Selective Plating Research Articles

Patterning and formation of copper electroplated contact for bifacial silicon hetero-junction solar cell

In this work, tungsten doped indium oxide (IWO) film was deposited as anti-reflection coating and conductive layer for silicon hetero-junction (SHJ) solar cell, which meant the necessity to mask the pattern of grid electrodes for selective plating. We investigated the plating process and compared three different masking resists suitable for large area SHJ solar cells. The results revealed that light-sensitive dry film was appropriate as plating resist due to its simple process, high resolution and rectangular shape. As a proof of concept, copper plated SHJ solar cell with an efficiency of 22% was fabricated in SIMIT’s R&D line. Compared with screen printed finger, copper plated finger showed narrow width, higher aspect ratio and lower bulk resistivity, leading to decreased shading loss without increasing girds power loss. The metallization refinement contributed 2.80% of power loss reduction, which indicated the possibility to achieve higher efficiency by copper metallization after well optimization.

Magnetically Driven Micromachines Created by Two-Photon Microfabrication and Selective Electroless Magnetite Plating for Lab-on-a-Chip Applications

We propose a novel method to fabricate three-dimensional magnetic microparts, which can be integrated in functional microfluidic networks and lab-on-a-chip devices, by the combination of two-photon microfabrication and selective electroless plating. In our experiments, magnetic microparts could be successfully fabricated by optimizing various experimental conditions of electroless plating. In addition, energy dispersive X-ray spectrometry (EDS) clarified that iron oxide nanoparticles were deposited onto the polymeric microstructure site-selectively. We also fabricated magnetic microrotors which could smoothly rotate using common laboratory equipment. Since such magnetic microparts can be remotely driven with an external magnetic field, our fabrication process can be applied to functional lab-on-a-chip devices for analytical and biological applications.

The combined effect of bacteriocin-producing Lactobacillus rhamnosus GG-ATCC and Lactoperoxidase system activation on microbiological quality of raw milk with special emphasis against E.coli O157:H7 in milk

Isolates of Enterohaemorrhagic E.coli O157:H7 were isolated from 51 and 41 of locally produced bovine and ovine soft cheese samples. Their identification were confirmed based on the biochemical reactions and both the morphological cultural and serological properties. Presumptive E.coli O157:H7 isolates obtained by using the conventional selective plating on the chromogenic agar were tested further for the presence of both O157 and H7 antigenes using the latex agglutination test antisera. The current microbiological studies revealed that 31 (33.70 %) out of 92 bovine and ovine soft cheese samples were positive for E.coli O157:H7. The highest non significant (P>0.05) prevalence level of E.coli O157:H7 was found in the ewe᾿s soft cheese samples (36.59 %) followed by cow᾿s soft cheese samples (31.37 %). Agar well diffusion bioassay method was used for measuring the antibacterial activity of the crude bacteriocin that was produced by Lactobacillus rhamnosus GG-ATCC against Escherichia coli and the closely related sensitive strains such as L.acidophilus LA-K and L.acidophilus ROO52. The crude bacteriocin that was produced by the L.rhamnosus GG-TACC exhibited significantly (P<0.05) the highest antibacterial potency (100 %) against both the closely related strains of lactobacilli and the stressed E.coli O157:H7 by the activation of the LPS. The activation of the natural LPS of inoculated pasteurized milk had significantly (P<0.05) influenced the inactivation degree of the crude bacteriocin against E.coli O157:H7. There was a significant (P<0.05) reduction in the viable counts of stressed E.coli O157:H7 after each exposure time period (6, 24 and 48 hrs.) to the crude bacteriocin at room storage temperature. An overall conclusion on the basis of the current results pointed out that complete elimination of viable bacterial cells was not achieved neither in the stabilized milk (Activation of LPS) nor after subjecting the stabilized milk to the action of the crude bacteriocin produced by L.rhamnosus GG-ATCC at room storage temperature.

An advanced selective liquid-metal plating technique for stretchable biosensor applications.

