Decay rates of zoonotic pathogens and viral surrogates in soils amended with biosolids and manures and comparison of qPCR and culture derived rates.

AIMS: The purpose of this study was to establish inactivation decay constants of foodborne pathogens and coliphage in clay and sandy soils for future "downstream" analyses such as quantitative microbial risk analysis and to compare cultivation-dependent and -independent (e.g. qPCR) methods. METHODS AND RESULTS: Salmonella enterica, Campylobacter jejuni, Listeria monocytogenes, Escherichia coli O157:H7, and Clostridium perfringens, were seeded together with MS2 and ØX174 phages, into three waste matrices (Class B biosolids, swine lagoon effluent, cattle manure), and phosphate buffered saline (PBS) as a control, and applied to two soil types (sandy loam, clay loam) using two management practices (incorporated, surface applied). S. enterica and L. monocytogenes inactivation rates were positively affected (e.g. slower rate) by solid wastes, while C. jejuni was quickly inactivated by day 7 regardless of waste type. The use of qPCR provided more conservative inactivation rates, with qPCR-based rates typically twice as slow as cultivation-based. The effect of soil type and management were less apparent as rates were variably affected. For instance, incorporation of waste negatively impacted (e.g. faster rate) inactivation of Salmonella when measured by qPCR, while the opposite was true when measured by cultivation. Inactivation rates were organism∗waste∗soil∗management dependent since the interactions of these main effects significantly affected most combinations. CONCLUSIONS: Class B biosolids and cattle manure most often slowed inactivation when measured by cultivation, but the complex interactions between variables and organism made sweeping conclusions difficult. On the contrary cultivation-independent inactivation rates were negatively affected by solid wastes. Inactivation rates developed by cultivation-dependent and -independent assays needs further scrutiny as interprerations can vary by orders of magnitude depending on the organism∗environment combination. SIGNIFICANCE AND IMPACT OF THE STUDY: This study compares decay rate data based on waste, soil, management and assay type which can be further used in risk assessments.

Risk factors associated with Salmonella status of broiler flocks delivered to grow-out farms.

In a prospective field observational study in the southeastern USA, we sampled gastrointestinal (GI) tracts from chicks of 65 broiler flocks delivered to conventional grow-out farms for rearing. The flocks were hatched at seven broiler hatcheries. The mean within-flock prevalence of Salmonella-positive samples was 6.5% and ranged from 0% to 86.7%. Of the 65 flocks studied, 25 (38.5%) had at least one Salmonella-positive sample. Accounting for confounding variability among the hatcheries and broiler companies, we tested whether the probability of detecting Salmonella in GI tracts of the chicks delivered was associated with certain characteristics of parent breeder flocks; hatchery production volume; hatchery ventilation system; hatchery egg-room conditions; egg incubation, candling, hatching, eggshell and bird separation, and bird-processing procedures; management of hatchery-to-farm transportation; day of week of hatch; weather conditions during transportation; or season of the hatch. Two risk factor models were adopted. The first model indicated that a greater number of parent flocks, manual separation of eggshell and bird, and a greater amount of fluff and feces on tray liners used during hatchery-to-farm transportation at delivery were associated with increased probability of detecting Salmonella in chick GI tracts, whereas a greater number of birds in the delivery vehicle was associated with decreased probability. The second model indicated that broiler flocks hatched on Tuesdays versus either Mondays or Thursdays (with no hatches on Wednesdays, Fridays or week-ends), increased average hatchability of the eggs from the parent flocks, and greater amounts of fluff and feces on the transport tray liners at delivery were all associated with increased probability of detecting Salmonella in chick GI tracts. The results of this study suggest potential management decisions to lessen Salmonella contamination of broilers supplied by commercial hatcheries and areas for further research.

Associations between vaccinations against protozoal and viral infections and Salmonella in broiler flocks.

