Recovery of Campylobacter from feed using different enrichment media.

Studies were conducted to investigate the recovery of Campylobacter from feed. The impact of feed moisture, water activity, pH, number of background microflora and the use of different antibiotic supplements in Campylobacter enrichment broth (CEB) on Campylobacter recovery were evaluated in five studies. Broiler starter feed was inoculated with 104 -105 cfu of Campylobacter/g and stored at 24 °C and 43% RH. Enrichment culture was conducted on the day of inoculation or 24 h post inoculation and every 48 h of storage thereafter for 14 d. Feed moisture, water activity, pH and level of background microflora were not correlated with Campylobacter recovery. The incubation of feed in CEB with no antibiotic supplement resulted in the number of background microflora increasing to 109 cfu/g and the pH of the media decreasing to pH 4-5 impacting recovery. Addition of certain antimicrobial supplements to CEB reduced background microflora growth and maintained a near neutral pH. Campylobacter was recovered up to 10 days post inoculation when using CEB containing antibiotic supplements compared to 1 day in CEB. These findings suggest that Campylobacter can be recovered from feed and the type of antimicrobial supplement utilized influences recovery by controlling extraneous microbial growth which occurs during enrichment.

Influence of commercial laying hen housing systems on the incidence and identification of Salmonella and Campylobacter.

The housing of laying hens is important for social, industrial, and regulatory aspects. Many studies have compared hen housing systems on the research farm, but few have fully examined commercial housing systems and management strategies. The current study compared hens housed in commercial cage-free aviary, conventional cage, and enriched colony cage systems. Environmental and eggshell pool samples were collected from selected cages/segments of the housing systems throughout the production cycle and monitored for Salmonella and Campylobacter prevalence. At 77 wk of age, 120 hens per housing system were examined for Salmonella and Campylobacter colonization in the: adrenal glands, spleen, ceca, follicles, and upper reproductive tract. All isolates detected from environmental swabs, eggshell pools, and tissues were identified for serotype. Two predominant Salmonella were detected in all samples:S.Braenderup andS.Kentucky.Campylobacter coli and C. jejuni were the only Campylobacter detected in the flocks. Across all housing systems, approximately 7% of hens were colonized with Salmonella, whereas >90% were colonized with Campylobacter Salmonella Braenderup was the isolate most frequently detected in environmental swabs (P<0.0001) and housing system impacted Salmonella spp. shedding (P<0.0001).Campylobacter jejuni was the isolate most frequently found in environmental swabs (P<0.01), while housing system impacted the prevalence of C. coli and jejuniin ceca (P<0.0001). The results of this study provide a greater understanding of the impact of hen housing systems on hen health and product safety. Additionally, producers and academia can utilize the findings to make informed decisions on hen housing and management strategies to enhance hen health and food safety.

Optimizing buffering chemistry to maintain near neutral pH of broiler feed during pre-enrichment for Salmonella.

Salmonella is a human pathogen that can accompany live broilers to the slaughter plant, contaminating fully processed carcasses. Feed is one potential source of Salmonella to growing broilers. Monitoring feed for the presence of Salmonella is part of good agricultural practice. The first step in culturing feed for Salmonella (which may be at low numbers and sub-lethally stressed) is to add it to a pre-enrichment broth which is incubated for 24 h. During the course of pre-enrichment, extraneous bacteria metabolize carbohydrates in some feed and excrete acidic byproducts, causing the pH to drop dramatically. An acidic pre-enrichment pH can injure or kill Salmonella resulting in a failure to detect, even if it is present and available to infect chickens. The objective of this study was to test an array of buffering chemistries to prevent formation of an injurious acidic environment during pre-enrichment of feed in peptone water. Five grams of feed were added to 45 mL of peptone water buffered with carbonate, Tris pH 8, and phosphate buffering ingredients individually and in combination. Feed was subjected to a pre-enrichment at 35°C for 24 h; pH was measured at 0, 18, and 24 h. Standard phosphate buffering ingredients at concentrations up to 4 times the normal formulation were unable to fully prevent acidic conditions. Likewise, carbonate and Tris pH 8 were not fully effective. The combination of phosphate, carbonate, and Tris pH 8 was the most effective buffer tested. It is recommended that a highly buffered pre-enrichment broth be used to examine feed for the presence of Salmonella.

Microbiological impact of three commercial laying hen housing systems.

