Salmonella enterica isolates from pasture‐raised poultry exhibit antimicrobial resistance and class I integrons

Aims: While considerable foodborne pathogen research has been conducted on conventionally produced broilers and turkeys, few studies have focused on free‐range (organic) or pastured poultry. The current surveillance study was designed to isolate, identify and genetically characterize Salmonella from pastured poultry farm environment and from retail samples. Methods and Results: In this study, 59 isolates were collected from two pastured poultry farms (n = 164; pens, feed, water and insect traps) and retail carcasses (n = 36) from a local natural foods store and a local processing plant. All isolates were serotyped and analysed phenotypically (antimicrobial resistance profiles) and genotypically (DNA fingerprints, plasmid profiles and integron analysis). Salmonella enterica was detected using standard microbiological methods. Salmonella Kentucky was the most prevalent serotype detected from the sampled sources (53%), followed by Salmonella Enteritidis (24%), Bareilly (10%), Mbandaka (7%), Montevideo (5%) or Newport (2%). All isolates were resistant to sulfisoxazole and novobiocin, and the majority (40/59) possessed class I integrons shown by PCR detection. Each Salmonella serotype elicited a distinct pulsed‐field gel electrophoresis fingerprint profile, and unique differences were observed among the serotypes. Conclusions: The findings of this study show that Salmonella serotypes isolated from pasture‐raised poultry exhibit antimicrobial resistance and class I integrons. Significance and Impact of the Study: This study demonstrates that despite the cessation of antibiotic usage in poultry production, antibiotic resistant Salmonella may still be recovered from the environment and poultry products.     

PCR identification of Salmonella cells in food and stool samples after immunomagnetic separation

The purpose of the present study was to investigate the application of various sample preparation methods (cell washing before lysis, purification of DNA using phenol extraction method, immunomagnetic separation-IMS) for the final PCR identification of Salmonellacells. The presence of PCR inhibitors in processed food products (milk powder and dried eggs) can be the cause of false-negative results in PCR without IMS of target cells. It was also demonstrated that IMS-PCR was successfully used for identification and quick confirmation of untypical Salmonella strains isolated from human stool samples and rabbit meat. However, IMS cannot eliminate intracellular PCR inhibitors present in immunoseparated Salmonella cells. These inhibitors must be taken into consideration in evaluation of PCR procedure.     

Microbial challenges of poultry meat production

Food safety and shelf-life are both important microbial concerns in relation to broiler meat production. Focus is mainly placed on the absence or control of potentially pathogenic microbes such as Salmonella spp. and Campylobacter spp. but, from the commercial point of view, other spoilage bacteria also play a role as potential threats. Regarding food safety, the primary target should be the production of pathogen-free live animals, thus allowing slaughter plants to keep the processing line free of those microorganisms.Consumers believe that quality of foods from organic production is superior to foods from conventional production. The aim of the present study was to evaluate and compare the bacterial quality of chicken meat from organic and conventional production on the basis of traditional meat quality criteria. Fresh free grazing broiler carcasses were purchased directly from rural households (n = 80) and fresh retail chicken parts from conventional broiler carcasses from the local supermarkets in the region of Epirus (Poultry Producers Association. Arta) (n = 200).The samples were microbiologically tested for the presence of bacteria such as: Salmonella spp., Listeria monocytogenes, Staphylococcus aureus, Enterobacteriaceae, Escherichia coli, Campylobacter spp., and C. perfringens. Total count of aerobic mesophilic bacteria was also determined. Bacteriological tests were performed by means of standard methods of isolation and identification of individual species of bacteria according to ISO requirements. API-tests (bioMerieux) and Vitek 2 Identification System (bioMerieux) were used for biochemical determination. High levels of microbial contamination and occurrence of pathogenic bacteria at then fresh free grazing broiler carcasses reflect the poor hygienic quality of the slaughter conditions in the rural households.     

Validation of a same-day real-time PCR method for screening of meat and carcass swabs for Salmonella

Background  

One of the major sources of human Salmonella infections is meat. Therefore, efficient and rapid monitoring of Salmonella in the meat production chain is necessary. Validation of alternative methods is needed to prove that the performance is equal to established methods. Very few of the published PCR methods for Salmonella have been validated in collaborative studies. This study describes a validation including comparative and collaborative trials, based on the recommendations from the Nordic organization for validation of alternative microbiological methods (NordVal) of a same-day, non-commercial real-time PCR method for detection of Salmonella in meat and carcass swabs.     