Reducing the burden of Salmonella in broiler flocks presents a challenge for public health. Worldwide, grow-out broilers are routinely vaccinated to prevent or lessen clinical manifestation of other infections. In this exploratory analysis we tested if details of a routine vaccination programme delivered to conventional grow-out broilers were associated with the burden of Salmonella in the flock as it progressed through its production cycle. None of the flocks studied were vaccinated against Salmonella or received a competitive exclusion product. The flocks were reared on conventional grow-out farms in southeastern USA, and sampled in a prospective field observational study. We observed significant associations between the content and design of a grow-out vaccination programme targeting other infections and the probability of detecting Salmonella in the broiler flock at different time points throughout the production cycle. To the best of the authors' knowledge, this is the first field report of such associations.

Risk factors associated with detection of Salmonella in broiler litter at the time of new flock placement.

In this study, we investigated risk factors associated with the probability to detect Salmonella in samples of litter collected within 2 h prior to new flock placement in 76 grow-out houses on 38 conventional broiler farms located in the US states of Mississippi, Alabama and Texas. We evaluated characteristics of location and layout of the farm; area adjacent to and surrounding the house; house construction; condition and type of equipment in the house; litter management and other production, sanitation, visitation and biosecurity practices; non-broiler animal species on the farm; and weather conditions on the 3 days leading up to flock placement. Logistic regression was used to model the relationships between probability to detect Salmonella in litter and potential risk factors. In the screening process, each risk factor was evaluated as a single fixed effects factor in a multilevel model that accounted for variability among the sampled farms and their production complexes and companies. Of almost 370 risk factors screened, 24 were associated with the probability to detect Salmonella in litter. These were characteristics of the surroundings of the house, house construction and conditions, litter management, length of downtimes between flocks in the house, biosecurity and farm location. After investigation of collinearity between these variables and building of models for important risk factor categories, the list of candidate variables for the final model was refined to eight factors. The final model demonstrated that a higher probability of detecting Salmonella in litter was strongly associated with the use of wood to construct the base of the walls or to cover the inside of the broiler house foundation, and with the use of fresh wood shavings to top-dress or completely replace the litter between flocks.

The change in prevalence of Campylobacter on chicken carcasses during processing: a systematic review.

A systematic review was conducted to evaluate the change in prevalence of Campylobacter on chicken carcasses during processing. A structured literature search of 8 electronic databases using the key words for "Campylobacter," "chicken," and "processing" identified 1,734 unique citations. Abstracts were screened for relevance by 2 independent reviewers. Thirty-two studies described prevalence at more than one stage during processing and were included in this review. Of the studies that described the prevalence of Campylobacter on carcasses before and after specific stages of processing, the chilling stage had the greatest number of studies (9), followed by washing (6), defeathering (4), scalding (2), and evisceration (1). Studies that sampled before and after scalding or chilling, or both, showed that the prevalence of Campylobacter generally decreased immediately after the stage (scalding: 20.0 to 40.0% decrease; chilling: 100.0% decrease to 26.6% increase). The prevalence of Campylobacter increased after defeathering (10.0 to 72.0%) and evisceration (15.0%). The prevalence after washing was inconsistent among studies (23.0% decrease to 13.3% increase). Eleven studies reported the concentration of Campylobacter, as well as, or instead of, the prevalence. Studies that sampled before and after specific stages of processing showed that the concentration of Campylobacter decreased after scalding (minimum decrease of 1.3 cfu/g, maximum decrease of 2.9 cfu/mL), evisceration (0.3 cfu/g), washing (minimum 0.3 cfu/mL, maximum 1.1 cfu/mL), and chilling (minimum 0.2 cfu/g, maximum 1.7 cfu/carcass) and increased after defeathering (minimum 0.4 cfu/g, maximum 2.9 cfu/mL). Available evidence is sparse and suggests more data are needed to understand the magnitude and mechanism by which the prevalence and concentration of Campylobacter changes during processing. This understanding should help researchers and program developers identify the most likely points in processing to implement effective control efforts. For example, if contamination will occur during defeathering and likely during evisceration, critical control points postevisceration are likely to have a greater effect on the end product going to the consumer.

Inter-relationships of Salmonella status of flock and grow-out environment at sequential segments in broiler production and processing.