Hen housing for commercial egg production continues to be a societal and regulatory concern. Controlled studies have examined various aspects of egg safety, but a comprehensive assessment of commercial hen housing systems in the US has not been conducted. The current study is part of a holistic, multidisciplinary comparison of the diverse aspects of commercial conventional cage, enriched colony cage, and cage-free aviary housing systems and focuses on environmental and egg microbiology. Environmental swabs and eggshell pools were collected from all housing systems during 4 production periods. Total aerobes and coliforms were enumerated, and the prevalence of Salmonella and Campylobacter spp. was determined. Environmental aerobic and coliform counts were highest for aviary drag swabs (7.5 and 4.0 log cfu/mL, respectively) and enriched colony cage scratch pad swabs (6.8 and 3.8 log cfu/mL, respectively). Aviary floor and system wire shell pools had the greatest levels of aerobic contamination for all eggshell pools (4.9 and 4.1 log cfu/mL, respectively). Hens from all housing systems were shedding Salmonella spp. (89-100% of manure belt scraper blade swabs). The dry belt litter removal processes for all housing systems appear to affect Campylobacter spp. detection (0-41% of manure belt scraper blade swabs) considering detection of Campylobacter spp. was much higher for other environmental samples. Aviary forage area drag swabs were 100% contaminated with Campylobacter spp., whereas enriched colony cage scratch pads had a 93% positive rate. There were no differences in pathogen detection in the shell pools from the 3 housing systems. Results indicate egg safety is enhanced when hens in alternative housing systems use nest boxes. Additionally, current outcomes indicate the use of scratch pads in hen housing systems needs to be more thoroughly investigated for effects on hen health and egg safety.

The effect of high-level chlorine carcass drench on the recovery of Salmonella and enumeration of bacteria from broiler carcasses.

A study was conducted to determine the bacteriological effect of exposing processed broiler carcasses to a high (10-fold increase) concentration chlorinated drench. During each of 6 replicate trials, eviscerated prechill carcasses were obtained from a commercial processing plant and chlorine-treated carcasses were subjected to a 1-min drench in 500 mL of a 500 mg/kg chlorine solution (sodium hypochlorite). Water-drenched carcasses were treated the same way except water was used in place of chlorinated water drench. Control carcasses were not drenched. All carcasses were then subjected to a whole carcass rinse (WCR) in 450 mL of buffered peptone water, from which 50 mL of the rinsate was removed for enumeration of total aerobic bacteria (APC), Escherichia coli, and total coliforms (TC). The entire carcass was then incubated 24 h at 37°C (whole carcass enrichment, WCE) for recovery of Salmonella. Levels of bacteria recovered from WCR were lower by 0.6 log10 cfu/mL for APC, 0.8 for E. coli, and 0.9 for TC when carcasses were drenched with water compared with undrenched control levels. Similarly, the levels of bacteria recovered from WCR were further lower by 1.0 log10 cfu/mL for APC, 0.5 for E. coli, and 0.5 for TC, when carcasses were drenched with 500 mg/kg of chlorine compared with water. However, there was no significant difference (P > 0.05) in prevalence of Salmonella among the treatments (29% positive for control, 26% positive for water, 38% positive for chlorinated). These results indicate that drenching eviscerated carcasses with water or chlorinated water at 500 mg/kg significantly, but minimally, reduces the numbers of APC, E. coli, and TC bacteria recovered compared with undrenched carcasses. However, neither drenching carcasses with water or high chlorine had an effect on the prevalence of Salmonella that remain with the carcass as determined by WCE. The results of this study confirms the importance of maintaining and replenishing free chlorine for optimal antimicrobial activity, because chlorine at 500 mg/kg was rapidly used within 1 min of exposure to the carcass to <10 mg/kg.

Recovery of Salmonella serovar Enteritidis from inoculated broiler hatching eggs using shell rinse and shell crush sampling methods.