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.     

Heat inactivation of Salmonella spp. in fresh poultry compost by simulating early phase of composting process

Aims: The purpose of this study was to determine the effect of moisture on thermal inactivation of Salmonella spp. in poultry litter under optimal composting conditions. Methods and Results: Thermal inactivation of Salmonella was studied in fresh poultry compost by simulating early phase of composting process. A mixture of three Salmonella serotypes grown in Tryptic soy broth with rifampin (TSB‐R) was inoculated in fresh compost with 40 or 50% moisture at a final concentration of c. 7 log CFU g^?1. The inoculated compost was kept in an environmental chamber which was programmed to rise from room temperature to target composting temperatures in 2 days. In poultry compost with optimal moisture content (50%), Salmonella spp. survived for 96, 72 and 24 h at 50, 55 and 60°C, respectively, as compared with 264, 144 and 72 h at 50, 55 and 60°C, respectively, in compost with suboptimal moisture (40%). Pathogen decline was faster during the come‐up time owing to higher ammonia volatilization. Conclusions: Our results demonstrated that Salmonella spp. survived longer in fresh poultry compost with suboptimal moisture of 40% than in compost with optimal moisture of 50% during thermophilic composting. High nitrogen content of the poultry compost is an additional factor contributing to Salmonella inactivation through ammonia volatilization during thermal exposure. Significance and Impact of the Study: This research validated the effectiveness of the current composting guidelines on Salmonella inactivation in fresh poultry compost. Both initial moisture level and ammonia volatilization are important factors affecting microbiological safety and quality of compost product.     

Zn finger-based direct detection system for PCR products of<Emphasis Type="Italic"> Salmonella</Emphasis> spp. and the Influenza A virus

We have detected PCR products from Salmonella spp. and Influenza A virus using Zn finger protein Zif268 and Sp1, respectively. Previously, we demonstrated a novel method of rapid and specific detection of PCR products from Legionella pneumophila genome using Zn finger protein Sp1. In principle, this methodology might be applied to the detection of most bacteria and viruses using various Zn finger proteins. Here, to demonstrate the wider applicability of our method, we detected PCR products from Salmonella spp. and the Influenza A virus. BLAST data indicated the Zif268 and Sp1 recognition sequence were located on the gyrB gene of Salmonella spp. and the nucleoprotein gene of Influenza A virus, respectively. The PCR products from the oligonucleotide corresponding to the gyrB gene of Salmonella spp. or the nucleoprotein gene of the Influenza A virus could be specifically detected by ELISA or fluorescence depolarization measurement using Zif268 or Sp1. These results indicate the wide applicability of our novel methodology. An erratum to this article can be found at     

A mycological and bacteriological survey on feed ingredients and mixed poultry feeds in Reunion island

A survey was carried out in Reunion island to obtain data on the occurrence of fungi, aflatoxigenic strains of Aspergillus flavus, aflatoxins, total aerobic bacteria and salmonellae of 150 samples of mixed poultry feeds and raw materials. These were collected at five farms over a 3-month period during the warm rainy season.White corn and Brazilian soybean meal seemed to present a better microbiological quality than yellow corn and US soybean meal.Mixed poultry feeds presented a high total mold count reflecting the mold flora of raw materials. The most frequent and abundant fungi were Aspergillus flavus, A. glaucus group, Fusarium spp., Penicillium spp., A. candidus, Mucor spp., A. restrictus, Scopulariopsis spp., Cladosporium spp. and A. versicolor. Of the 118 A. flavus strains screened, 42 (35.6%) were aflatoxigenic. Yellow corn samples were the most frequently contamined with aflatoxigenic strains (54.5%), followed by mixed feeds (44%).Of the 66 samples tested, 24 (36%) contained aflatoxins (traces to 22 ng/g). A good correlation seemed to exist between presence of at least one aflatoxigenic strain per sample and presence of aflatoxins.     