This paper presents a novel stretchable pulse sensor fabricated by a selective liquid-metal plating process (SLMP), which can conveniently attach to the human skin and monitor the patient's heartbeat. The liquid metal-based stretchable pulse sensor consists of polydimethylsiloxane (PDMS) thin films and liquid metal functional circuits with electronic elements that are embedded into the PDMS substrate. In order to verify the utility of the fabrication process, various complex liquid-metal patterns are achieved by using the selective wetting behavior of the reduced liquid metal on the Cu patterns of the PDMS substrate. The smallest liquid-metal pattern is approximately 2 μm in width with a uniform surface. After verification, a transparent flowing LED light with programmed circuits is realized and exhibits stable mechanical and electrical properties under various deformations (bending, twisting and stretching). Finally, based on SLMP, a wireless pulse measurement system is developed which is composed of the liquid metal-based stretchable pulse sensor, a Bluetooth module, an Arduino development board, a laptop computer and a self-programmed visualized software program. The experimental results reveal that the portable non-invasive pulse sensor has the potential to reduce costs, simplify biomedical diagnostic procedures and help patients to improve their life in the future.

Prevalence and Antimicrobial Susceptibility of E. coli and Salmonella Spp. in Market Show Cattle and Swine

ObjectivesThe objective of this study was to determine the prevalence and antimicrobial susceptibility of generic Escherichia coli and Salmonella spp. in feces of market show steers and hogs from a state wide livestock show.Materials and MethodsFecal samples were collected from market steers (n = 84) and hogs (n = 84) at a statewide livestock show, stored at 4°C and processed within 36 h of collection. Fecal samples were processed using 3M E. coli/Coliform Count Plates for enumeration and isolated onto MacConkey Agar for susceptibility testing. Salmonella prevalence was determined using selective enrichment in Rappaport Vassiliadis and Tetrathionate broths and selective plating on XLT4 agar. Salmonella spp. isolates, which were confirmed positive via latex agglutination, were utilized for antimicrobial susceptibility testing. Antimicrobial susceptibility testing was conducted with a microbroth dilution method using Sensititre plates from Trek Diagnostic. Isolates were tested against 14 antimicrobial agents important to both human and animal health, including: Cefoxitin, Azithromycin, Chloramphenicol, Tetracycline, Ceftriaxone, Amoxicillin/Clavulanic Acid, Ciprofloxacin, Gentamicin, Nalidixic Acid, Ceftiofur, Sulfisoxazole, Trimethoprim/Sulfamethoxazole, Ampicillin, and Streptomycin. Resistance breakpoints used were published in the NARMS 2014 Human Isolates Surveillance Report. Data was analyzed using procedures of SAS (Version 9.1.3; SAS Inst. Inc., Cary, NC).ResultsAs E. coli can serve as a vehicle for resistance genetics, fecal samples were analyzed for its presence and antibiotic resistance. E. coli populations were higher in hogs with 6.12 log10 CFU/g of feces compared to steer samples at 5.57 log10 CFU/g (P < 0.05). Of the 662 E. coli isolates, 98.18% (324 of 330 tested) of hog isolates and 63.25% (210 of 332 tested) of steer isolates exhibited resistance to at least 1 antimicrobial. Within isolates from hogs, the most common resistance was to Tetracycline, Sulfisoxazole, and Streptomycin with 96.67, 69.70, and 53.64% of isolates exhibiting resistance to the respective antimicrobial. Escherichia coli isolates from steers exhibited the most common resistance to Tetracycline, Streptomycin, and Sulfisoxazole with 55.12, 32.53, and 28.61% of isolates exhibiting resistance, respectively.Salmonella was more prevalent in hog samples than steer samples (P < 0.05) with 19.05% of hogs (16 of 84) and 3.61% steers (3 of 83) testing positive. Of the 18 Salmonella isolates from hog samples, 83.33% exhibited resistance to at least 1 antimicrobial. Isolates from market hogs exhibited the most common resistance to Tetracycline, Streptomycin, and Sulfisoxazole with 77.78, 44.44 and 44.44% of isolates resistant to the respective antimicrobial. Conversely, none of the Salmonella isolates from steers exhibited clinical resistance to any of the antimicrobials.ConclusionLittle research has been done on the antimicrobial susceptibility of bacteria in show animals. Results from this study indicate that market show hogs had higher levels the bacteria of interest and isolates from hogs were consistently more resistant to the tested antimicrobial agents when compared to steers. While making up a small percentage of the overall industry, show animals that are designated “market livestock” will eventually be introduced to the human food supply and play a role in its safety.

