APPLICATION OF POLYMERASE CHAIN REACTION-OLIGONUCLEOTIDE LIGATION ASSAY FOR THE DETECTION OF SALMONELLAE IN PROCESSED MEAT, POULTRY, FISH, AND PET FOODS

We have tested a rapid and sensitive DNA-based assay for the detection of Salmonella serovars in a number of different processed meat, fish, poultry, and pet food samples. This technique uses an enrichment broth cultivation followed by a Salmonella-specific polymerase chain reaction (PCR) and oligonucleotide ligation assay (OLA) to specifically detect amplified PCR products in an ELISA-based microtiter plate format. The combined cultivation and PCR-OLA techniques were compared with a conventional culture method and with DNA hybridizations of PCR products for the detection of Salmonella bacteria. Eighty-one different processed meat, poultry, and pet food samples were screened for the presence of Salmonella serovars after 24 h and 48 h of enrichment broth cultivation. After 24 h of incubation, one ground turkey sample was positive by both culture and PCR-OLA (100% sensitivity and 100% specificity). After 48 h of incubation, two additional samples (ground beef and a dog food sample) were positive by both culture and PCR-OLA (100% sensitivity and 100% specificity), and three other samples (two ground beef samples and one ground turkey) were positive only by PCR-OLA (96.1% specificity). All positive PCR-OLA results were confirmed in DNA hybridizations with an oligonucleotide specific for the amplified PCR product. When compared to conventional culture, the combined 48 h enrichment and PCR-OLA had a positive predictive value of 50% and a negative predictive value of 100%. We concluded that a combined cultivation and PCR-OLA could be used as a sensitive and specific presumptive screening method for detecting Salmonella serovars in processed meat, fish, poultry, and pet foods.     

Rapid detection of Campylobacter coli,C. jejuni,and Salmonella enterica on poultry carcasses by using PCR-enzyme-linked immunosorbent assay

Contamination of retail poultry by Campylobacter spp. and Salmonella enterica is a significant source of human diarrheal disease. Isolation and identification of these microorganisms require a series of biochemical and serological tests. In this study, Campylobacter ceuE and Salmonella invA genes were used to design probes in PCR-enzyme-linked immunosorbent assay (ELISA), as an alternative to conventional bacteriological methodology, for the rapid detection of Campylobacter jejuni, Campylobacter coli, and S. enterica from poultry samples. With PCR-ELISA (40 cycles), the detection limits for Salmonella and Campylobacter were 2 x 10(2) and 4 x 10(1) CFU/ml, respectively. ELISA increased the sensitivity of the conventional PCR method by 100- to 1,000-fold. DNA was extracted from carcass rinses and tetrathionate enrichments and used in PCR-ELISA for the detection of Campylobacter and S. enterica, respectively. With PCR-ELISA, Salmonella was detected in 20 of 120 (17%) chicken carcass rinses examined, without the inclusion of an enrichment step. Significant correlation was observed between PCR-ELISA and cultural methods (kappa = 0.83; chi-square test, P < 0.001) with only one false negative (1.67%) and four false positives (6.67%) when PCR-ELISA was used to screen 60 tetrathionate enrichment cultures for SALMONELLA: With PCR-ELISA, we observed a positive correlation between the ELISA absorbance (optical density at 405 nm) and the campylobacter cell number in carcass rinse, as determined by standard culture methods. Overall, PCR-ELISA is a rapid and cost-effective approach for the detection and enumeration of Salmonella and Campylobacter bacteria on poultry.     

Influence of octanoic acid addition to medium on some volatile compounds and PR-toxin biosynthesis by Penicillium roqueforti

AIMS: The present study describes the implementation of real-time PCR to tetrathionate broth enrichment step of Salmonella detection in poultry. METHODS AND RESULTS: Real-time PCR with Salmonella invA-specific primers and a standard bacteriological method was applied to detect Salmonella in tetrathionate enrichment cultures of 492 intestinal homogenates and 27 drag swabs from 47 poultry flocks. The number of positive individual samples by real-time PCR and culture method was 65 (12.5%) and 35 (6.8%), respectively. The number of Salmonella-positive flocks was 13 (27.7%) by both methods. PCR detection required 25 min for up to 32 samples. Melting curve analysis revealed the Tm for Salmonella-specific PCR product as 87 +/- 1 degrees C. CONCLUSIONS: Implementation of real-time PCR to tetrathionate broth enrichment step reduces the Salmonella detection time to 18 h and 25 min. Isolation of Salmonella should be carried out with PCR to determine the serovar. SIGNIFICANCE AND IMPACT OF THE STUDY: Real-time PCR is a powerful tool in rapid and accurate Salmonella monitoring in poultry companies, together with standard bacteriology.     

