Harold M. Barnhart

Prevalence of Salmonella enteritidis and other serovars in ovaries of layer hens at time of slaughter

Ovaries aseptically collected from commercial layer hens at time of slaughter were assayed for Salmonella as an indication of systemic infection of birds within a flock. Birds were randomly selected at the time of slaughter from 42 flocks from seven southeastern states and Pennsylvania. Ovaries were pooled, four per pool, mascerated, and Salmonella , isolates were recovered by conventional methods. Thirty-two of 42 flocks (76.2%) were positive at >10% infection rate based on sampling methods. Fifteen different serovars were detected in flocks. Salmonella heidelberg was the predominant serovar, representing 56.5% of the salmonellae detected. However, S. agona , S. oranienburg , S. mbandaka , S. kentucky , S. montevideo , S. london , S. typhimurium , S. infantis , S. schwarzenqrund , S. ohio , S. cerro , S. anatum , and Salmonella untypeable were also found. S. enteritidis , phage type 23 was recovered from only one (2.4%) of the flocks. Single and multiple serovar infections were found with up to five serovars recovered from a single flock. Twenty-one positive flocks (50%) were positive with a single Salmonella serovar; of these S. heidelberg represented 76.2%. An overall mean of 26.6% of the pooled ovary samples within each infected flock was positive for salmonellae, with an overall range of 0-100%. The significance of Salmonella serovars other than S. enteritidis found at the levels reported has yet to be determined.

Detection of Campylobacter jejuni Strains in the Water Lines of a Commercial Broiler House and Their Relationship to the Strains That Colonized the Chickens

SUMMARY. Campylobacter jejuni is frequently present in the intestinal tract of commercial broiler chickens, and their drinking water has been proposed to be an initial source of bacteria for newly hatched chicks. We studied three sequential commercial broiler flocks raised in a house from which we had cultured C. jejuni from the nipple waters prior to placement of the first flock. Campylobacter cells were detected by immunofluorescence in the biofilm of the drinking nipples during the weeks when the flock was colonized with C. jejuni but not during weeks when the birds were negative. Campylobacter jejuni was isolated from the drinking water during the growth of the first flock and was present in the birds from all three flocks. Randomly amplified polymorphic DNA (RAPD)–polymerase chain reaction (PCR) typing with primer OPA11 indicated that seven distinct strains were present within the broiler house. One strain found in drinking water was similar to a strain found in birds in the second flock; however, RAPD-PCR with primer HLW85 showed that the strains were not identical. These results suggest that although the watering system is a potential source of C. jejuni in broiler flocks, the waterborne strain in this study was not detected in the birds.

Calcium, phosphorus, and magnesium contents of human milk during early lactation.

Summary Early milk samples from 102 American mothers were examined for Ca, P, and Mg contents in relation to stage of lactation, intake of prenatal mineral supplements, maternal age, parity, and previous history of lactation. A total of 415 samples were collected at three stages of lactation: early transitional (4–7 days postpartum); transitional (10–14 days postpartum); and mature (30–45 days postpartum). No diurnal variations in element concentrations were observed in representative samples of late evening (PM) and early morning (AM) feedings collected during the transitional and mature stages. The mean concentrations for the major elements were highest in early transitional milk and in some cases decreased significantly (p < 0.05) as lactation progressed. Ca, P, and Mg contents (means ± SEM) were 26.3 ± 0.6, 14.6 ± 0.4, 5.3 ± 0.1 mg/100 g in early transitional milk and 26.2 ± 0.5, 13.3 ± 0.3, and 5.0 ± 0.1 in mature milk, respectively. Increasing uniformity in the elemental content of milk was noted among the mothers as lactation became established. No significant relationship was found between intake of dietary supplements containing Ca and Mg and levels of these elements in milk. Also, no significant correlations were found between maternal age, parity, or previous history of lactation and the elemental content of milk. From these data, it was estimated that fully breast-fed infants would receive approximately 33, 18, and 6.5 mg/kg/day of Ca, P, and Mg, respectively, during the neonatal period.

Fate of Selected Bacterial Pathogens and Indicators in Fractionated Poultry Litter During Storage

Abstract A study of broiler litter re-utilization potential was conducted with the goal of determining if storage of litter significantly reduced potential pathogens to levels safe for re-utilization. Litter from four broiler houses was separated into a fine fraction for fertilizer use and a coarse fraction for use as a supplement to wood shavings in growing subsequent flocks of birds. Fractions and whole litter were stored in indoor piles for four months with periodic analysis for culturable pathogenic and indicator bacteria. Significant reductions in microbial concentrations occurred in a majority of samples tested during four months of storage (in most cases to below detection limits of approximately 30 CFU/g dry weight). Poultry feed was found to be one possible source of litter contamination.

