Salmonella in dairy operations in the United States: prevalence and antimicrobial drug susceptibility.

Salmonella serotypes are important foodborne pathogens of humans that can be acquired through consumption of contaminated meat and dairy products. Salmonella infection also can be a significant animal health issue. As part of a national study of U.S. dairy operations conducted between March and September 2002, fecal samples were collected from representative cows in 97 dairy herds in 21 states and were cultured to determine the prevalence of Salmonella shedding. Salmonella was recovered from the feces of at least one cow in 30.9% of the herds. Overall, 7.3% of fecal samples were culture positive for Salmonella. The three most frequently recovered serotypes were Salmonella Meleagridis (24.1%), Salmonella Montevideo (11.9%), and Salmonella Typhimurium (9.9%). The susceptibilities of Salmonella isolates recovered were determined using a panel of 16 antimicrobial drugs. Salmonella isolates recovered from dairy cows had relatively little resistance to these antimicrobial agents; 83.0% of the isolates were susceptible to all antimicrobials tested. This study provides updated information on the prevalence and susceptibility patterns of Salmonella in dairy herds and on cow and herd characteristics. These data contribute to our understanding of the ecology of Salmonella in the dairy farm environment.

Profile of raw milk consumers in California.

OBJECTIVES: The authors sought to determine the prevalence of raw milk consumption in California--the largest producer of certified raw milk in the United States--and to describe the demographic and behavioral characteristics of raw milk consumers in that state. METHODS: The authors analyzed responses to questions on the 1994 California Behavioral Risk Factor Surveillance System Survey that asked respondents about whether they drank raw milk, the amount consumed, the reason for drinking raw milk, and where raw milk was most often obtained. RESULTS: Among 3999 survey respondents, 3.2% reported drinking raw milk in the previous year. Raw milk drinkers were more likely than nondrinkers to be younger than age 40, male, and Hispanic and to have less than a high school education. CONCLUSIONS: Raw milk continues to be consumed by some residents of California despite the documented hazards associated with this dietary practice.

Silicone gel breast implant adverse event reports to the Food and Drug Administration, 1984-1995.

OBJECTIVES: To characterize the adverse event reports on silicone gel breast implants (SGBIs), including death reports, submitted to the Food and Drug Administration (FDA) from 1984 through 1995 and to analyze changes in the type and complexity of reports following extensive media coverage of breast implants. METHODS: The authors analyzed mandatory and voluntary reports from the adverse events reporting system for medical devices at the FDA. RESULTS: In 1988, adverse event reports related to SGBIs accounted for 2.4% of the 14,473 mandatory reports entered into the FDA database on medical devices. In 1992, SGBI-related reports accounted for 30.3% of the total 66,476 mandatory reports of adverse events. The most frequently reported adverse event in 1988, before the widespread publicity on breast implants, was implant burst or rupture. In contrast, in 1992 the most frequently reported event was reaction, a term used to describe a range of adverse effects. CONCLUSIONS: The numbers of mandatory and voluntary reports of SGBI-related adverse events increased exponentially, as did the complexity of the reports, following publicity over the lack of safety data on breast implants and a short voluntary moratorium on their sale. A significant proportion of reports lacked information on specific medical symptoms or diagnoses.

Food borne disease summary by food commodity.

Microbial pathogens may be transmitted to humans via food animals and food animal products. A quick reference table is presented to provide easy access to food safety information related to the major food animal product areas. Included in the table are the pathogens, mode of transmission, public health impact, and control and prevention strategies for poultry, beef, dairy products, and pork.

PBBs, PCBs, and dioxins in food animals, their public health implications.

Polybrominated biphenyls (PBBs), polychlorinated biphenyls (PCBs), and dioxins are shown to have toxic potential in food animals and humans through laboratory research and investigation of accidental exposures. This article discusses the ball clay incident, as well as other examples of known accidental exposures to PBBs and PCBs. Background information regarding the mechanism of toxicity and effects in animals and humans is also included.

Importance of prudent antibiotic use on dairy farms in South Carolina: a pilot project on farmers' knowledge, attitudes and practices.