Litter and aerosol sampling of chicken houses for rapid detection of Salmonella typhimurium contamination using gene amplification

Rapid screening of poultry houses for contamination is critical for Salmonella control. Use of air filter sampling has great potential for efficient and reliable monitoring of Salmonella spp., as it could represent an entire poultry house and solve sample-size problems. Two sampling methods (litter and air filter) were compared for detection in four chicken pens inoculated with a S. typhimurium antibiotic resistant strain. Salmonella levels in both litter and air filter samples were determined by PCR amplification and by conventional enrichment. Although amplified DNA was not directly detected, amplified DNA could be detected using a dual probe hybridization sensor. The ratio of the positive samples to total samples determined by gene amplification was much lower than that obtained by conventional enrichments (29/128 versus 102/128 samples). However, the ratio obtained by gene amplification with air filter samples was greater than that with litter samples (26/64 versus 3/64). These results demonstrate that the air filter sampling method is an alternative method of Salmonella detection in poultry house using PCR gene amplification protocol. Journal of Industrial Microbiology & Biotechnology (2000) 24, 379–382. Received 12 August 1999/ Accepted in revised form 17 February 2000     

A MINIATURIZED ENRICHMENT SEROLOGY METHOD FOR RAPID DETECTION of SALMONELLA FROM POULTRY MEAT and REARING FARMS ENVIRONMENT

A miniaturization of the enrichment serology method for the detection of Salmonella was improved in order to make the technique more reliable, cheaper, and faster. the miniaturized method ("Micromethod") was compared to the Sperber and Deibel's method ("Macromethod") and with a classical isolation method; 1062 samples including 700 rearing farms environment samples, 247 poultry meat samples, and 115 nonfat dry milk samples were analyzed. Specificity of both enrichment serology methods was about 92–99.4%. Sensitivity of Micromethod was better than that of the Macromethod for the environmental samples (86.8 and 74.1%, respectively) and the poultry meat samples (87.5 and 77.5%, respectively) but was the same for the nonfat dry milk samples (82.5%). the costs of both methods were respectively 0.43 US $ for the Macromethod and 0.20 US $ for the Micromethod. This "Micromethod" could be proposed for the screening of Salmonella positive batches in the food industries.     

A comparative study of the Gene-Trak Listeria assay, the Listeria-Tek ELISA test and the FDA method for the detection of Listeria species in raw milk

A total of 110 raw milk samples were analysed using the Gene-Trak Listeria assay, unmodified and with four modifications to its enrichment procedure, the Listeria-Tek ELISA test and the FDA method. Thirty-five samples yielded confirmed positive results by at least one of the methods tested. The original Gene-Trak protocol yielded 24 confirmed positive results, significantly higher than the 13 obtained with the Listeria-Tek ELISA test or with the FDA method. The modifications to the Gene-Trak Listeria assay did not significantly increase the detection rate of Listeria spp.     

Evaluation of new culture media for rapid detection and isolation of salmonellae in foods.

Conventional methods for Salmonella detection in foods can require up to 6 and at least 4 days. We have observed that the total analysis time can be reduced to 48 h by using Salmosyst broth as a liquid medium for both preenrichment and selective enrichment and Rambach agar (RA), a new selective plate medium. In samples of artificially contaminated ground beef Salmonella enteritidis was detected at a concentration of 0.4 CFU/g (10 CFU/25 g) by both a conventional method and the new method. Of 519 samples of foods for sale, 38 were Salmonella positive by both methods while 471 were negative. Nine samples which were negative by the conventional method were positive by the Salmosyst-RA method, while one sample positive by the first method was negative by the last. Therefore, the Salmosyst-RA method showed 97.9% sensitivity compared with the 81.2% sensitivity of the conventional method. The new method was also highly specific (98% specificity) in presumptive identification of Salmonella colonies. Furthermore, a 6-h preenrichment in Salmosyst broth has been proved sufficient for the repair of heat-injured Salmonella cells and for subsequent recovery by selective enrichment. In conclusion, the Salmosyst-RA method shows several advantages over both conventional and rapid noncultural methods: (i) only two media are required instead of the five media for conventional methods; (ii) in real time it is comparable to other rapid noncultural methods, which require 30 to 31 h; (iii) it is highly sensitive and specific; and (iv) it allows the isolation of Salmonella strains which can be characterized by appropriate phenotypic and genotypic typing methods for epidemiological investigations.     