In this study, we investigated how the likelihoods of Salmonella presence in various samples from broilers and their grow-out environment throughout one production cycle were related. Sixty-four broiler flocks from 10 complexes of two companies in the southern United States were included in the study. Samples from the gastrointestinal tracts of chicks, transport tray pads and litter and drag swabs from the house were collected on the day of placement of each flock. Approximately, 1 week before harvest, whole bird carcass rinses, caecum and crop samples were collected from birds from these same flocks. On the day of harvest, litter and drag swab samples were also taken from the house after the birds were removed. Upon arrival of the flocks at the processing plant, whole carcass rinses, caecum and crop samples were collected. As the flocks were processed, carcass rinses were collected just before the carcasses entered the immersion chill tank and as they exited the chill tank. Logistic regression was used to model the relationships between the likelihood of Salmonella in samples of each type collected at each sampling point and Salmonella frequencies in all the samples taken from the flock and grow-out environment at preceding production stages. The analysis demonstrated that increased likelihood of Salmonella contaminated carcasses entering the immersion chill tank was associated with higher contamination of the exteriors and crops of birds at arrival for processing as well as house environmental samples at the time of harvest and prior to placement. The best predictors of post-chill broiler carcass Salmonella status were the frequencies of Salmonella in the litter on the day of harvest and prior to placement. The immersion chilling appeared to disrupt some of the relationships between the processing plant and pre-harvest samples.

Recovery of Campylobacter from commercial broiler hatchery trayliners.

Previous research has identified Campylobacter as one of the leading causes of foodborne illness. Poultry and poultry products have been identified as a major source of Campylobacter in human infections. Although many risk factors that contribute to Campylobacter levels have been identified, precise identification of the most effective sites for intervention has not been established. Epidemiological studies have identified that Campylobacter in the broiler breeder's reproductive tract, fertile eggs, and 2- to 3-wk-old broilers has the potential to contaminate day-of-hatch chicks. Numerous studies have shown that day-of-hatch broilers are Campylobacter-negative using conventional culture methods. The purpose of the present study was to demonstrate the prevalence of Campylobacter found in day-of-hatch broilers using a peptone water preenrichment followed by conventional Campylobacter culture methods. Using conventional tray liner (hatcheries) culture methods, the isolation distribution of Campylobacter from 8 commercial broiler hatcheries (n = 2,000) was evaluated. A total of 15 tray liners were positive from 3 different hatcheries. Of the 2,000 chick paper pad tray liners sampled, 0.75% were positive for Campylobacter. These data support previous findings indicating the potential for Campylobacter to be spread by vertical transmission. This is the first time that Campylobacter has been recovered from tray liners collected at commercial broiler hatcheries.

Use of secondary enrichment for isolation of Salmonella from naturally contaminated environmental samples.

Since the implementation of Hazard Analysis Critical Control Point (HACCP), the need for on-farm food safety risk assessment and management has greatly increased. In order to provide accurate risk assessments, attention should be focused on better characterization of the Salmonella isolation and identification techniques. In this work, we compared the isolation ability of 4 Salmonella-specific protocols: immunomagnetic separation (DB), tetrathionate (TT) broth, Rappaport-Vassiliadis R10 (RV) broth, and a secondary enrichment (TR) procedure as well as 2 selective solid media (brilliant green agar, BG; and xylose-lysine tergitol 4, XLT4). All 4 methods were compared in litter and drag swab samples that were collected weekly during the broiler grow out period in 7 houses. There were 65/126 (51.6%) pooled litter samples positive and 115/304 (37.8%) drag swab samples positive for Salmonella by at least one method. Of the 65 positive litter samples, DB, RV, and TT isolated 1 (2.7%), 31 (47.7%), and 23 (35.4%) of the samples as positive when using BG agar, respectively. The TR protocol identified 83.1% (54/65) of the positive samples as positive when using BG agar. In the drag swab samples, DB did not identify any samples as positive, whereas TT and RV found 28 (25.7%) and 26 (23.9%) of the 109 samples to be positive when using BG agar, respectively. Again, the TR protocol identified the highest percentage of positive samples (94.5%). An analysis of agreement, kappa, revealed that TT and RV did not always agree on which samples were positive, although the number of samples identified as positive by both were not different. A comparison between the 2 agar plates used, BG and XLT4, showed that they had high agreement when the secondary enrichment protocol was used, but agreement was only moderate to low when the other 3 methods were used.