This study compared the recovery of Salmonella from hatching eggs using 3 sampling methods (eggshell rinsing, eggshell crush following a previous rinse, and eggshell crush without previous rinse). Eggshells were drop-inoculated with approximately 10(1), 10(2), or 10(3) cfu/eggshell of Salmonella Enteritidis and allowed to dry at room temperature for 1 or 24 h. For the shell rinse groups, each inoculated egg was rinsed with buffered peptone water. These rinsed eggs were used for the shell crush with previous rinse groups, and each egg was aseptically cracked, the contents discarded, and the eggshell and membranes crushed with buffered peptone water. This same crush procedure was used for the shell crush without previous shell rinse eggs. The recovery of Salmonella 1 h after inoculation for shell rinse sampled eggs was 16% positive at 10(1), 49% at 10(2), and 93% at 10(3) cfu/eggshell challenge. For the shell crush with previous shell rinse, sampled egg recovery was 0% positive at 10(1), 3% at 10(2), and 17% at 10(3) cfu/eggshell. For the shell crush, sampled eggs had recovery of 23% positive at 10(1), 69% at 10(2), and 96% at 10(3) cfu/eggshell challenge. The recovery of Salmonella 24 h after inoculation for the shell rinse eggs was 3% positive at 10(1), 12% at 10(2), and 22% at 10(3) cfu/eggshell challenge; recovery for shell crush with previous shell rinse sampling was 2% positive at 10(1), 8% at 10(2), and 5% at 10(3) cfu/eggshell challenge; and for the shell crush sampling recovery was 2% at 10(1), 32% at 10(2), and 42% at 10(3) cfu/eggshell challenge. Eggshell crush was a more sensitive (∼10 percentage points) sampling method than eggshell rinse at both 1 and 24 h, but both methods were equally optimal when the inoculum was at 10(3) and samples were collected after 1 h. Waiting 24 h after inoculation to sample significantly lowered the recovery for both the shell rinse and shell crush sampling methods by ∼40 percentage points.

Polymerase chain reaction detection of naturally occurring Campylobacter in commercial broiler chicken embryos.

Campylobacter, a foodborne pathogen closely associated with poultry, is recognized as a leading bacterial etiologic agent of human gastroenteritis in the United States. In this investigation, 2 trials were performed where tissues from 7-, 14/15-, and 19-d-old commercial broiler chicken embryos were tested for the presence of Campylobacter using both culturing methodology and PCR. Conventional culturing methods failed to detect Campylobacter from any samples tested during this investigation. Using a set of primers specific for the Campylobacter flagellinA short variable region (flaA SVR), Campylobacter DNA was amplified in 100, 80, and 100% of gastrointestinal tracts from 7-, 15-, and 19-d-old embryos, respectively, in the first trial. Similarly, Campylobacter DNA was detected in 100, 70, and 60% of gastrointestinal tracts of 7-, 14-, and 18-d-old embryos, respectively, in the second trial. In both trials, yolk sac, albumin, and liver/gallbladder samples from 19-d-old embryos all failed to produce amplicons indicative of Campylobacter DNA. Subsequent DNA sequence analyses of the flaA SVR PCR products were consistent with the amplicon arising from Campylobacter. Although a determination of whether the Campylobacter was living or dead within the embryos could not be made, these results demonstrate that Campylobacter-specific DNA is present within the gastrointestinal tract of broiler chicken embryos; however, the means by which it is present and the relative contribution to subsequent Campylobacter contamination of poultry flocks requires further investigation.

Enrichment and Direct Plating for Detection of Campylobacter in Chicken Liver Rinse and Exudate.

ABSTRACT: Foodborne campylobacteriosis has been traced to undercooked chicken liver dishes; thus, it is important to use the best available culture methods when testing for the presence of Campylobacter. We compared two Campylobacter enrichment broths-Bolton formulation and Neogen formulation-in combination with three selective plating media-Campy-Cefex, Campy-Line and RF Campylobacter agars-for detection of Campylobacter from fresh retail chicken livers. In each of three experiments, nine replicate tubs of chicken livers were sampled by drawing exudate and a pooled rinse of five whole liver lobes. Results are reported as number positive and compared by Fisher's exact test. In experiment 1, no combination of enrichment and plating media significantly outperformed another for detection of Campylobacter (P > 0.05); all tubs were found to include Campylobacter in both exudate and liver rinse. In experiment 2, serial dilutions of samples were plated before and after enrichment. Exudate was found to be significantly more likely than rinse to support detection of Campylobacter by direct plating (P < 0.05); most exudate samples included at least 10 CFU Campylobacter per mL. Enrichment improved detection from rinse, but not exudate; all enrichment and plating combinations resulted ≥1,000 CFU/mL from most enriched samples. In experiment 3, samples were diluted before enrichment to determine effect of enrichment on ever lower numbers of Campylobacter. Enrichment did not improve recovery of Campylobacter from exudate or undiluted rinse (P > 0.05). However, when rinse samples were diluted to lower Campylobacter numbers, enrichment improved detection (P < 0.05). Overall, all media combinations tested were equivalent for detection of Campylobacter from chicken livers; sensitivity for detection seemed to be increased by using liver exudate compared with a pooled rinse of liver lobes.

Isolation of Campylobacter from circulating blood of commercial broilers.