Adding a selective enrichment step to the iQ-Check real-time PCR improves the detection of Salmonella in naturally contaminated retail turkey meat products

AIMS: The aim of this study was to compare the real-time iQ-Check Salmonella kit (Bio-Rad) with the immunocapture assay RapidCheck Salmonella method, and a conventional culture method (FSIS, USDA) in detecting Salmonella in naturally contaminated turkey meat products. This study was also designed to determine if a selective enrichment step might improve the real-time detection of Salmonella. METHODS AND RESULTS: Using the culture method, Salmonella was recovered from 49 out of 99 retail turkey meat samples collected. RapidCheck failed to detect 11 Salmonella samples that were positive by the culture method. The iQ-Check real-time PCR also failed to detect three samples that were positive by the culture method. However, when carried out after a selective enrichment step, the iQ-Check real-time PCR detected all 49 Salmonella samples recovered by the culture method. The iQ-Check real-time PCR detected the presence of Salmonella in some samples that were not recovered by the culture method. CONCLUSIONS: Adding a selective enrichment step to the iQ-Check real-time PCR improves the detection of Salmonella in naturally contaminated turkey meat samples. SIGNIFICANCE AND IMPACT OF THE STUDY: The iQ-Check Salmonella real-time PCR can be used as a rapid method to monitor Salmonella in turkey meat, together with conventional culture methodology.     

PCR-ELISAs for the detection of Campylobacter jejuni and Campylobacter coli in poultry samples

Campylobacter species, primarily Campylobacter jejuni and Campylobacter coli, are regarded as a major cause of human gastrointestinal disease, commonly acquired by eating undercooked chicken. We describe a PCR-ELISA for the detection of Campylobacter species and the discrimination of C. jejuni and C. coli in poultry samples. The PCR assay targets the 16S/23S ribosomal RNA intergenic spacer region of Campylobacter species with DNA oligonucleotide probes designed for the specific detection of C. jejuni, C. coli, and Campylobacter species immobilized on Nucleo-Link wells and hybridized to PCR products modified with a 5' biotin moiety. The limit of detection of the PCR-ELISA was 100-300 fg (40-120 bacterial cells) for C. jejuni and C. coli with their respective species-specific oligonucleotide probes and 10 fg (4 bacterial cells) with the Campylobacter genus-specific probe. Testing of poultry samples, which were presumptive positive for Campylobacter following culture on the Malthus V analyzer, with the PCR-ELISA determined Campylobacter to be present in 100% of samples (n = 40) with mixed cultures of C. jejuni/C. coli in 55%. The PCR-ELISA when combined with culture pre-enrichment is able to detect the presence of Campylobacter and definitively identify C. jejuni and C. coli in culture-enriched poultry meat samples.     

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.     

Evaluation of real-time PCR vs automated ELISA and a conventional culture method using a semi-solid medium for detection of Salmonella

AIMS: Evaluation of iQ-Check PCR Salmonella for Salmonella detection in artificially and naturally contaminated food and environmental field samples. METHODS AND RESULTS: Artificially contaminated samples (poultry meat and ground red meat) subjected to cold- and freeze-stress, and 120 naturally contaminated samples (swabs and meat) were tested for Salmonella using the diagnostic semi-solid Salmonella medium (DIASALM) method, the Vidas assay and the iQ-Check PCR assay after 24 h enrichment in buffered peptone water. CONCLUSIONS: Both the iQ-Check PCR and the Vidas assay provide a rapid and user friendly screening method for detection of Salmonella. False negative samples were obtained for the inoculated samples using both the iQ-Check PCR assay and the Vidas method when Salmonella cells were severely stressed. In total 45 of 120 naturally contaminated field samples showed Salmonella positive using the DIASALM method. The agreement percentage with the DIASALM method was respectively 92% for the iQ-Check PCR and 95% for the Vidas method. SIGNIFICANCE AND IMPACT OF THE STUDY: False-negative samples were obtained for the inoculated samples using both the iQ-Check PCR assay and the Vidas method when Salmonella cells were severely stressed, e.g. freezing at -18 degrees C for 7 days. Of the 120 naturally contaminated field samples 45 showed Salmonella positive using the DIASALM method. The agreement percentage with the DIASALM method was 92% for the iQ-Check PCR and 95% for the Vidas method respectively.     