Comparison of four Salmonella isolation techniques in four different inoculated matrices.

The poultry industry is now operating under increased regulatory pressure following the introduction of the pathogen reduction and hazard analysis critical control point (HACCP) rule in 1996. This new operation scheme has greatly increased the need for on-farm food safety risk management of foodborne bacteria, such as Salmonella. Information needed to make informed food safety risk management decisions must be obtained from accurate risk assessments, which rely on the sensitivity of the isolation techniques used to identify Salmonella in the production environment. Therefore, better characterization of the Salmonella isolation and identification techniques is warranted. One new technique, immunomagnetic separation (IMS), may offer a benefit to the poultry industry, as it has been shown to be efficacious in the isolation of Salmonella from various sample matrices, including some poultry products. In this work, we compared the isolation ability of 4 Salmonella-specific protocols: IMS, tetrathionate (TT) broth, Rappaport-Vassiliadis R10 (RV) broth, and a secondary enrichment (TR) procedure. All 4 methods were compared in 4 different spiked sample matrices: Butterfield's, poultry litter, broiler crops, and carcass rinses. IMS was able to detect Salmonella at 3.66, 2.09, 3.06, and 3.97 log10 cfu/mL in Butterfield's, poultry litter, carcass rinse, and broiler crop matrices, respectively. For the broiler litter and Butterfield's solution, there were no (P > 0.05) differences among the 4 isolation protocols. However, in the carcass rinse and crop samples, there were no differences among the isolation of Salmonella using RV, TR, or TT, but all 3 were (P < or = 0.05) more successful at recovering Salmonella than the IMS method.

Fluorescent marker for the detection of crop and upper gastrointestinal leakage in poultry processing plants.

Previous published research has identified the crop as a source of Salmonella and Campylobacter contamination for broiler carcasses and reported that broiler crops are 86 times more likely to rupture than ceca during commercial processing. Presently, we evaluated leakage of crop and upper gastrointestinal contents from broilers using a fluorescent marker at commercial processing plants. Broilers were orally gavaged with a fluorescent marker paste (corn meal-fluorescein dye-agar) within 30 min of live hang. Carcasses were collected at several points during processing and were examined for upper gastrointestinal leakage using long-wavelength black light. This survey indicated that 67% of the total broiler carcasses were positive for the marker at the rehang station following head and shank removal. Crops were mechanically removed from 61% of the carcasses prior to the cropper, and visual online examination indicated leakage of crop contents following crop removal by the pack puller. Examination of the carcasses prior to the cropper detected the marker in the following regions: neck (50.5% positive), thoracic inlet (69.7% positive), thoracic cavity (35.4% positive), and abdominal cavity (34.3% positive). Immediately prior to chill immersion, 53.2% of the carcasses contained some degree of visually identifiable marker contamination, as follows: neck (41.5% positive), thoracic inlet (45.2% positive), thoracic cavity (26.2% positive), and abdominal cavity (30.2% positive). These results suggest that this fluorescent marker technique may serve as a useful tool for rapid identification of potential changes, which could reduce the incidence of crop rupture and contamination of carcasses at processing.

Cecal volatile fatty acids and broiler chick susceptibility to Salmonella typhimurium colonization as affected by aflatoxins and T-2 toxin.