Microbiological quality of walnut kernels and apple juice concentrate

In the present study, we have evaluated the microbiological quality of walnut kernels and pasteurized apple juice concentrate and the application of PCR for quality control of these important horticultural products. PCR assays for the detection of Bacillus cereus, Salmonella, Escherichia coli and E. coli O157:H7 were standardized using minimum time for each step of the reaction. The protocols were effective for their detection in these products after pre-enrichment for 6–12 h. 2, 68 and 30% of the samples of walnut kernels were respectively found satisfactory, acceptable and unsatisfactory on the basis of their viable count. Only 15% of the samples of pasteurized apple juice concentrate were found to possess the desired viable count of less than 100 c.f.u./ml. The predominant contaminants of walnut kernels were found to be the species of Bacillus, Klebsiella, Enterobacter and Staphylococcus. Samples of apple juice concentrate were predominantly found contaminated with species of Bacillus, Staphylococcus and Micrococcus. However, B. cereus, Salmonella and E. coli were also isolated from some of the samples of walnut kernels. Bacillus cereus was also obtained from some of the samples of pasteurized apple juice concentrate in high numbers. Among the moulds Penicillium, Aspergillus, Cladosporium, Rhizopus and Mucor were isolated from these products.     

Microbiological analysis of composts produced on South Carolina poultry farms

Aims: The purpose of this study was to determine whether the methods used in compost operations of small and medium‐sized poultry forms resulted in the production of an amendment free of foodborne pathogens. Methods and Results: Nine compost heaps on five South Carolina poultry farms were surveyed at different stages of the composting process. Compost samples were analysed for coliforms and enriched for Escherichia coli O157:H7, Salmonella spp. and Listeria monocytogenes. The waste materials and composting practices differed among the surveyed farms. On two farms, new materials were added to heaps that had previously completed the active composting phase. Five compost heaps did not reach an internal temperature of 55°C, and c. 62% of all internal samples in the first composting phase contained moisture contents <40%. Escherichia coli was detected in 63% of the surface samples (n = 38) and 9·8% of the internal samples (n = 82) from the first composting phase, as compared with 16·7% of the surface samples (n = 12) and 0% internal samples (n = 24) from the second composting phase. Salmonella was detected in 26 and 6·1% of all surface and internal samples collected from heaps in the first composting phase, respectively, but was absent in all compost samples undergoing a second composting phase. The predominant Salmonella serotypes were Thompson, Montevideo and Anatum. Neither E. coli O157:H7 nor L. monocytogenes was detected in any of the samples. Conclusions: Our results indicate that the conditions at the compost surface are suitable for pathogen survival, and the complete composting process can result in the elimination of pathogens in poultry wastes. Significance and Impact of the Study: This research provides information regarding the effectiveness of the composting practices and microbiological quality of poultry compost produced by small‐ and medium‐sized farms. Ensuring the safety of compost that may be applied to soils should be an integral part of preharvest food safety programme.     

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 × 10² and 4 × 10¹ 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.     

Gold nanoparticles-based colorimetric assay for rapid detection of Salmonella species in food samples

A rapid, sensitive and cost-effective method was developed for detection of foodborne pathogens, particularly Salmonella species. The method utilizes single stranded DNA (ssDNA) probes and non-functionalized gold nanoparticles to provide a colorimetric assay for the detection of PCR amplified DNA. Different food samples were tested with the PCR-based colorimetric assay parallel with the conventional culture method. The sensitivity and specificity of colorimetric assay was 89.15 and 99.04% respectively with reference to conventional culture method. The total time required to detect the Salmonella spp. present in food samples by the developed method is less than 8 h, including 6 h incubation. It was observed that the colorimetric assay was 10 times more sensitive than gel-based detection with the same concentration of DNA used for analysis.     

Virulotyping of <Emphasis Type="Italic">Salmonella enterica</Emphasis> subsp. <Emphasis Type="Italic">enterica</Emphasis> isolated from indigenous vegetables and poultry meat in Malaysia using multiplex-PCR

The increased occurrence of Salmonella occurrence in local indigenous vegetables and poultry meat can be a potential health hazards. This study is aimed to detect the prevalence of twenty different virulence factors among Salmonella enterica strains isolated from poultry and local indigenous vegetables in Malaysia via an optimized, rapid and specific multiplex PCR assay. The assay encompasses a total of 19 Salmonella pathogenicity islands genes and a quorum sensing gene (sdiA) in three multiplex reaction sets. A total of 114 Salmonella enterica isolates belonging to 38 different serovars were tested. Each isolate in under this study was found to possess up to 70% of the virulence genes tested and exhibited variable pathogenicity gene patterns. Reproducibility of the multiplex PCR assay was found to be 100% and the detection limit of the optimized multiplex PCR was tested with lowest detectable concentration of DNA 0.8 pg μl⁻¹. This study demonstrated various Salmonella pathogenicity island virulence gene patterns even within the same serovar. This sets of multiplex PCR system provide a fast and reliable typing approach based on Salmonella pathogenicity islands, thus enabling an effective monitoring of emerging pathogenic Salmonella strains as an additional tool in Salmonella surveillance studies.     