Detection of Salmonella spp. in food by a rapid PCR-hybridization procedure.

A rapid and sensitive PCR-hybridization procedure for detection of Salmonella serovars in food samples was developed. This method is based on three subsequent steps: (1) extraction of nucleic acids from a 2 ml aliquot of the pre-enrichment medium used for the conventional culture method after 6 h of incubation at 37 degrees C; (2) amplification with primers selected from the sequences of invE and invA genes; (3) Southern blot and hybridization with a biotin labeled oligonucleotide probe. The entire procedure requires 30 h. The PCR-hybridization assay was able to detect as little as 50 fg of purified chromosomal DNA of S. typhimurium and 0.2 cfu g-1 of an artificially contaminated food sample. Of 245 food samples analyzed by culture and PCR-hybridization, 20 were positive by both methods and 16 were positive by PCR-hybridization only. None of the 209 PCR-negative samples tested positive by culture. The sensitivity, specificity, alpha and beta error values of the results of the PCR-hybridization procedure, compared with those of culture, were 100, 92.9, 0 and 7.1%, respectively. These results indicate that a short pre-enrichment and PCR-hybridization could be used as a screening test for the detection of Salmonella in food samples.     

Molecular identification of Salmonella isolates from poultry and meat productsin Irbid City,Jordan

The sensitivity and accuracy of molecular diagnosis of Salmonella from meat and poultry products using polymerase chain reaction (PCR) was compared with conventional microbiological methods. A total of 212 samples representing the most frequently used fresh and frozen meat and poultry products (whole, cut, ground, and processed) were collected from different locations within the city of Irbid. DNA was extracted directly from each food sample and amplified using Salmonella-specific primers. Samples were also analysed using conventional microbiological methods for the presence of Salmonella spp. Results showed that Salmonella was detected in 185 samples out of 212 (87%) by PCR technique, while 172 (81%) samples were detected Salmonella positive by conventional microbiological methods. On the other hand, 27 (12.7%) samples were negative by PCR and 40 (18.8%) samples were negative by conventional microbiological methods. PCR assay proved to be an effective method for Salmonella detection in meat and poultry products with high specificity and sensitivity and more importantly a less time-consuming procedure. Using PCR, Salmonella spp. detection could be achieved within 24–36 h compared to 3–8 days for the conventional microbiological methods.     

Evaluation of methods for the identification of Salmonella enterica serotype Typhimurium DT104 from poultry environmental samples

An increase in the prevalence of Salmonella enterica serotype Typhimurium DT104 has been reported worldwide. This study examined the prevalence of this microorganism in poultry environmental samples from commercial layer flocks and pullet environments as well as the sensitivity and specificity of a PCR-based method, and multiple antibiotic resistance profile of Salmonella serogroup B isolates in relation to the serotype and phagetype reference method for the identification of Salmonella Typhimurium DT104. A total of 435 Salmonella isolates were obtained from poultry house environmental samples tested during a 20-month period representing a prevalence of 5.5%. Of these, 313 (72%) isolates were identified as Salmonella serogroup B isolates. These isolates were tested by a PCR-based assay, and for resistance to five antibiotics: ampicillin, chloramphenicol, streptomycin, sulfonamides, and tetracycline (ACSSuT) for the rapid identification of Salmonella Typhimurium DT104. Upon comparing the antibiotic resistance and PCR results with serotype and phage type data, the sensitivity and specificity for the identification of Salmonella Typhimurium DT104 of both methods were found to be 100%, and 99.6%, respectively. Both methods can be completed within 24 h after obtaining an isolate, while serotyping and phagetyping required more than 5 days to complete.     

