Development of research paper writing skills of poultry science undergraduate students studying food microbiology.

Because food and poultry industries are demanding an improvement in written communication skills among graduates, research paper writing should be an integral part of a senior undergraduate class. However, scientific writing assignments are often treated as secondary to developing the technical skills of the students. Scientific research paper writing has been emphasized in an undergraduate course on advanced food microbiology taught in the Poultry Science Department at Texas A& M University (College Station, TX). Students' opinions suggest that research paper writing as part of a senior course in Poultry Science provides students with scientific communication skills and useful training for their career, but more emphasis on reading and understanding scientific literature may be required.

Cultural and Immunological Detection Methods for Salmonella spp. in Animal Feeds - A Review.

Food-borne salmonellosis continues to be a major public health concern, and contamination with Salmonella spp. in pre-harvest animal production is considered a primary contributor to this problem. Animal feeds can easily become contaminated during primary production, feed mixing and processing as well as during feeding. Consequently, monitoring and surveillance of feeds and feed ingredients for Salmonella spp. contamination may be useful or necessary in the prevention and control of this organism. Cultural and immunological detection methods for salmonellae have been used or suggested as possible approaches for use in animal feeds. Cultural methods remain advantageous owing to their ability to detect viable bacterial cells, while immunological methods have the capability of detecting nonculturable bacterial cells. Advancements and improvements in both methodologies offer opportunities for eventual routine use of these detection technologies in animal feed assays.

Polymerase chain reaction detection of foodborne Salmonella spp. in animal feeds.

Foodborne salmonellosis continues to be a public health issue of considerable concern. Animal feed has been a major link in pre-harvest food animal production. Although monitoring systems and control measures are available to limit Salmonella spp. contamination on animal feeds detection methodology is relatively time consuming in the context of time inputs for feed processing and mixing. Current cultural methods of Salmonella spp. detection in feeds require several days for confirmation. This amount of time represents significant problems if control measures are to be effectively implemented in a fashion that keeps feed processing costs low. Molecular methods offer improved sensitivity and potential reduction in assay time. In particular, several commercial polymerase chain reaction (PCR) assays, and combined PCR-hybridization assays have been suggested as possible means to implement more rapid detection of Salmonella spp. extracted from animal feeds. It has now become possible to rapidly detect and confirm the presence of foodborne Salmonella spp. in feed matrices by commercial amplification detection systems. The primary challenges remaining are to develop more reliable recovery and extraction procedures for routine processing of samples from a wide variety of feed matrices and apply molecular techniques for assessing physiological status of Salmonella spp. contaminants in animal feeds.

Comparison of media and a liquid detergent extraction step on bacterial recovery from animal feeds.

The objective of this study was to evaluate the recovery of Tryptic soy agar (TSA) or low nutrient R2 bacterial populations from fresh feeds and animal feeds held in long-term cold storage after extraction with a detergent-based solution combined with repeated centrifugation. Repeated centrifugation after exposure to a detergent-based solution resulted in recoveries generally no more than 10% of the microbial population in the original feed. Feed R2A populations were significantly correlated (P<0.01) with TSA populations enumerated from the feed and feed extracts, as well as R2A populations from feed extracts. Similarly, TSA bacterial populations from feed were significantly correlated with TSA populations from extracts.

Presence of bacteriophages in animal feed as indicators of fecal contamination.

The objectives of this study were to determine if indigenous male specific and somatic bacteriophages could be detected in animal feeds and if isolated phages contained RNA or DNA. Seven fresh feeds, 2 fresh feed ingredients, 7 stored feeds, 2 stored feed ingredients, and 8 samples of poultry diets suspected to contain Salmonella spp. were enriched and spot plated for indigenous phages using Escherichia coli Famp and CN-13 as hosts. Bacteriophage numbers were below detection without enrichment, but both male specific and somatic coliphages were detected in all animal feeds, feed ingredients, and poultry diets after 16 h of enrichment, even after the samples had been stored for 14 months of storage at -20 C. Five out of 9 fresh feeds and 7 out of 8 stored feeds contained RNA somatic phages.

Efficacy of a commercial polymerase chain reaction-based assay for detection of Salmonella spp. in animal feeds.