Campylobacter spp. are present in organs and tissues of broiler chickens but the dissemination route is unclear. The aim of the current study was to determine Campylobacter prevalence within circulating blood of commercial broilers. Broilers were acquired from 19 flocks originating from three commercial poultry processing companies. Using aseptic blood collection techniques, 5 ml of circulating blood was collected from each bird and the sample analyzed for Campylobacter. The Campylobacter colonization status of each bird was determined by aseptically sampling and analyzing the ceca. Campylobacter was recovered from 58% (11/19) of flocks sampled. From the 248 total birds sampled, 12% and 46% of the birds had Campylobacter in the blood and ceca, respectively. This study documents Campylobacter prevalence in the circulating blood of commercially raised broilers. Campylobacter presence in the circulatory system may indicate the path used by the organism for rapid dissemination to organs and tissues. From a processing viewpoint, Campylobacter presence in circulating blood of market-age broilers may increase the likelihood of cross-contamination between birds during slaughter.

Horizontal transmission of Salmonella and Campylobacter among caged and cage-free laying hens.

In each of five sequential trials, laying hens (56-72 wk of age) were challenged with Salmonella and Campylobacter, and 1 wk postinoculation, the challenged hens (n = 3) were commingled with nonchallenged hens (n = 12) in conventional wire cages, on all-wire slats, or on all-shavings floor housing systems. After 12 days, challenged and nonchallenged hens were euthanatized for sample collection. Ceca were aseptically collected from all hens, and the spleen, liver/gallbladder (LGB), lower (LRT) and upper (URT) reproductive tracts, and ovarian follicles (mature and immature) were collected from only the challenged hens after commingling. Samples were divided equally and cultured separately for Salmonella and Campylobacter. Differences in the horizontal transmission of the challenge Salmonella to nonchallenged hens housed in cages (12%), on slats (15%), and on shavings (14%) were not significantly different (P > 0.05) from the challenged pen-mate hens over the five trials. However, with the inclusion of residual environmental Salmonella, the recovery of Salmonella from nonchallenged hens housed in cages was lowest at 15%, intermediate for hens on slats at 20%, and highest for hens on shavings at 38%. Among challenged hens housed in cages, Salmonella was recovered from only 27% of the cecum and LRT samples. From challenged hens housed on slats, Salmonella was recovered from 38% of the cecum, 12% of the spleen, 19% of the LGB, 44% of the LRT, and 19% of the URT samples. From challenged hens housed on shavings, Salmonella was recovered from 31% of the cecum; 15% of the spleen, LGB, and URT; and 31% of the LRT samples. Horizontal transmission of Campylobacter among nonchallenged pen-mate hens was significantly lower for hens housed in cages at 28% than for hens on shavings at 47%, with hens on slats being intermediate at 36%. For challenged hens housed in cages, Campylobacter was recovered from 27% of the cecum, 13% of the LRT, 7% of the URT, and 17% of the follicle samples. Among the challenged hens housed on slats, Campylobacter was recovered from 44% of the cecum, 6% of the spleen, 19% of the LGB, 12% of the LRT, 6% of the URT, and 14% of the follicle samples. Among challenged hens housed on shavings, Campylobacter was recovered from 46% of the cecum, 8% of the LRT and URT, and 40% of the follicle samples. The overall results of this study indicate that the caged housing system provided the lowest horizontal transmission level of Salmonella and Campylobacter among egg-laying hens.

Colonization of a marker and field strain of Salmonella enteritidis and a marker strain of Salmonella typhimurium in vancomycin-pretreated and nonpretreated laying hens.