IgA, IgG, IgM and Lactoferrin Contents of Human Milk During Early Lactation and the Effect of Processing and Storage

The total IgA, IgG, IgM and lactoferrin concentrations in human milk from 89 donors were studied at three lactational stages: early transitional (3 to 8 d postpartum), transitional (10 to 14 d postpartum) and mature (30 to 47 d postpartum). The effects of processing and storage on these components in composite samples of mature human milk were determined. There were no significant diurnal variations in any of the four protective factors at either the transitional or mature stages. Concentrations of total IgA, IgM and lactoferrin decreased significantly as time postpartum increased, whereas the IgG content showed no significant changes. The total IgA, IgM and lactoferrin levels were significantly decreased by all heat treatments (62.5°C for 30 min, 72°C for 15 s, 88°C for 5 s, and 100°C for 5 min). Heating at 62.5°C for 30 min did not affect the IgG content; however, the other heat treatments significantly reduced IgG concentration. At the times and temperatures selected for this study, the two lower temperature treatments were less detrimental to the protective factors than the higher temperature treatments.

Recovery of Aeromonas hydrophila from carcasses and processing water in a broiler processing operation

Aeromonas hydrophila , a potential pathogen associated with cases of human diarrhea, was enumerated using a rinse method on broiler carcasses and in processing water at selected locations in a commercial processing plant. A. hydrophila was detected on 98% of all carcasses tested, and 92% of all chill water samples; scald and rinse water samples were negative for this organism. Mean numbers on carcasses ranged for 28 CFU/ml of rinse fluid, detected immediately after the chiller, to 580 CFU/ml of rinse fluid at the post-evisceration stage. Water chilling and washing resulted in a significant reduction in A. hydrophila numbers on carcasses, while refrigerated storage (48 h) resulted in a significant increase. Data suggest that isolates recovered from carcasses may likely have been of intestinal origin and that the evisceration step was a probable cause of contamination. A. hydrophila levels on carcasses and processing waters showed no correlation to other bacteriological parameters which might be used in a process evaluation program.

Folate content of human milk during early lactational stages

Abstract In order to expand and update the nutritional information of human milk, the biotin content was determined in early transitional (three to eight days postpartum), transitional (10 to 14 days postpartum), and mature (30 to 47 days postpartum) human milk from 84 donors. The women ranged in age from 16 to 38 years. The biotin level increased significantly (P

Stabilization of poultry processing by-products and poultry carcasses through direct chemical acidification

Abstract Laboratory and field experiments were conducted to test the feasibility of using chemical acidification for stabilizing poultry-processing offal and blood and poultry carcasses. Acidification of the ground poultry materials with 2% (w/w) of 90% formic acid was the most economical method for preventing putrefactive changes and did not adversely affect crude protein and fat content. The acid-preserved offal and carcasses were stable semi-liquid/solid products with pHs of 4.0–4.2. When stored for 28 days at 30°C, the acidified offal and carcass products had approximately 67 and 62% moisture, 12 and 14% protein, 17 and 15% fat, and 0.16 and 0.23% ammonia, respectively. Several problems were identified, however, when the acid-treated offal was heat-processed to produce a dry feed meal.

Thermal Destruction of Escherichia coli and Klebsiella pneumoniae in Human Milk

A continuous flow high-temperature short-time pasteurization system was used to determine kinetic parameters (D- and z-values) for thermal destruction of the bacterial pathogens, Escherichia coli and Klebsiella pneumoniae , in mature human milk. D-and z-alues of each bacterium were determined from data on survivors enumerated on both selective media, Violet Red Bile agar or MacConkeys, and on a non-selective medium, nutrient agar (NA). For E. coli , D-values were determined at 58, 60, 62 and 64°C. The predicted value of D at 60°C is 31.5 s. The z-value for E. coli is 3.2°C. D-values for K. pneumoniae were determined at 52, 56 and 58°C. Based on these data the predicted value of D at 60°C is 1.3 s. The z-value for K. pneumoniae , is 2.8°C. For both E. coli and K. pneumoniae , counts on NA tend to be higher than on selective media. This is undoubtedly due to the inhibitory nature of the selective media. This also suggests that some degree of thermal injury may occur for each organism.

Cytotoxicity and Antibiotic Resistance Profiles of Aeromonas hydrophila Isolates From a Broiler Processing Operation

The cytotoxicity and antibiotic resistance profiles of Aeromonas hydrophila isolates recovered from broiler carcasses and chill water samples taken from a Georgia processing plant were determined. Carcasses were sampled at pre- and post-evisceration locations, immediately after immersion chilling, and after being boxed, iced and refrigerated for 48 h. Grab samples of chill water were randomly selected for A. hydrophila recovery. Resistance of isolates to nine antibiotics was determined with the Bauer disc diffusion method (i.e., to ampicillin, cephalothin, streptomycin, kanamycin, chloramphenicol, naladixic acid, tetracycline, neomycin, and gentamicin). Multiple antibiotic resistance occurred in 46.2% of 119 isolates. The majority of the multiple antibiotic-resistant isolates (76.4%) were resistant only to ampicillin and cephalothin. The remaining multiple antibiotic-resistant isolates (23.6%) were resistant to various combinations of 2, 3, or 4 antibiotics, most of which were recovered from carcasses immediately after evisceration. Cytotoxin activity was detected in 63.8% of all isolates using the Y-1 mouse adrenal tumor cell line. Cytotoxin positive isolates were recovered from all sampling locations including chill water. The highest cytotoxicity titers were shown among isolates recovered from carcasses immediately after evisceration. These data suggest bird fecal contamination as an important source of A. hydrophila in broilers and broiler processing plants rather than environmental contamination.