Fecal carriage of extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella spp. in a Turkish community.

The aim of this study was to determine the prevalence of fecal carriage of extended-spectrum beta-lactamase (ESBL)-producing bacteria, enzyme types, and risk factors affecting colonization. A total of 576 stool samples from outpatients were examined between October 2012 and May 2013. Screening was done with selective EMB plates. ESBL were detected by double-disk synergy and confirmed agar strip gradient methods. Enzyme types were determined by PCR. The prevalence of fecal carriage was found as 30% (173 of 576). Recent use of antibiotics, hospitalization and surgical operation, diabetes, crowded household populations, and old age were associated with higher carriage rates. Of the ESBL-producing bacteria, 87.5% were positive for blaCTX-M genes. Of the blaCTX-M gene-positive isolates, 95.2% were positive for blaCTX-M-1 genes; among these, 82.2% were positive for blaCTX-M-3 and 67.7% were positive for blaCTX-M-15 genes while 62.5% isolates were positive for both blaCTX-M-3 and blaCTX-M-15 genes Conclusions: A high rate (30%) of fecal carriage of ESBL bacteria was found in an adult population. The predominant beta-lactamase enzyme types were CTX-M-3 and CTX-M-15.

Evaluation of Gut Associated Extracellular Enzyme-producing and Pathogen Inhibitory Microbial Community as Potential Probiotics in Nile Tilapia, &lt;i&gt;Oreochromis niloticus&lt;/i&gt;

The present study aimed at evaluation of gut associated bacteria and yeasts in Nile tilapia ( Oreochromis niloticus ) as novel probiotics depending on extracellular digestive (amylase, protease and lipase) and degradation (cellulase, phytase, and xylanase) enzymes-producing ability, pathogen inhibition and bio-safety. The gastrointestinal (GI) tracts were taken out, separated into proximal and distal segments, homogenized, and enrichment culture was done on selective media plates for isolation of bacteria. Yeasts were isolated on yeast extract-peptone-dextreose media supplemented with antibiotics (150 mg L -1 ). Both, bacteria and yeasts were detected in the GI tracts of Nile tilapia. Diverse enzyme-producing microbial populations were higher in the distal segment than the proximal segment. Ten out of 97 bacteria and 5 out of 32 yeast strains were primarily selected. The bacterium ONF1P and the yeast strain ONF7.1C were noticed as the efficient exo-enzyme producing strains. Both the isolates were antagonistic against ≥2 tested fish pathogens. Both the strains were tolerant to diluted bile juice, capable to grow in fish mucus (intestinal) and compatible with previously isolated autochthonous fish gut bacteria. The isolates didn’t induce any pathological lesions or mortality in O. niloticus fingerlings. The strains ONF1P and ONF7.1C were identified as Bacillus licheniformis (KT362744) and Pichia kudriavzevii (KT582009), respectively, through 16S /18S rRNA gene fragment analyses. Extracellular enzyme-producing gut bacteria and yeast may restrain the growth of some fish pathogens and tolerate conditions within the GI tract. Further research should be directed to determine their in vivo effects on growth and disease resistance in O. niloticus .

Postnatal changes in the relative abundance of intestinal Lactobacillus spp. in newborn calves.

The intestinal microbiota of newborn calves changes during the early postnatal period and influences their health and immune function. We studied the compositional changes in the intestinal microbiome of newborn calves during the first week after birth by metagenomic analysis. In feces from newborn calves, we identified 4 bacterial phyla, namely, Actinobacteria, Bacteroidetes, Firmicutes and Proteobacteria. The relative abundance of Lactobacillaceae significantly increased from day 1 to day 7. We evaluated Lactobacillus spp. colony numbers using selective agar plates and confirmed that the abundance of Lactobacillus spp. significantly increased during the first 7 days after birth. In conclusion, Lactobacillus spp. colonized the intestinal tract of calves during the first 7 days after birth.

Salmonella Contamination in Poultry—Are We Missing a Potential Vector?