Four experiments were conducted using day-of-hatch, mixed-sex broiler chicks to evaluate the effects of aflatoxins and T-2 toxin on cecal volatile fatty acids (VFA) and the susceptibility to Salmonella colonization. All chicks in these experiments were challenged orally with 10(4) cfu of Salmonella typhimurium (ST) on Day 3. In Experiments 1 and 2, chicks were fed diets containing 0, 2.5, or 7.5 mg aflatoxins/kg of diet and were allowed to develop their microflora naturally. In Experiment 3, all chicks were orally gavaged on the day of hatch with a competitive exclusion (CE) culture (PREEMPT) and were fed diets containing 0, 2.5, or 7.5 mg T-2 toxin/kg. In Experiment 4, the chicks were fed diets containing 0, 7.5, or 15.0 mg T-2 toxin/kg and one-half of the chicks were orally gavaged on the day of hatch with the CE culture. In Experiments 1 and 2, with the exception of increased total VFA at 5 d in chicks fed the 7.5 mg T-2 aflatoxins/kg diet, there were no treatment effects on cecal propionic acid, total VFA, or incidence or severity of ST colonization. In Experiment 3, the only alteration in concentration of cecal propionic acid or total VFA was a significant reduction in total VFA at 5 d in chicks fed the 2.5 mg T-2 toxin/kg diet. No significant treatment differences were observed for numbers of Salmonella cecal culture-positive chicks or for numbers of ST in the cecal contents. In Experiment 4, with minor exceptions, the chicks treated with the CE culture had higher cecal concentrations of propionic acid and were less susceptible to Salmonella colonization than the non-CE-treated chicks. In the non-CE-treated chicks, T-2 toxin had no effect on any of the parameters, and 85 to 90% of the chicks were Salmonella cecal culture-positive. In the CE-treated chicks, there was a decrease in propionic acid concentration at 3 and 11 d and an increase in susceptibility to Salmonella colonization of the chicks fed the 15.0 mg T-2 toxin/kg diet. These results indicate that cecal concentrations of VFA can be affected by toxins, such as high concentrations of T-2 toxin, and that resistance to Salmonella colonization may be reduced. Further research is necessary to determine the biological significance of these changes.

Effect of lactic acid administration in the drinking water during preslaughter feed withdrawal on Salmonella and Campylobacter contamination of broilers.

The crop is a known source of Salmonella and Campylobacter contamination. We evaluated the use of selected organic acids (0.5% acetic, lactic, or formic) in drinking water during a simulated 8-h pretransport feed withdrawal (FW). Salmonella typhimurium was recovered from 53/100 control crops and from 45/100 of crops from acetic acid-treated broilers. However, treatment with lactic acid (31/100) or formic acid (28/76) caused significant (P < 0.05) reduction in incidence. Reductions of recovered incidence were also associated with reduced numbers of S. typhimurium recovered (e.g., control, log 1.45 cfu/crop; lactic acid, 0.79 cfu/crop). In an additional commercial farm study, broilers were provided 0.44% lactic acid during a 10-h FW (4 h on the farm and 6 h transport) and pre-FW crop, post-FW crop, and pre-chill carcass wash samples were collected for Campylobacter and Salmonella detection. Crop contamination with Salmonella was significantly reduced by lactic acid treatment (6/175) as compared with controls (29/175). Importantly, Salmonella isolation incidence in prechill carcass rinses was significantly reduced by 52.4% with the use of lactic acid (26/175 vs. 55/176). Crop contamination with Campylobacter was significantly reduced by lactic acid treatment (62.3%) as compared with the controls (85.1%). Lactic acid also reduced the incidence of Campylobacter found on pre-chill carcass rinses by 14.7% compared with the controls. These studies suggest that incorporation of lactic acid in the drinking water during pretransport FW may reduce Salmonella and Campylobacter contamination of crops and broiler carcasses at processing.

The diagnostic dilemma of incidentalomas. Working through uncertainty.

The clinical evaluation of incidentally found nodules in the adrenal, thyroid, and pituitary glands is a challenge for physicians, regardless of their level of expertise. Choosing the most direct and cost-effective diagnostic approach and deciding when to treat or not to treat are common dilemmas in clinical practice. This article outlines one diagnostic approach using medical decision-making techniques such as heuristic thinking, critical appraisal of the literature, treatment threshold probability assessment, Bayes' theorem, and discriminant properties of diagnostic tests. These skills are usually discussed in postgraduate training curricula. Nevertheless, they often seem foreign to many clinicians. Evidence suggests that training in these techniques can improve clinical decision making. Use of the skills outlined herein provides a framework to work through the diagnostic uncertainty common in the evaluation of incidentalomas. This approach does not provide perfect answers, as noted in examplar 3 in which two experts argued about the actual pretest probability and treatment thresholds for pituitary incidentalomas. Even if there were no such disagreement, each patient presents unique issues, and there will always be some uncertainty. Nevertheless, this approach provides a starting point from which critical decisions can be made for individual patients.