USE OF THREE RAPID DETECTION SYSTEMS TO EVALUATE THE PREVALENCE AND DISSEMINATION OF SALMONELLA IN A BRAZILIAN POULTRY SLAUGHTERHOUSE

Prevalence and dissemination of Salmonella in a Brazilian poultry slaughterhouse were evaluated by three rapid detection systems (SS/SV^TM, VICAM, OSRT^TM, Unipath/Oxoid, and REVEAL^TM, Neogen), plus the conventional procedure. The carcasses were sampled after bleeding (P1), defeathering (P2), evisceration (P3), washing (P4), chilling (P5) and the packaged end-product (P6). In the first set of carcasses, the Salmonella incidence determined by the conventional method was 38.3% and 22.5% by SS/SV^TM. In the set for evaluation of OSRT^TM, the number of positive samples was the same detected by the cultural procedure (49.0%). In the third set, the positivity by the conventional procedure was 33.3%, and 5.0% by REVEAL^TM. The comparisons of positives in the first and third sets of carcasses were significantly different (P < 0.05). The positivity for Salmonella, in carcasses at P1 to P6, as determined by at least one of the methods, was 47.5%, 47.5%, 32.5%, 30.0%, 30.0% and 37.7%, respectively.     

Molecular Epidemiology of Nontyphoidal Salmonella in Poultry and Poultry Products in India: Implications for Human Health

Human infections with non-typhoidal Salmonella (NTS) serovars are increasingly becoming a threat to human health globally. While all motile Salmonellae have zoonotic potential, Salmonella Enteritidis and Salmonella Typhimurium are most commonly associated with human disease, for which poultry are a major source. Despite the increasing number of human NTS infections, the epidemiology of NTS in poultry in India has not been fully understood. Hence, as a first step, we carried out epidemiological analysis to establish the incidence of NTS in poultry to evaluate the risk to human health. A total of 1215 samples (including poultry meat, tissues, egg and environmental samples) were collected from 154 commercial layer farms from southern India and screened for NTS. Following identification by cultural and biochemical methods, Salmonella isolates were further characterized by multiplex PCR, allele-specific PCR, enterobacterial repetitive intergenic consensus (ERIC) PCR and pulse field gel electrophoresis (PFGE). In the present study, 21/1215 (1.73 %) samples tested positive for NTS. We found 12/392 (3.06 %) of tissue samples, 7/460 (1.52 %) of poultry products, and 2/363 (0.55 %) of environmental samples tested positive for NTS. All the Salmonella isolates were resistant to oxytetracycline, which is routinely used as poultry feed additive. The multiplex PCR results allowed 16/21 isolates to be classified as S. Typhimurium, and five isolates as S. Enteritidis. Of the five S. Enteritidis isolates, four were identified as group D Salmonella by allele-specific PCR. All of the isolates produced different banding patterns in ERIC PCR. Of the thirteen macro restriction profiles (MRPs) obtained by PFGE, MRP 6 was predominant which included 6 (21 %) isolates. In conclusion, the findings of the study revealed higher incidence of contamination of NTS Salmonella in poultry tissue and animal protein sources used for poultry. The results of the study warrants further investigation on different type of animal feed sources, food market chains, processing plants, live bird markets etc., to evaluate the risk factors, transmission and effective control measures of human Salmonella infection from poultry products.     

Application of an automated immunomagnetic separation-enzyme immunoassay for the detection of Salmonella spp during an outbreak associated with a retail premises

AIMS: The application of an automated immunomagnetic separation-enzyme immunoassay (AIMS-EIA) during the investigation of a suspected outbreak of Salmonella food poisoning at a retail premises. METHODS AND RESULTS: Six food samples and 24 environmental swabs were taken from the retail premises and six food handlers' submitted faecal samples during the investigation of the outbreak. Isolation and identification of Salmonella from these samples was performed according to established standard operating procedures and by AIMS-EIA. Twelve of the 18 (67%) Salmonella culture positive samples were AIMS-EIA positive on testing pre-enrichment samples after 24 h, whilst 17 (94%) samples were AIMS-EIA positive following selective enrichment for a further 48 h. One food handler was found to be positive for Salmonella by both culture and AIMS-EIA. All Salmonella isolates were confirmed as Salmonella Enteritidis phagetype 21c. CONCLUSIONS: The AIMS-EIA protocol compliments the conventional culture approach to produce more timely results for the management of the risk to public health without significantly increasing the workload of the laboratory. SIGNIFICANCE AND IMPACT OF THE STUDY: The food production premise investigated in this study was heavily contaminated with Salmonella Enteritidis. Application of the AIMS-EIA was significant in the effective intervention of control measures for the protection of public health.     