This study was conducted to evaluate the influence of a vancomycin pretreatment on the ability of marker (nalidixic-acid resistant) Salmonella Enteritidis (SE(M)), field Salmonella Enteritidis (SE(E)), and marker Salmonella Typhimurium (ST(M)) strains to colonize within the intestinal and reproductive tracts and translocate to other organs of leghorn laying hens. In each of three trials, caged laying hens (76, 26, and 33 wk ofage) were divided into six groups designated to receive SE(M), SE(F), or ST(M), and half were pretreated with vancomycin (n = 11-12 hens). Vancomycin-treated hens received 10 mg vancomycin in saline/kilogram body weight orally for 5 days to inhibit Gram-positive bacteria within the intestines. On Day 6, all hens were concurrently challenged by oral, intravaginal, and intracolonal routes with Salmonella and placed into separate floor chambers by Salmonella strain. Two weeks postinoculation, all hens were euthanatized and the ceca, spleen, liver/gall bladder (LGB), upper (URT), and lower (LRT) reproductive tracts, and ovarian follicles were aseptically collected, and analyzed for Salmonella. Results did not differ for the three hen's ages and were therefore combined. The vancomycin pretreatment also had no significant effect on the colonization ability of SE(M), SE(F) or ST(M), and therefore results were combined within Salmonella strain. The marker strain of Salmonella Enteritidis was recovered from 21% of ceca, 4% of LGB, 9% of LRT, and 17% of the fecal samples. The field strain of Salmonella Enteritidis was recovered from 88% of ceca, 96% of spleen, 92% of LGB, 30% of LRT, 4% of URT, 13% of follicle, and 42% of the fecal samples. The marker strain of Salmonella Typhimurium was recovered from 100% of ceca, 74% of spleen, 91% of LGB, 30% of LRT, 9% of URT, 9% of follicle, and 100% of the fecal samples. Among ceca, spleen, LGB, and fecal samples, SE(F) and ST(M) colonization was significantly greater than SE(M) colonization. Overall prevalence of Salmonella in the reproductive tracts of challenged hens was relatively low, ranging from 4% to 30%.

Comparison between rinse and crush-and-rub sampling for aerobic bacteria recovery from broiler hatching eggs after sanitization.

This study compared surface and deep eggshell aerobic bacteria recovered by the rinse and crush-and-rub sampling methods for commercial hatching eggs after treatment with sanitizers. Eggs were arranged into 5 treatments consisting of no treatment, water, and 3 sanitizers. The sanitizers were H(2)O(2), phenol, and Q(4)B (a compound chemical containing 4 quaternary ammoniums and 1 biguanide moiety). Eggs were sprayed according to treatment and allowed to dry for 1 h before sampling. To collect samples for the eggshell rinse, each egg was massaged in a plastic bag with 20 mL of saline. Eggshells were then aseptically opened and their contents were discarded before being individually crushed into 50-mL centrifuge tubes containing 20 mL of saline. Aerobic bacteria were enumerated on Petrifilm after 48 h of incubation at 37°C. Aerobic bacteria recovered (log(10) cfu/mL) from the eggshell rinse were highest and similar for the no-treatment (4.0) and water (3.7) groups, lower for the phenol (3.2) and H(2)O(2) (3.1) groups, and lowest for the Q(4)B (2.4) group. Aerobic bacteria levels with the crush-and-rub method were similar for the no-treatment (2.5) and water (2.3) groups, lower for the phenol (1.6) group, intermediate for the H(2)O(2) (1.2) group, and lowest for the Q(4)B (0.9) group. The overall correlation between the rinse and crush-and-rub sampling methods for individual egg aerobic bacteria counts was r = 0.71. The correlation within each treatment revealed the following r values: no treatment, 0.55; water, 0.72; H(2)O(2), 0.67; phenol, 0.73; and Q(4)B, 0.38. A second experiment was designed to further examine the lower aerobic bacterial levels recovered by the crush-and-rub method (for previously rinsed eggs) than the levels recovered in the initial eggshell rinse sample. Eggs were either rinsed and then crushed and rubbed, or they were only crushed and rubbed without a prior rinse. Results confirmed a significant decrease (1.5 log(10) cfu/mL) in bacteria levels between the initial rinse (4.4) and the subsequent crush and rub (2.9) for the same eggshell. For the crush-and-rub eggs with no previous rinsing, the bacteria recovery level (3.9) was not significantly different from levels for the rinse method. Therefore, either the rinse or crush-and-rub sampling methods can be used to recover similar levels of eggshell aerobic bacteria.

Effect of stomaching on numbers of bacteria recovered from chicken skin.