Effects of long-term feeding of diets containing moniliformin, supplied by Fusarium fujikuroi culture material, and fumonisin, supplied by Fusarium moniliforme culture material, to laying hens.

Beginning at 24 wk of age, control diets or diets containing 50 or 100 mg/kg moniliformin (M), 100 or 200 mg/kg fumonisin B1 (FB1), or a combination of 50 mg M and 100 mg FB1/kg of diet were fed to White Leghorn laying hens for 420 d. The hens were then fed the control diet for an additional 60 d. At the beginning of the experiment, each treatment consisted of four replicates of six hens. Egg production was reduced by approximately 50% by the end of the second 28-d laying period and remained at approximately this level for the 420 d in only the hens fed the diet containing 100 mg M/kg feed. Production returned to control levels or above within 60 d after hens were fed the control diet. Egg weights were reduced by the 100-mg M diet during the first three 28-d laying periods before returning to weights comparable with controls. The hens in this group also had significantly lower body weights than the other treatments. Mortality was minimal except in hens fed the 100 mg M/kg diet and the 100 mg FB1/kg diet, on which approximately 20% of the hens died. The hens were artificially inseminated with semen from males fed control diets, and fertility was not affected by the dietary treatments. Importantly, toxic synergy between M and FB1 was not observed for any of the parameters measured. Results indicate that laying hens may be able to tolerate relatively high concentrations of M and FB1 for long periods of time without adversely affecting health and performance. Interestingly, hens fed the 100-mg M/kg diet were able to recover when returned to control diets. The likelihood of encountering M or FB1 at these concentrations in finished feed is small.

How to design a hospitalist service. An academic health system case study.

Medical centers throughout the country are employing hospitalists--dedicated inpatient specialists--to care for patients during hospitalization in place of their primary care provider. There has been expansive growth of hospitalist programs as the number of practicing hospitalists has doubled in two years from approximately 1,500 to over 3,000. In July 1997, the department of medicine at University Hospitals of Cleveland, the primary teaching affiliate of Case Western Reserve University, created a hospitalist service. This paper will discuss the design of a hospitalist service at a major academic medical center, the factors that were considered during the design stage and financial feasibility.

Survival of Salmonella in the crop contents of market-age broilers during feed withdrawal.

Recent studies have indicated that crop contamination increases during preslaughter feed withdrawal and that contaminated crop contents may serve as an important source of Salmonella entry into poultry processing plants. During the present study, we evaluated the effect of preslaughter feed withdrawal on crop pH and Salmonella crop contamination in broilers from three commercial broiler flocks. The effect of experimental feed withdrawal on crop pH, lactic acid concentration, and Salmonella crop contamination was also evaluated in market-age broilers challenged experimentally with Salmonella typhimurium. Crop pH increased significantly (P < 0.05) from 3.64 +/- 0.25 before feed removal to 5.14 +/- 0.72 after 8 hr of feed withdrawal in broilers from commercial flocks. The incidence of Salmonella crop contamination in the commercial broilers increased (P < 0.05) from 3.3% before feed removal to 12.6% after 8 hr of feed withdrawal. Similarly, crop pH increased (P < 0.05) by a magnitude of approximately 1 unit in broilers after 8 hr of experimental feed withdrawal. The population of S. typhimurium in the crops of the experimentally challenged broilers increased (P < 0.05) by approximately 1 log unit during the 8-hr experimental feed withdrawal. The concentration of lactic acid in the crop of the broilers during experimental feed withdrawal decreased (P < 0.01) from a range of 119-135 mumol/ml before feed removal to a range of 22-32 mumol/ml after 8 hr of feed withdrawal. The results indicated that feed withdrawal resulted in a decrease in lactic acid in the crop, accompanied by an increase in crop pH, and an increase in Salmonella crop contamination.

Presence of Salmonella in the crop and ceca of broiler chickens before and after preslaughter feed withdrawal.