Importance of pre-enrichment media for isolation of Salmonella spp. from swine and poultry

The performance of two new (1-day) culture methods, Salmonella Enrichment Broth (SEB) and Revive, and an alternative pre-enrichment broth, designated Universal pre-enrichment broth (UB), was compared to the internationally accepted buffered peptone water (BPW). The study was directed towards detection of Salmonella in 100 faecal samples from porcine and 100 neck-skin samples from poultry. The sensitivity (number of positive cases per method among all the positive cases) of the conventional pre-enrichment in BPW was found to be 0.77 for swine and 0.66 for poultry samples, while a combination of the BPW method with parallel pre-enrichment of the same sample in UB resulted in high sensitivity for swine (0.92) and poultry (0.95) samples. A 2-h pre-enrichment in the non-selective Revive, followed by overnight enrichment in selective broth, resulted in a low sensitivity, particularly for the neck-skin samples (0.16, P=0.001). The SEB method in the porcine samples resulted in a sensitivity (0.71) comparable to the standard method (P=0.31). In conclusion, additional pre-enrichment of samples in UB may substantially increase the culture sensitivity. During routine screening of large numbers of samples, it may be advantageous to use SEB rather than standard culturing.     

DEVELOPMENT OF A PCR ASSAY SUITABLE FOR CAMPYLOBACTER SPP. MASS SCREENING PROGRAMS IN BROILER PRODUCTION

Campylobacter is the most common cause of human acute bacterial gastroenteritis worldwide. In order to comply with the demands of consumers for food free of bacterial pathogens, a mass screening program for Campylobacter in Danish broilers has been carried out based on conventional bacterial culture techniques since 1998. However, using conventional culture methods is time consuming and laborious, and therefore a Polymerase Chain Reaction (PCR) Campylobacter detection assay suitable for mass screening of cloacal swab samples from broilers was developed. By comparing the PCR detection with conventional culture methods, significantly more samples were found positive for Campylobacter with the PCR method. The PCR method is rapid, sensitive and suitable for mass screening for Campylobacter in poultry. Using this PCR method Campylobacter can be detected within 15 h. Notably, the method can be applied to detect Campylobacter directly from chicken feces at the species level.     

Sensitivity, specificity, and predictive values of three Salmonella rapid detection kits using fresh and frozen poultry environmental samples versus those of standard plating

To reduce human exposure to Salmonella spp. in poultry products, broiler chicken flocks have been tested by culture methods. Since the standard techniques may take 3 to 5 days, rapid detection methods have been developed. In this study we tested the performance of three rapid tests originally developed for food samples by using environmental samples obtained from poultry houses. These rapid tests were Reveal, an enzyme-linked immunosorbent assay from Neogen Corp.; BIND, a bacterial ice nucleation detection method from Idetek Corp.; and a filter monitor method from Future Medical Technologies, Inc. For the standard culture, brilliant green with novabiocin and xylose-lysine-tergitol-4 agar were used for presumptive identification, and identities were confirmed by using poly-O antisera. Environmental samples were collected from farms belonging to an integrated poultry company prior to chick placement and 1 week before slaughter. Sensitivities, specificities, and predictive values with 95% confidence intervals were calculated. Statistical differences were determined by using McNemar's chi square test. The sensitivities of the different tests were not stable, varying widely between sample times, and were affected by freezing of the samples. All of the rapid tests had low sensitivities, which led to many false-negative results. All tests were able to detect Salmonella spp. at a concentration of 10 CFU/ml in at least one of four trials. The BIND and Reveal tests were simple to use with multiple samples and reduced laboratory time by up to 1 day. Based on our results, we do not recommend that any of these rapid tests, in their present state of development, be utilized with environmental samples collected with drag swabs.