Effectiveness of a comprehensive hygiene programme in controlling Salmonella
The effective cleaning and disinfection of broiler houses at the end of a production round is a crucial step in reducing the infection pressures on broiler farms and preventing both food-borne zoonoses and endemic animal diseases. Water treatment such as acidifying the drinking water with organic acids has shown also to reduce the Salmonella horizontal transmission in broiler chickens.
This study evaluated the impact of cleaning and disinfection of pullet and breeder houses both with the water hygiene on Salmonella prevalence and concentration at commercial broiler production facilities, including pullet, breeders and processing plant.
Materials and methods
Two pullet flocks with 18,000 birds each were placed into 2 commercial pullet houses as 1 control flock and 1 treated flock. Boot swabs were collected from each pullet house at 4, 8, 12, 20 weeks of age. At 22 weeks of age, pullets were transferred to 2 commercial breeder houses as 1 control and 1 treated flock. Boot swabs, drag swabs, litter, environmental swabs (slat, perch, egg belt and egg room) were collected at 30, 34, 38, and 42 weeks of age.
A total of 28,000 chicks originated from the control breeder flock and 28,000 originated from the treated breeder flock were raised for 49 days in 2 broilers houses as 1 control and 1 treated flock. The trial was conducted in an industrial farm in the southeast of the US.
The control and the treated flocks at various levels of production were submitted to different surface and water hygiene as presented (Table 1).
At the processing plant the rinsate of 15 carcasses from the control broiler flock and 15 carcasses from the treated broiler flock were sampled.
Samples from pullet houses received a Salmonella quantification using a miniature 4-tube most probable number (mMPN). The limited detection of MPN of the current method were 2.69 log MPN/boot swab, 2.09 log MPN/drag swab, and 1.39 log MPN/g of litter.
Samples from breeder houses and processing received a Salmonella prevalence evaluation using Hygiena TM BAX System Q7 following the instruction of manufacturer.
Results: poultry house – pullet and breeder phase
A decrease of the Salmonella population was noted over time at pullet phase in both control (from 2.87 to 1.58 log MPN/boot swab) and treatment (2.83 log MPN/boot swab to negative) flocks from 4 to 20 weeks of pullet age.
Salmonella prevalence in breeder houses environment (boot swab, drag swab and litter samples) was higher (p£0.05) with 79.2% during the 30 to 42 weeks of breeder age in the control house, compared to the treatment house (boot swab: 4.2%; drag swab: 0%; and litter: 4.2%). Additionally, the Salmonella prevalence in the boot swabs of control breeder house slats was higher (54.2%; p£0.05) than the treatment house (0%).
Results: processing plant
Salmonella prevalence before pre-chiller for the control group was higher (100%, p≤ 0.05) compared to the treatment group (33%, p≤ 0.05).
Conclusion
Cleaning and disinfection of farms, along with water hygiene, showed a positive impact on controlling Salmonella. During the rearing phase, the hygiene program minimised the concentration of Salmonella after 12 weeks, achieving negative results for the rest of the rearing phase.
In the production phase, the effects of the rearing phase combined with actions carried out in breeding houses resulted in an improvement in Salmonella sampling, with only 1 positive sample out of 24 samples taken during the production phase.
At the slaughterhouse, a statistically significant reduction in Salmonella prevalence was observed in the carcasses of chickens from the treatment group, demonstrating that the cumulative reduction in previous phases has a significant impact on prevalence in the fattening phase.
The presence of Salmonella in poultry production requires a holistic approach in which surface and water hygiene is essential to ensure that animals enter an environment free of Salmonella, helping to achieve the best results from the other strategies employed.
* Study research in collaboration with University of Georgia, Athens, United States
* References available on request