Stomaching of skin samples releases only slightly more bacteria than a single rinse. Successive rinses, however, continue to remove almost as many bacteria as the first rinse. One hypothesis to explain this observation is that relatively violent treatment of skin generates smaller pieces of skin, thus increasing the net surface area and effectively sequestering bacteria in a water film on the skin pieces so that numbers of bacteria suspended in the rinsate do not increase. An experiment was conducted to determine whether inoculated marker bacteria are removed from the rinse liquid as skin pieces are stomached and naturally occurring bacteria are released. In each of 4 replications, 5 prechill broiler carcasses were collected from a commercial processing plant. Two 5-g pieces (n = 40) of breast skin were removed from each carcass and placed in a stomacher bag. An inoculum of 30 mL of 0.85% saline solution containing approximately 10(4) of nalidixic acid-resistant Salmonella enterica serovar Typhimurium per milliliter was added to each sample. Skin samples were hand-massaged for 30 s to mix the inoculum, after which a 1-mL aliquot was removed for enumeration of bacteria. A similar sample was taken after 4 min of vigorous stomaching of the skin sample. Bacterial counts recovered from the 30-s hand-massage were 4.3, 2.7, 2.6, and 3.7 log(10) cfu/mL of rinsate for aerobic bacteria, coliforms, Escherichia coli, and Salmonella, respectively. After stomaching, counts were 4.3, 2.9, 2.8, and 3.8, respectively. There was no difference in aerobic plate counts, but mean coliform and E. coli counts were significantly higher (P < 0.05) after stomaching. Numbers of inoculated Salmonella did not decrease. Breaking up the skin into smaller pieces by stomaching did not reduce the number of inoculated bacteria suspended in the rinsate.

Comparison of shell bacteria from unwashed and washed table eggs harvested from caged laying hens and cage-free floor-housed laying hens.

These studies evaluated the bacterial level of unwashed and washed shell eggs from caged and cage-free laying hens. Hy-Line W-36 White and Hy-Line Brown laying hens were housed on all wire slats or all shavings floor systems. On the sampling days for experiments 1, 2, and 3, 20 eggs were collected from each pen for bacterial analyses. Ten of the eggs collected from each pen were washed for 1 min with a commercial egg-washing solution, whereas the remaining 10 eggs were unwashed before sampling the eggshell and shell membranes for aerobic bacteria and coliforms (experiment 1 only). In experiment 1, the aerobic plate counts (APC) of unwashed eggs produced in the shavings, slats, and caged-housing systems were 4.0, 3.6, and 3.1 log(10) cfu/mL of rinsate, respectively. Washing eggs significantly (P < 0.05) reduced APC by 1.6 log(10) cfu/mL and reduced the prevalence of coliforms by 12%. In experiment 2, unwashed eggs produced by hens in triple-deck cages from 57 to 62 wk (previously housed on shavings, slats, and cages) did not differ, with APC ranging from 0.6 to 0.8 log(10) cfu/mL. Washing eggs continued to significantly reduce APC to below 0.2 log(10) cfu/mL. In experiment 3, the APC for unwashed eggs were within 0.4 log below the APC attained for unwashed eggs in experiment 1, although hen density was 28% of that used in experiment 1. Washing eggs further lowered the APC to 0.4 to 0.7 log(10) cfu/mL, a 2.7-log reduction. These results indicate that shell bacterial levels are similar after washing for eggs from hens housed in these caged and cage-free environments. However, housing hens in cages with manure removal belts resulted in lower APC for both unwashed and washed eggs (compared with eggs from hens housed in a room with shavings, slats, and cages).

Comparison of neck skin excision and whole carcass rinse sampling methods for microbiological evaluation of broiler carcasses before and after immersion chilling.

Sampling protocols for detecting Salmonella on poultry differ among various countries. In the United States, the U.S. Department of Agriculture Food Safety and Inspection Service dictates that whole broiler carcasses should be rinsed with 400 ml of 1% buffered peptone water, whereas in the European Union 25-g samples composed of neck skin from three carcasses are evaluated. The purpose of this study was to evaluate a whole carcass rinse (WCR) and a neck skin excision (NS) procedure for Salmonella and Escherichia coli isolation from the same broiler carcass. Carcasses were obtained from three broiler processing plants. The skin around the neck area was aseptically removed and bagged separately from the carcass, and microbiological analysis was performed. The corresponding carcass was bagged and a WCR sample was evaluated. No significant difference (alpha

Comparison of the statistics of Salmonella testing of chilled broiler chicken carcasses by whole-carcass rinse and neck skin excision.

