Reducing Salmonella contamination in poultry is of major importance to prevent the introduction of this microorganism into the food chain. Salmonellae may spread during storage time (shelf life) whenever pre-harvest control fails or post-harvest contamination occurs. Therefore, preventive measures should also be used in the post-harvest level of poultry production in order to control salmonellae. Chicken skin samples were experimentally contaminated by immersing whole legs (thighs and drumsticks) in a suspension containing 10(6) colony forming units per milliliter (CFU/mL) of Salmonella Enteritidis phage type 4 (SE PT4) at the slaughter day. One day later, samples from one group were immersed in a suspension pool containing 10(9) CFU/mL of each of three wild salmonella-lytic bacteriophages previously isolated from feces of free-range chickens. Salmonella counting was performed at three-day intervals in the chicken legs stored at 5°C and showed a significant reduction (P<0.05) of SE PT4 in bacteriophage-treated cuts on days 3, 6 and 9 post-treatment. These findings suggest that the use of bacteriophages may reduce SE PT4 in chicken skin. Further studies are encouraged and might demonstrate the potential of this approach as an efficient and safe technique to be routinelly used for Salmonella control in chicken products.

Occurrence of food poisoning related to Salmonella-contaminated eggs and chicken meat has been frequent in humans. Salmonella Enteritidis (SE) and Salmonella Typhimurium (ST) are included among the most important paratyphoid salmonellae associated with chicken meat and eggs. Elimination of Salmonella at the pre-harvest stage can play a significant role in preventing the introduction of this pathogen into the food chain and consequently in the reduction of food poisoning in humans. Bactericidal bacteriophages may provide a natural, nontoxic, feasible and non-expensive component of the multi-factorial approach for a pre-harvest control of Salmonella in poultry. Five bacteriophages lytic for SE PT4 and ST were obtained from 107 samples of feces of free-range layers in Brazil. All bacteriophages were characterized in vitro and in vivo, showing head and tail morphology and dsDNA as nucleic acids. Results of "in vivo" studies suggested that bacteriophages do not remain in Salmonella-free birds longer than one day, whereas they multiply in Salmonella-infected birds for longer periods. Besides, selection for phage-resistant SE PT4 did not seem to occur in the short term. Isolated bacteriophages will be investigated for their potential for pre-harvest biocontrol of SE PT4 in poultry.

There is a need for a better understanding of the epidemiology of Mycoplasma synoviae (MS) infection in broiler breeders in Brazil. Many features of the infection remain unrecognizable, because there are no clinical signs of the disease. A detailed testing was performed at each 6 to 8 weeks in three MS-free flocks introduced in farms with endemic MS infection for a follow-up epidemiological study. Every flock was monitored by polymerase chain reaction (PCR), by serum plate agglutination (SPA) and hemagglutination inhibition (HI) for serology studies, and isolation of mycoplasmas from tracheal swabs. PCR was found to be the most sensitive test, detecting early MS infection. Serology was positive in less than 50% of the sera and MS was isolated only between 27 and 28 weeks of age and in a maximum of 60% positive hens. A similar profile was seen for MS infection in all three flocks. Infection started at brooding, whereas laboratory detection of the assymptomatic infection was more probable in the weeks of increasing egg production. This predictable profile during rearing may be very useful for the optimization of monitoring MS infection in broiler breeder flocks.