Inappropriate use of antibiotics in humans and animals contributes to decreased antimicrobial susceptibility in bacteria of medical importance. Resistant bacteria being transferred from animals to humans are causing public health concern. In-person interviews were conducted with 20 dairy farmers in rural counties of South Carolina to determine farmers' knowledge and attitudes about prudent antibiotic use among livestock. Four focus groups (n = 22) were also conducted to ascertain farmers' specific information needs about proper antibiotic use. Survey results showed that participants (100%) typically determined a need for antibiotic treatment using symptom assessment and reported following some form of operating procedures regarding administration of antibiotics. Few farmers (32%) had actual written antibiotic protocols. Preferred information sources about antibiotics were veterinarians (100%) and other dairy farmers (50%). Most farmers (86%) were not concerned that overuse of antibiotics in animals could result in antibiotic resistance among farm workers. Qualitative analysis of focus groups revealed significant barriers to following proper antibiotic procedures including limited finances and lack of time. The need for bilingual educational resources for Hispanic/Latino dairy workers was expressed. Desired formats for educational materials were posters, flowcharts, videos, and seminars. Education of South Carolina dairy farmers by veterinarians and public health professionals on the appropriate use of antibiotics in dairy cattle is needed to ensure antibiotic effectiveness in both animals and humans.

Associations between diet and health behavior: results from the 1992 Rhode Island Behavioral Risk Factor Survey.

The 1992 Rhode Island Behavioral Risk Factor Surveillance System was used to assess self-reported health behaviors of consumers of finfish and raw shellfish. We hypothesized that consumers of finfish, foods considered to be healthy, were more likely than nonconsumers of finfish to partake in health-promoting behaviors. Similarly, we postulated that consumers of raw molluscan shellfish, foods linked to an elevated risk of acquiring various illnesses, were more likely than nonconsumers of raw-shellfish to partake in risk-taking behaviors. Finfish eaters were significantly more likely than abstainers to report recent exercise, efforts to lose weight, periodic monitoring of serum cholesterol, and not currently being smokers. Raw shellfish eaters were significantly more likely than abstainers to report recent acute and chronic alcohol consumption. The results suggest that inquiry into dietary patterns may be an avenue for exploring other health behaviors.

The epidemiology of raw milk-associated foodborne disease outbreaks reported in the United States, 1973 through 1992.

OBJECTIVES: This study describes the epidemiology of raw milk-associated outbreaks reported to the Centers for Disease Control and Prevention from 1973 through 1992. METHODS: Surveillance data for each reported raw milk-associated outbreak were reviewed. A national survey was conducted to determine the legal status of intrastate raw milk sales for the period 1973 through 1995. RESULTS: Forty-six raw milk-associated outbreaks were reported during the study period; 40 outbreaks (87%) occurred in states where the intrastate sale of raw milk was legal. CONCLUSIONS: Consumption of raw milk remains a preventable cause of foodborne disease outbreaks.

Prevalence and antimicrobial susceptibility of Salmonella spp. isolates from US cattle in feedlots in 1999 and 2000.

AIMS: Faecal samples from cattle in US feedlots were evaluated for the presence of Salmonella. When Salmonella isolates were recovered the antimicrobial resistance patterns were determined. METHODS AND RESULTS: Faecal samples were collected from pen floors in 73 feedlots in 12 states during the period from October 1999 to September 2000. Pens of cattle selected for sampling were those that had been in the feedlot for the shortest period of time, the longest period of time and a randomly selected pen from the remaining pens. Faecal samples were cultured for Salmonella spp. and all Salmonella isolates were categorized by serotype. The susceptibilities of all isolates were determined using a panel of 17 antimicrobials. Overall, 6.3% (654/10,417) of the samples cultured positive for Salmonella spp. and 22.2% (94/422) of pens and 50.7% (37/73) of feedlots had one or more positive samples. There was little difference in the proportion of positive samples from short-fed (6.1%, 212/3482), random (6.4%, 217/3400) and long-fed (6.4%, 224/3485) pens of cattle. One of two pens of cattle that could not be attributed to a pen type had a single positive sample (2.0%, 1/50). Samples collected during the period of April to June (6.8%, 209/3054) and July to September (11.4%, 286/2500) were more likely to be positive than those collected during October to December (4.0%, 73/1838) and January to March (2.8%, 86/3025). The most common serotypes of Salmonella were dissimilar from those that are typically seen in human illness and cattle illness. The majority of isolates (62.8%, 441/702) were sensitive to all of the antimicrobials tested. Resistance was most frequently observed to tetracycline (35.9%, 252/702) followed by streptomycin (11.1%, 78/702), ampicillin (10.4%, 73/702) and chloramphenicol (10.4%, 73/702). Multiple resistance (resistance to > or =2 antimicrobials) was observed for 11.7% (82/702) of the isolates. CONCLUSIONS: Salmonella was isolated at low frequency from faeces of feedlot cattle and the serotypes were not those commonly associated with human illness. In addition most of the Salmonella isolates were sensitive to all the antimicrobials tested. SIGNIFICANCE AND IMPACT OF THE STUDY: This study contributes to understanding the ecology of Salmonella in cattle feedlots and the prevalence of resistance among potential food-borne pathogens.