Assessment of microbial quality of commercial and home-made tiger-nut beverages

Aims: We aimed to assess the microbiological quality of Spanish commercial tiger‐nut beverages as well as home‐made samples collected from supermarkets, street vendors, juice bars and ice‐cream parlours located in Valencia. Methods and Results: Microbiological analysis of 44 tiger‐nut beverages samples were carried out according to International Standard Organization (ISO) norms and published works which included the total viable count, Enterobacteriaceae, Escherichia coli, Staphylococcus aureus, Salmonella, Bacillus cereus, yeasts, moulds, Yersinia enterocolitca, Clostridium perfringens, Vibrio spp. and Listeria monocytogenes. The obtained results indicated that all the commercial samples were below the detection limit for the viable microorganisms. Results of analysis of those home‐made tiger‐nut samples revealed that 67% (16 samples) harboured total plate counts while the rest of samples were free from these microorganisms. Enterobacteriaceae were detected in 62% (15 samples). E. coli were found in only one sample (4%), yeasts and moulds were detected in 62% (15 samples) each, Shigella was found in 21% (five samples); however, all samples were free from S. aureus, Salmonella, Y. enterocolotica, C. perfringens, Vibrio spp. and L. monocytogenes. Conclusions: These results reflected that there exists a rather high contamination level in home‐made tiger‐nut beverages indicating the need to apply correct and strict HACCP system(s) during manufacturing and storage of these food products. Significance and Impact of Study: This study demonstrates the great need to carry out microbiological tests frequently in these products and even more the need to apply correct HACCP system (s). Tiger‐nut beverages are especially well‐known products in Spain, hence it is extremely important to ensure an adequate microbiological quality to guarantee consumers health.     

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 simultaneous screening of seven clinically important enteric pathogens using a magnetic bead based DNA microarray

In this study, we describe a DNA microarray assay by using bead-mediated visible light-assisted signal detection for simultaneous screening of seven clinically important enteric pathogens, including Escherichia coli O157:H7, Vibrio cholerae, Vibrio parahaemolyticus, Salmonella spp., Staphylococcus aureus, Rotavirus, and Norwalk virus (including genogroup I and II). Seven pairs of primers, in which the forward primers were labeled with biotin at the 5′ end, were designed and two sets of multiplex asymmetric PCR system were established to amplify the target genes of the seven pathogens. Twelve type specific oligonucleotides were designed and immobilized onto the aldehyde radical modified glass slide to function as target capture probes. After hybridization and stringency washes, the hybridized biotinylated PCR products were detected by the streptavidin-coated magnetic beads. The final hybridization results were visible to the naked eyes and can be imaged by CCD or digital camera. A total of 86 samples previously identified by conventional microbiological methods and/or PCR method were randomly selected to assess the specificity of this assay by a blind study. A coincidence rate of 100% was obtained. Due to the simplicity and specificity of the magnetic bead based DNA microarray, it is especially appropriate for the diagnosis and monitoring of enteric infectious diseases in the community and seaport.     

Microbiological evaluation of pequi (<Emphasis Type="Italic">Caryocar brasiliense</Emphasis> Camb.) preserves made from a typical Brazilian fruit

The microbiological quality of preserves made from the pulp of the pequi (Caryocar brasiliense Camb.), a typical Brazilian fruit, was assessed. The total aerobic mesophilic and the yeast and mould counts in the samples suggest inadequate hygienic conditions during the processing of the product. Low levels of contamination by coliform bacteria and enterobacteria were observed; however, the presence of injured cells of these microorganisms was demonstrated. The presence of Staphylococcus aureus and sulfite-reducing clostridia was not shown. Salmonella spp. was found in 33% of the samples analysed, indicating that the product can represent a public health risk.     