ObjectivesIn the third quarter of 2015, USDA Salmonella prevalence in young chicken carcasses and chicken parts was 1.4 and 22.1%, respectively. These data indicate that efforts to control carcass contamination are effective; however, the relatively high prevalence in chicken parts suggests the pathogen is somehow evading carcass decontamination strategies. Thus, the objectives of this study were to assess the presence of Salmonella enterica in an alternative carcass location, namely joint synovial fluid, and further, to characterize any recovered Salmonella isolates.Materials and MethodsThe synovial fluid of 3 unique true joints (shoulder, coxofemoral, and stifle) of 500 broiler carcasses were individually sampled (1500 total samples) and analyzed for Salmonella presence. Broiler carcasses were collected immediately post chilling from 3 conventional and 2 antibiotic free broiler processing facilities located in the Southeast and Western United States. Each processing location was sampled twice during the study period. Broiler carcasses were subjected to a decontamination protocol to reduce the potential of cross-contamination of the joint synovial fluid from the carcass surface. The decontamination protocol included immersing the carcass in ethanol, flame sterilization, removing the carcass skin around the joint to be sampled and finally, immersion in boiling water (10 s). The joints to be sampled were then aseptically exposed using a sterile scalpel. The synovial fluid of the 3 joints was individually sampled, using a sterile swab, and the swab was enriched (35°C, 22 h) in buffered peptone water. Enriched synovial fluid samples from each bird (n = 3 joints per bird) were composited and subjected to rapid-based PCR Salmonella detection. If the composite sample was deemed a presumptive positive, the individual enriched synovial samples were further subjected to rapid based PCR Salmonella detection. Individual samples deemed a presumptive positive were subjected to secondary enrichment and selective agar plating (Brilliant Green Sulfa Agar and XLT4 Agar) to facilitate isolation of Salmonella. Presumptive Salmonella isolates were serotyped prior to determination of antimicrobial susceptibility.ResultsOverall, the prevalence of presumptive positive Salmonella among all joints for all birds was 0.47% (7 out of 1500 samples) with a 95% confidence interval of 0.20 to 1.00%. The prevalence of presumptive positive Salmonella among the antibiotic free and conventionally raised broilers was 0.17 and 0.67%, respectively. Among regions, presumptive positive Salmonella prevalence tended to be greater in the Southeast (0.83%) versus the Western region (0.22%). Among joint types, prevalence was greater in the shoulder joint (0.80%) when compared to the coxofemoral (0.40%) and stifle (0.20%) joints, respectively.ConclusionTo our knowledge, no previous assessments of Salmonella in the synovial fluid of broilers exists. However, as the presence of Salmonella in ground poultry and poultry parts remains problematic, alternative vectors for Salmonella should be evaluated. These results suggest that Salmonella may be present in the synovial fluid of broilers. Although prevalence is relatively low, when extrapolated to the scale of broilers produced, this information provides valuable insight into potential poultry contamination pathways. Further evaluation of this pathway is warranted.

Identification of Bacterial Species in Kuwaiti Waters Through DNA Sequencing

With an objective of identifying the bacterial diversity associated with ecosystem of various Kuwaiti Seas, bacteria were cultured and isolated from 3 water samples. Due to the difficulties for cultured and isolated fecal coliforms on the selective agar plates, bacterial isolates from marine agar plates were selected for molecular identification. 16S rRNA genes were successfully amplified from the genome of the selected isolates using Universal Eubacterial 16S rRNA primers. The resulted amplification products were subjected to automated DNA sequencing. Partial 16S rDNA sequences obtained were compared directly with sequences in the NCBI database using BLAST as well as with the sequences available with Ribosomal Database Project (RDP).

Formation of Fine Metal Patterns by Selective Electroless Plating on Cyclic Olefin Polymer using Vacuum Ultra Violet Light Surface Modification

Formation of Fine Metal Patterns by Selective Electroless Plating on Cyclic Olefin Polymer using Vacuum Ultra Violet Light Surface Modification

Copper circuit patterning on polymer using selective surface modification and electroless plating

We have examined a potential new and simple method for patterning a copper circuit on PET substrate by copper electroless plating, without the pretreatment steps (i.e., sensitization and activation) for electroless plating as well as the etching processes of conventional circuit patterning. A patterned mask coated with a catalyst material, Ag, for the reduction of Cu ions, is placed on a PET substrate. Subsequent oxygen plasma treatment of the PET substrate covered with the mask promotes the selective generation of anisotropic pillar- or hair-like nanostructures coated with co-deposited nanoparticles of the catalyst material on PET. After oxygen plasma treatment, a Cu circuit is well formed just by dipping the plasma-treated PET into a Cu electroless plating solution. By increasing the oxygen gas pressure in the chamber, the height of the nanostructures increases and the Ag catalyst particles are coated on not only the top but also the side surfaces of the nanostructures. Strong mechanical interlocking between the Cu circuit and PET substrate is produced by the large surface area of the nanostructures, and enhances peel strength. Results indicate this new simple two step (plasma surface modification and pretreatment-free electroless plating) method can be used to produce a flexible Cu circuit with good adhesion.