Recent studies have suggested that crop contents may serve as an important source of Salmonella carcass contamination within processing plants. During the present study, we evaluated the effect of preslaughter feed withdrawal on the presence of Salmonella in the crops of broilers from nine commercial broiler flocks reared in individual growout houses. Crops were collected aseptically from 40 randomly selected broilers in each flock before feed removal and at the end of the feed withdrawal period, immediately before capture and transport to the processing plant. Similarly, the ceca were collected before and after feed withdrawal in six of the nine broiler flocks. The presence of Salmonella in the crops and ceca was determined by enrichment culture in tetrathionate broth followed by culture on brilliant green agar. The incidence of Salmonella in crop contents increased significantly (P < 0.05) in five of the nine flocks during feed withdrawal. The total number of Salmonella contaminated crops from all nine flocks increased significantly (P < 0.005) from 7/360 (1.9%) before feed removal to 36/359 (10.0%) at the end of feed withdrawal. The increased incidence of Salmonella in the crop contents was associated with an increased tendency of the broilers to consume contaminated rearing house litter during feed withdrawal. The incidence of Salmonella in the ceca increased nonsignificantly from 14/240 (5.8%) before feed removal to 19/240 (7.9%) at the end of feed withdrawal. The results indicate that the incidence of Salmonella crop contamination may increase as much as fivefold during preslaughter feed withdrawal and represent a critical preharvest control point in reducing Salmonella entry into the processing plant.

Efficacy of various inorganic sorbents to reduce the toxicity of aflatoxin and T-2 toxin in broiler chickens.

Experiments were conducted to determine the efficacy of three inorganic sorbents, S1, S2, and S3, to reduce the toxicity of aflatoxins (AF) and T-2 toxin in male broiler chickens from day of hatch to 21 d of age. The compounds had been reported to bind to AF and T-2 toxin in vitro. S1 and S2 were the same basic compound that had been stored for different lengths of time following activation. In Experiments 1, 2, and 3, the appropriate diets were produced to contain no mycotoxins, the specific adsorbent at 0.5% of diet, AF alone at 5 mg/kg of diet, T-2 alone at 8 mg/kg of diet, AF at 5 mg/kg of diet plus the specific sorbent at 0.5% of diet, or T-2 at 8 mg/kg of diet plus the specific sorbent at 0.5% of diet. The specific sorbents used were: 1) Experiment 1, S1; 2) Experiment 2, S1 and S2; and 3) Experiment 3, S3. In Experiments 1 and 3, S1 and S3, respectively, showed no protection against AF or T-2 toxin as measured by BW gain, when compared to AF alone group. In Experiment 2, S1 showed no protection; however S2 reduced the effects of AF on BW gain by 25% as compared to AF alone diet. The data demonstrate that under the conditions of our experiment: 1) one of the sorbents provided some protection against aflatoxicosis; 2) there was variability in protection against aflatoxicosis between two different samples of the same sorbent that had been stored for different lengths of time following activation; 3) protection by the sorbents against the effects of T-2 toxin was not observed.

Effects of a hydrated sodium calcium aluminosilicate (T-Bind) on mycotoxicosis in young broiler chickens.

Experiments were conducted to determine the ability of a hydrated sodium calcium aluminosilicate (T-Bind) sorbent to reduce the toxicity of aflatoxins (AF) or T-2 toxin in male broiler chickens from day of hatch to 21 d of age. In Experiment 1, the sorbent was added at 0.250 or 0.375% to diets containing AF at 5 or T-2 toxin at 8 mg/kg of diet. When compared with controls, AF reduced BW gain by 27% and T-2 toxin reduced BW gain by 17%. The addition of the sorbent at 0.250 or 0.375%, in the absence of added mycotoxins, did not alter the performance of the chicks. The sorbent reduced the toxic effects of 5 mg AF/kg of diet on BW gain by 43% but did not significantly diminish the toxic effects of 8 mg T-2 toxin/kg of diet. The decreased efficiency of feed utilization and the increased relative organ weights caused by AF were significantly diminished to differing degrees by the sorbent. Oral lesions caused by T-2 toxin were not affected by the sorbent. In Experiment 2, the sorbent was added at 0.80% to a diet containing 8 mg T-2 toxin/kg of diet. The sorbent did not diminish the toxic effects of T-2 toxin when added at 0.80% of the diet. These data demonstrate that this specific sorbent can provide protection against the toxicity of AF, but not T-2 toxin, in young broiler chicks.