The influence of fructooligosaccharide (FOS) on the ability of Salmonella typhimurium to grow and colonize the gut of chickens was investigated. In vitro studies showed that Salmonella did not grow when FOS was the sole carbon source. When FOS was fed to chicks at the .375% level, little influence on Salmonella colonization was observed. At the .75% level, 12% fewer FOS-fed birds were colonized with Salmonella compared with control birds. When chicks given a partially protective competitive exclusion (CE) culture were fed diets supplemented with .75% FOS, only 4 of 21 (19%) chickens challenged with 10(9) Salmonella cells on Day 7 became colonized as compared with 14 of 23 (61%) chickens given CE alone. When chickens were stressed by feed and water deprivation on Day 13 and challenged with 10(9) Salmonella on Day 14, 33 of 36 (92%) chickens fed a control diet were colonized compared with only 9 of 36 (25%) chickens fed a .75% FOS diet. Chickens treated with FOS had a fourfold reduction in the level of Salmonella present in the ceca. Feeding FOS in the diet of chickens may lead to a shift in the intestinal gut microflora, and under some circumstances may result in reduced susceptibility to Salmonella colonization.

A study was conducted of 32 broiler flocks on eight different farms, belonging to four major U.S. producers. The farms were studied over I complete calendar year. Overall, 28 (87.5%) of the flocks became Campylobacter positive, and only four (12.5%) remained negative throughout the 6- to 8-week rearing period. In the majority of flocks, sampled every 2 weeks throughout production, Campylobacter-positive fecal and cecal samples were not detected until 4 to 8 weeks of age. In only six of the flocks were environmental samples found to be positive before shedding of Campylobacter was detected in the birds. Even in some of the Campylobacter-negative flocks, contamination of the rearing environment was positive for Campylobacter but did not result in the birds subsequently excreting the organism. These findings are discussed in relation to U.S. husbandry practices and present uncertainty about sources of Campylobacter infection for poultry flocks. Birds were often transported to the processing plant in coops that were already contaminated with Campylobacter, and the organisms were sometimes found in samples of scald water and chill water. After chilling, the proportions of Campylobacter-positive carcasses from different producers ranged from 21.0 to 40.9%, which is lower than in other studies, and possible reasons are considered.

Colonization of the ceca and contamination on carcasses of chickens by Campylobacter spp. was investigated. Samples were taken on the farm and after transport and holding. In the first set of experiments, 20 chickens, obtained from each of 10 broiler farms, were collected from houses containing 6- to 7-wk-old birds. Half of the birds were slaughtered at the farm; the other half were transported (10 birds per chicken coop) to a holding facility and killed within 16 to 18 h. The levels of Campylobacter spp. on the carcass and in the ceca were assessed. Ceca from birds in 9 of the 10 farms sampled were positive for Campylobacter spp. Colonization levels ranged from 10(4.11) to 10(7.28) cfu Campylobacter spp./g cecal matter, except on one farm, where the organism was not isolated. The mean count on the farm was 10(5.44) cfu Campylobacter spp./g cecal material, and after transport the mean was 10(6.15) cfu/g. Significant increases (P = .0085) in levels of Campylobacter spp. on the chicken carcasses occurred after transport. Levels of Campylobacter spp. enumerated from unprocessed chicken carcasses after transport averaged 10(7.11) per carcass, up from an average of 10(3.66) cfu per carcass of the farm. To further verify this observation, field trials were conducted to assess levels on carcasses before and after commercial transport. Employing five farms and 200 6-wk-old chickens, the above observations were confirmed: prior to transport 12.1% of the chickens harbored an average of 10(2.71) cfu per carcass, but after transport 56.0% of the chicken exteriors harbored an average of 10(5.15) cfu per carcass. The results of this study indicate that transport and holding prior to processing contributes to the Campylobacter spp. of > 10(4) cfu normally found on processed poultry carcasses.