microbial ATP levels in floor pen and caged quail facilities, relative to the pretreatment negative controls.
Overall, this study demonstrated the efficacy of CAFS applied FF and FC in previously contaminated quail rearing facilities. Both treatments significantly reduced total aerobes and microbial ATP levels in floor pen and caged housing. These data suggest that a compressed air foam system can serve as an effective application method for foaming agents to clean poultry rearing facilities prior to disinfection.
Source: Science Direct