Salmonellosis is a cyclic problem in the food industry, to which animal feed has been contributory. Current conventional methods of Salmonella spp. detection require 96 h for detection and confirmation. With modern and just-in-time production schedules, a 96-h hold represents a significant expense in storage and decontamination. The commercially available assay, 'BAX for Screening/Salmonella' (BAX), is based on the principle of the polymerase chain reaction and may represent a significant decrease in assay time. Seven fresh feed formulations, two fresh feed ingredients, seven stored feeds and two stored feed ingredients were artificially contaminated with a primary poultry isolate of Salmonella typhimurium and analysed by conventional and BAX methodology. The results of BAX agreed with conventional plating results for 16 of 18 samples spiked with 1200 cfu 10 g(-1) of feed and 13 of 18 samples spiked with 40 cfu 10 g(-1) of feed. Indigenous Salmonella spp. were detected in five of eight samples of poultry diets by conventional methods. With BAX, Salmonella spp. could not be detected in any of the samples after only 7 h of enrichment but could be detected in two dietary samples after 13 h of enrichment and four dietary samples after 24 h of enrichment. Specific sequences of salmonella DNA that were extracted from poultry diets could be detected with BAX.

Assessment of demand for a job placement service for the Poultry Science Association.

A placement service for the membership of the Poultry Science Association (PSA) is a possible future consideration. This service should provide a formal national platform that could aid membership and their employers in position services. A survey was conducted with the objective of determining the interest of the membership in such a placement service and the maximum expense that members would be willing to pay for the service. Ten questions in an undisguised questionnaire format, covering demographic, historical, and interest points was devised with survey questions designed for a forced response on most of the questions. A total of 2,050 surveys was mailed to PSA members in the US, including 1,850 regular members and 200 student members; 518 responded to the survey. A majority of all age groups favored the construction of a placement service, but the respondents' willingness to use the service depended upon age, education, and work experience and whether or not they believed a placement service was needed. Sources of information used in finding a position varied with age; trade journals and publications were the most frequent sources for the responses. It appears that the membership likes the idea of a placement service, is willing to pay something for it, and would use it if it were available.

Consumer poultry meat handling and safety education in three Texas cities.

Shifting demographics, increased poultry consumption and a general ignorance concerning food safety measures provide the potential for increased foodborne illness. In order to determine where food safety educational efforts would be most effective and the needed content of the messages, a survey addressing poultry preparation, storage and thawing methods, and sources of food safety education was constructed and distributed in supermarkets in three Texas urban centers. Between 60 and 67% of consumers prepared poultry once or twice per week. A majority of Hispanics (57%), minors (79%) and uneducated (55%) respondents thaw poultry outside of the refrigerator, either on a counter, in a microwave, or in a sink of water. A majority of Caucasians receive food safety information from either magazines (52%) or television (60%), whereas minors receive education mainly from the educational system (57%) or family (71%). Through increased education in these areas, good food safety habits may be increased in those target groups, especially the next generation of consumers.

Diet and carcinogen alter the fecal microbial populations of rats.

An analysis of viable bacterial populations enumerated on carbohydrate selective media was used to simulate the colonic environment in vitro and determine if differential media could detect significant microbial shifts due to dietary fiber source, dietary fat source, and carcinogen. Male Sprague-Dawley rats were provided with either pectin or cellulose as a fiber source, either corn or fish oil as a source of fatty acids, and injected with either azoxymethane (AOM), a gastrointestinal carcinogen, or saline in a 2 x 2 x 2 factorial design. At 6 and 10 mo of age, fresh feces were collected, homogenized in anaerobic buffer and anaerobically plated onto differential media. Diets containing pectin supported more anaerobes at 6 mo of age (P < 0.01) than diets containing cellulose. Rats injected with AOM and consuming either pectin or corn oil supported more anaerobes at 10 mo of age (P < 0.05) than rats injected with saline and consuming the same diets. Rats consuming cellulose and receiving AOM but not expressing tumors possessed larger anaerobic populations at 10 mo of age (P < 0.05) than rats consuming cellulose, injected with AOM and expressing tumors. These effects show that gastrointestinal bacterial populations, as measured by carbohydrate specific media, respond to dietary changes such as dietary fiber source, and thus may play a key role in the etiology of colon cancer.

Fermentation and growth response of a primary poultry isolate of Salmonella typhimurium grown under strict anaerobic conditions in continuous culture and amino acid-limited batch culture.

Salmonella typhimurium is a significant hazard to consumer health that is carried asymptomatically in poultry gastrointestinal tracts. Nurmi cultures may prevent Salmonella colonization in young chicks, but the mechanism of competitive exclusion is unclear. Modeling Salmonella's metabolism in pure culture may allow for greater definition in choosing strains for Nurmi cultures. The growth rates and affinity constants of S. typhimurium growing in amino acid-limited conditions were determined in batch culture and compared to primary poultry isolates of cecal strains. Serine and NH4Cl were the best N sources for growth of all organisms tested in this study. The fermentation response of S. typhimurium was also monitored in continuous culture at a slow dilution rate of 0.021 h-1. S. typhimurium was found to adapt to VL media, with trends in protein disappearance, Yglucose, and Yprotein. This may show that amino acid or protein concentrations may be an integral component of the initial establishment of S. typhimurium in the cecum.