Comparison of rapid enzyme-linked immunosorbent assay and immunomagnetic separation methods for detection of Escherichia coli O157 in fecal, hide, carcass, and ground beef samples.

Rapid enzyme-linked immunosorbent assays (ELISAs) are approved for detection of Escherichia coil O157 in beef products. However, these kits have also been used in the industry to detect this pathogen on hides or in feces of cattle, although this use has not been validated. The objective of this study was to compare commercially available ELISAs (E. coli Now, Reveal, and VIP) with immunomagnetic separation along with selective media to detect E. coli O157 on hides, in feces, and in medium- and low-level-inoculated ground beef and carcasses (simulated by using briskets) samples. Naturally infected hide and fecal samples were subjected to both the immunomagnetic separation method and ELISAs for the detection of E. coli O157. Additionally, E. coli O157 inoculated and noninoculated ground beef and beef briskets were used to simulate meat and carcass samples. When comparing the detection results from the ELISAs (E. coli Now, Reveal, and VIP) to the immunomagnetic separation method, poor agreement was observed for fecal samples (kappa = 0.10, 0.02, and 0.03 for E. coli Now, Reveal, and VIP, respectively), and fair-to-moderate agreement was observed for hide samples (kappa = 0.30, 0.51, and 0.29 for E. coli Now, Reveal, and VIP, respectively). However, there was near-perfect agreement between the immunomagnetic separation method and ELISAs for ground beef (kappa = 1, 1, and 0.80 for E. coli Now, Reveal, and VIP, respectively) and brisket (kappa = 1, 1, and 1 for E. coli Now, Reveal, and VIP, respectively) samples. Assuming immunomagnetic separation is the best available method, these data suggest that the ELISAs are not useful in detecting E. coli O157 from hide or fecal samples. However, when ELISAs are used on ground beef and beef brisket samples they can be used with a high degree of confidence.

Distribution of Escherichia coli 0157 and Salmonella on hide surfaces, the oral cavity, and in feces of feedlot cattle.

To determine the distribution of pathogens on cattle hides at the feedlot, samples were collected from six hide surface locations (back, flank, hock, neck, perineum, and ventrum), the oral cavity, the rectal-anal junction, and the feces of feedlot cattle and subjected to Escherichia coli 0157 detection via culture methods and to Salmonella detection via PCR. E. coli 0157 was isolated from one or more of the sampling locations from 31 (42.5%) of the 73 animals sampled. Location-specific prevalence of E. coli 0157 was 5% for back samples, 5% for flank samples, 12% for hock samples, 7% for neck samples, 12% for perineum samples, 8% for ventrum samples, 1% for oral cavity samples, 4% for rectal-anal junction swabs, and 23% for fecal grab samples. Salmonella was isolated from one or more of these sample locations from 100% (50 of 50 samples) of all animals sampled. Location-specific prevalence of Salmonella was 76% for back samples, 74% for flank samples, 94% for hock samples, 76% for neck samples, 88% for perineum samples, 86% for ventrum samples, 94% for oral cavity samples, 64% for rectal-anal junction swabs, and 50% for fecal grab samples. The sampling locations that maximized the likelihood of finding E. coli 0157 and Salmonella (84 and 96%, respectively) if the animal was positive at one sampling location or more were the hock, perineum, and fecal grab. These data suggest that the use of multiple sample locations is useful when isolating these pathogens from feedlot cattle. Focusing on one sampling location may underestimate the prevalence.

Ocean wave patterns under hurricane gloria: observation with an airborne synthetic-aperture radar.

Surface imagery of ocean waves under Hurricane Gloria (September 1976) has been obtained with an airborne synthetic-aperture imaging radar. Observations were obtained over most of the area within a radius of 150 kilometers around the center of the eye. These direct observations made it possible to derive the wave patterns in the region around a hurricane eye.

Lunar apennine-hadley region: geological inplications of Earth-based radar and infrared measurements.

Recently completed high-resolution radar maps of the moon contain information on the decimeter-scale structure of the surface. When this information is combined with eclipse thermal-enhancement data and with high-resolution Lunar Orbiter photography, the surface morphology is revealed in some detail. A geological history for certain features and subareas can be developed, which provides one possible framework for the interpretation of the findings from the Apollo 15 landing. Frequency of decimeter-and meter-size blocks in and around lunar craters, given by the remote-sensed data, supports a multilayer structure in the Palus Putredinis mare region, as well as a great age for the bordering Apennine Mountains scarp.

The case for the radar radius of venus.

The Venus radius of 6085 +/- 10 kilometers, deduced from combining observations made with the Venera 4 and Mariner V space probes is incompatible with the value of 6050 +/- kilometers determined from Earth-based radar mesurements.