Whether a required Salmonella test series is passed or failed depends not only on the presence of the bacteria but also on the methods for taking samples, the methods for culturing samples, and the statistics associated with the sampling plan. The pass-fail probabilities of the 2-class attribute sampling plans used for testing chilled chicken carcasses in the United States and Europe were compared by calculation and simulation. Testing in the United States uses whole-carcass rinses (WCR), with a maximum number of 12 positives out of 51 carcasses in a test set. Those numbers were chosen so that a plant operating with a Salmonella prevalence of 20%, the national baseline result for broiler chicken carcasses, has an approximately 80% probability of passing a test set. The European Union requires taking neck skin samples of approximately 8.3 g each from 150 carcasses, with the neck skins cultured in pools of 3 and with 7 positives as the maximum passing score for a test set of 50 composite samples. For each of these sampling plans, binomial probabilities were calculated and 100,000 complete sampling sets were simulated using a random number generator in a spreadsheet. Calculations indicated that a 20% positive rate in WCR samples was approximately equivalent to an 11.42% positive rate in composite neck skin samples or a 3.96% positive rate in individual neck skin samples within a pool of 3. With 20% as the prevalence rate, 79.3% of the simulated WCR sets passed with 12 or fewer positive carcasses per set, very near the expected 80% rate. Under simulated European conditions, a Salmonella prevalence of 3.96% in individual neck skin samples yielded a passing rate of 79.1%. The 2 sampling plans thus have roughly equivalent outcomes if WCR samples have a Salmonella-positive rate of 20% and individual neck skin samples have a positive rate of 3.96%. Sampling and culturing methods must also be considered in comparing the different standards for Salmonella.

Efficacy of peroxy acetic acid in reducing Salmonella and Campylobacter spp. populations on chicken breast fillets.

Poultry processors use antimicrobials to reduce the risk of pathogens on poultry and poultry products. The efficacy of selective and nonselective plating media to enumerate injured Salmonella (selective media-brilliant green sulfa agar and Petrifilm Enterobacteriaceae Plate Count; nonselective media-tryptic soy agar and Petrifilm Aerobic Plate Count) and Campylobacter (selective medium-Campy cefex agar and nonselective medium-Brucella agar) populations and the efficacy of peroxy acetic acid (PAA) to reduce Salmonella and Campylobacter populations on chicken breast fillets were evaluated. All plating media for Salmonella and Campylobacter contained nalidixic acid (200 ppm) or gentamycin (200 ppm), respectively. Breast fillets were sprayed or immersed in PAA (500 ppm) for 10 min for evaluation of the plating media. Breast fillets inoculated with a mixed Salmonella and Campylobacter cocktail were sprayed (5 or 10 s) or immersed (4-30 s) in PAA (100, 400, 500, or 1,000 ppm) for evaluation of PAA efficacy. Salmonella populations were higher (P ≤ 0.05) when plated on nonselective media compared with the selective media for the non-PAA treated fillets, although the differences in populations were low (<0.32 log CFU/mL). For both the microorganisms, populations on PAA treated (immersion or spray) fillets were similar when enumerated on nonselective or selective media within each treatment (PAA immersion or spray). Both immersion and spray applications reduced (P ≤ 0.05) the Salmonella and Campylobacter populations compared with the control. Increasing the PAA concentration to 250, 500, and 1,000 ppm resulted in greater reductions (P ≤ 0.05) in Salmonella and Campylobacter populations. Immersion of the inoculated breast fillets in 1,000 ppm PAA solution for 30 s resulted in Salmonella and Campylobacter population reductions of 1.92 and 1.87 log CFU/mL, respectively. Method of antimicrobial application (immersion and spray) did not affect the reductions in Salmonella and Campylobacter populations. Either immersion or spray application can be used to improve microbial safety of chicken breast fillets in a poultry processing plant.

Effects of a dry hydrogen peroxide disinfection system used in an egg cooler on hatchability and chick quality.

A sanitation method that could continually clean and disinfect the air and surfaces in a hatchery could provide a second layer of microbial reduction on top of routine cleaning and disinfection. A gaseous dry hydrogen peroxide (DHP) system has been used in other facilities for this purpose and could have potential for use in chicken hatcheries. Because the DHP is a true gas and can permeate through the entire hatchery space, contact with eggs during storage and incubation could potentially interfere with normal hatching processes. Therefore, the aim of this study was to evaluate the effects of the DHP system on hatching parameters and chick quality. A total of 3,960 hatching eggs were collected from an ∼40-week-old Ross 308 broiler breeder flock and distributed in 2 treatments: treated and nontreated. For the treated group, the egg cooler was cleaned, and 1 DHP generator was placed inside. Two other DHP generators were placed in the common area outside as well. Both areas were treated for 7 D before placement of eggs, and then eggs were collected and placed inside the cooler over a 4-day period. Eggs were then stored for an additional 3 D after the last collection. Dry hydrogen peroxide levels were recorded each day during storage. For the nontreated group, all DHP machines were removed from the cooler and external room, and the egg cooler was cleaned. Eggs were collected in the same way for the control group as the treated group. After storage, eggs were placed into a single stage Natureform incubator. The eggs exposed to DHP showed higher (P < 0.05) hatchability of fertile eggs and lower (P < 0.05) early embryonic dead than eggs from the nontreated group. No other parameters evaluated were different between groups. Based on this work, the DHP treatment of fertile eggs had no detrimental effect on any performance parameter, with potential positive effects seen on hatch of fertile eggs and early embryonic dead embryos.