Prevalence and numbers of Salmonella spp. and Enterobacteriaceae on pork cuts in abattoirs in the Republic of Ireland

Aims: This study aimed to determine the numbers and types of Salmonella spp. and Enterobacteriaceae on pork cuts in the meat cutting room environment of four commercial pork abattoirs in the Republic of Ireland. Methods and Results: Pork oysters (M. gluteus medius; n = 720) and swabs (n = 56) from equipment and surfaces were screened for Salmonella spp. using a DNA-based PCR method and confirmed by culture. Salmonella numbers were assessed using a three-tube most probable number (MPN) technique. Salmonella spp. was detected on 24/720 (3·3%) pork cuts (range of <0·03–0·36 MPN g⁻¹) and in 7/56 (12·5%) environmental swabs (range of <0·03–1·10 MPN cm⁻²). There was significant variation in the prevalence of Salmonella on pork between different abattoirs and days of sampling (range of 0–31·7%). The predominant serotype was Salmonella serotype Typhimurium followed by Salmonella serotype Derby. Conclusions: Overall prevalence data conceal the key finding that there was considerable variation in the incidence of Salmonella on different days. A direct association between Salmonella contamination of pork cuts and equipment/surfaces was observed. Significance and Impact of the Study: Prevalence and numbers of Salmonella were low; however, results clearly demonstrate the potential for cross-contamination from equipment and meat contact surfaces in the cutting room environment.     

Physical, chemical and microbiological quality of ice used to cool drinks and foods in Greece and its public health implications

Ice used for direct human consumption or to preserve foods and cool down drinks can be contaminated with pathogenic microorganisms and may potentially become a vehicle for consumer’s infection. To evaluate physical, chemical and microbiological quality of commercial ice and ice used for fish and seafood, 100 ice samples collected at 10 different retail points in the region of Epirus were studied. The following microbiological parameters were determined: Total coliforms, fecal coliforms, Salmonella spp., Shigella spp., Yersinia spp., Escherichia coli, Campylobacter sp., Vibrio cholerae, Aeromonas spp., Pseudomonas aeruginosa and Clostridium perfringens.E. coli was detected in 22% and coliforms were detected in 31% of samples. Samples in which coliforms were detected fail to meet the microbiological criteria specified by the drinking water legislation.Aeromonas spp., Shigella spp., Campylobacter sp. and V. cholerae were not detected. Spore forms of C. perfringens were prevalent at 35% and the psychotropic bacterium’s P. aeruginosa and Yersinia spp. were found only at three samples each.The presence of large numbers of coliforms as well as of other pathogenic strains suggested that commercial ice and ice used to make cool drinks or in preservation of fish and seafood may represent a potential hazard to the consumer. In view of the results reported herein, it is highly recommended that national regulatory guidelines should be established for the production of ice as long as regular inspections.     

An eight-hour PCR-based technique for detection of <Emphasis Type="Italic">Salmonella</Emphasis> serovars in seafood

A rapid and sensitive 8-h PCR assay has been developed for detection of Salmonella serovars in seafood. A total of 110 fresh and raw seafood samples were analysed for the presence of Salmonella using different enrichment periods prior to PCR assay. Seafood samples included in this study were fish, shrimps, mussels, crabs, edible oysters, and clams, collected from local fish markets in Cochin (India). The assay was performed with a Salmonella-specific 284 bp invA gene amplicon. Specificity and sensitivity of the assay were ascertained with seafoods spiked with viable Salmonella cells to a level of 10⁶ to 2 CFU per 25 g. Detection efficiency of the assay increased with increasing enrichment period for seafood, and 33.6% of seafood samples were found positive for Salmonella by 8-h PCR assay. Detection limit for the 8-h PCR assay showed visible 284 bp amplicon from seafood homogenates spiked with 2 CFU per 25 g. Seafood samples spiked with different Salmonella serovars, namely Salmonella typhi, Salmonella typhimurium, Salmonella enteritidis, Salmonella mbandka, Salmonella bareilly, and Salmonella weltevreden, were detected, confirming this technique would be ideal for detection of the Salmonella serovars prevalent in seafood. This study also covered inhibition by the seafood matrix and the detection limit for dead Salmonella cells during the PCR assay. There was no visible inhibition of this Salmonella PCR assay by seafood matrices. The detection limit for dead Salmonella cells by 8-h PCR assay was 2 × 10³ CFU per 25 g seafood. The data indicated that dead cells of Salmonella in naturally contaminated seafood samples do not interfere with the assay resulting in false positives.