Research Note: Evaluation of several inoculation procedures for colonization of day-old broiler chicks with Salmonella Heidelberg.

Before starting a study with many birds, it helps to know the method of chick inoculation. The objective was to compare 3 methods of Salmonella challenge (oral gavage [OR], intracloacal inoculation [IC], and seeder bird [SB]). Day-old broiler chicks (n = 100) were inoculated with 106 colony forming units (CFU) per chick of a marker strain of Salmonella Heidelberg (SH) with each route of inoculation. Chicks (n = 25) inoculated by each route were placed in floor pens on fresh pine shavings litter. For the seeder batch, 5 colonized chicks, each orally gavaged with 106 CFUs, were placed with 20 pen mates. Two weeks after inoculation, 10 birds from each pen and the 5 inoculated seeder birds were euthanized, the ceca were aseptically removed and macerated with a rubber mallet and weighed, and 3 times (w/v) buffered peptone was added and stomached for 60 s. Serial dilutions were made and plated onto Brilliant Green Sulfa plates containing 200 ppm nalidixic acid. Plates were incubated along with the stomached ceca for 24 h at 37°C. If no colonies appeared on the plates, an additional plate was streaked from the preenriched bag and incubated for 24 h at 37°C. In addition to all seeder birds being positive, the number of SH-positive birds out of 20 sampled in each group was 13, 17, and 7 for OR, IC, and SB, respectively. The level of SH per g of ceca and cecal contents was log (SE) 3.0 (0.7), 2.0 (0.4), and 2.6 (0.4) for OR, IC, and SB, respectively. After enrichment, the number of colonized birds out of 20 was 18, 20, and 10 for OR, IC, and SB, respectively. In conclusion, this study suggests that IC is the method to use to ensure most of the challenged birds are colonized. However, if you prefer to have a smaller percentage of the birds colonized with higher levels, then OR might be better.

Antimicrobial interventions to reduce Salmonella and Campylobacter populations and improve shelf life of quail carcasses.

Quail (Coturnix japonica) is processed and marketed as fresh meat, with limited shelf life. The objective of this study was to evaluate the efficacy of antimicrobial interventions during slaughter on reducing Salmonella and Campylobacter contamination and to determine the microbiological shelf life of quail during refrigerated (4°C) storage. Three antimicrobials, peracetic acid (400 ppm; PAA), Citrilow (pH 1.2), and Cecure (cetylpyridinium chloride [CPC], 450 ppm), along with a water and no-treatment control were evaluated. Quail carcasses (n = 75) were inoculated with a cocktail of nalidixic acid-resistant Salmonella Typhimurium and gentamicin-resistant Campylobacter coli. After 30 min of attachment time, quail carcasses were submerged in each antimicrobial solution for 20 s with air agitation. Noninoculated quail carcasses (n = 25) were similarly treated, packaged, and stored under refrigeration (4°C). Aerobic plate counts (APC), psychrotroph counts (PC), Enterobacteriaceae counts (ENT), total coliform counts (TCC), and Escherichia coli counts on quail carcasses were determined on 1, 4, 7, and 10 d. Salmonella and Campylobacter populations were determined by plating on Petrifilm APC supplemented with 200-ppm nalidixic acid and Campy Cefex agar supplemented with 200-ppm gentamycin, respectively. No significant reductions in (P > 0.01 log cfu/mL) in APC, PC, ENT, TCC, and E. coli counts were observed on carcasses submerged in water. However, treatments with PAA, Citrilow, and CPC significantly reduced (P ≤ 0.05) Salmonella and Campylobacter coli contamination. Citrilow showed greater (P ≤ 0.05) reduction in Salmonella and Campylobacter population (1.90 and 3.82 log cfu/mL reduction, respectively) to PAA and CPC. Greater (P ≤ 0.05) reductions in APC, PC, ENT, TCC, and E. coli counts (2.22, 1.26, 1.47, 1.52, and 1.59 log cfu/mL, respectively) were obtained with the application of CPC. Application of antimicrobial interventions resulted in a reduction in Campylobacter and Salmonella, APC, PC, and ENT populations after treatments (day 0) and throughout the storage period (day 10). Use of antimicrobial interventions after slaughter can improve the microbiological safety and shelf life of quail.