Carriage of ESBL/AmpC-producing or ciprofloxacin non-susceptible Escherichia coli and Klebsiella spp. in healthy people in Norway.

BackgroundAsymptomatic carriage has been recognised as an important risk factor for infection caused by antibiotic resistant bacteria. A 14% global prevalence of Extended-Spectrum Beta-lactamase (ESBL) carriage was recently reported, but large intra-and interregional variations were observed. We investigated the faecal carriage rates of ESBL-, AmpC-producing and ciprofloxacin non-susceptible Escherichia coli and Klebsiella spp. in healthy Norwegians.MethodsRectal samples were obtained from 284 volunteers, together with demographic data and information on recent travel history. The rectal samples were screened by selective plating and E. coli and Klebsiella spp. identified using MALDI-TOF. Phenotypic and molecular characterization of resistant isolates was also performed.ResultsESBL- or AmpC-producing E. coli and Klebsiella spp. were isolated from 4.9% and 3.2% of the study population, respectively. Carriage of ciprofloxacin non-susceptible isolates was detected in 9.9% of the volunteers. Molecular typing of ESBL/plasmid-mediated AmpC (pAmpC)-producing isolates suggested an allodemic situation rather than the dissemination of a specific clone in the Norwegian community. In concurrence with previous findings, travel to South-East Asia was associated with increased risk of carrying resistant E. coli or Klebsiella spp., highlighting the contribution of factors such as increased global mobility in erasing the boundaries between healthcare and community settings when it comes to spread of resistant bacteria.ConclusionsOverall, our study recognised Norway as a low-incidence country for faecal carriage of resistant bacteria among healthy individuals. Furthermore, our work denoted the importance of healthy humans as a reservoir for transmission of antibiotic resistant E. coli and Klebsiella spp.Electronic supplementary materialThe online version of this article (doi:10.1186/s13756-016-0156-x) contains supplementary material, which is available to authorized users.

Variation in Campylobacter Multilocus Sequence Typing Subtypes from Chickens as Detected on Three Plating Media

The objective of this study was to compare subtypes of Campylobacter jejuni and Campylobacter coli detected on three selective Campylobacter plating media to determine whether each medium selected for different subtypes. Fifty ceca and 50 carcasses (representing 50 flocks) were collected from the evisceration line in a commercial broiler processing plant. Campylobacter was cultured and isolated from cecal contents and carcass rinses on Campy-Cefex, Campy Line, and RF Campylobacter jejuni/coli agars. When a positive result was obtained with all three media, one colony of the most prevalent morphology on each medium was selected for further analysis by full genome sequencing and multilocus sequence typing. Sequence types were assigned according to PubMLST. A total of 49 samples were positive for Campylobacter on all three media. Forty samples contained only C. jejuni , three had only C. coli , and both species were detected in six samples. From 71% of samples, Campylobacter isolates of the same sequence type were recovered on all three media. From 81.6% of samples, isolates were all from the same clonal complex. From significantly fewer samples (26%, P < 0.01), one medium recovered an isolate with a sequence type different from the type recovered on the other two media. When multiple sequence types were detected, six times the medium with the odd sequence type was Campy-Cefex, four times it was Campy-Line, and six times it was RF Campylobacter jejuni/coli . From one sample, three sequence types were detected. In most cases, all three plating media allowed detection of the same type of Campylobacter from complex naturally contaminated chicken samples.

Population Screening Using Sewage Reveals Pan-Resistant Bacteria in Hospital and Community Samples.

The presence of pan-resistant bacteria worldwide possesses a threat to global health. It is difficult to evaluate the extent of carriage of resistant bacteria in the population. Sewage sampling is a possible way to monitor populations. We evaluated the presence of pan-resistant bacteria in Israeli sewage collected from all over Israel, by modifying the pour plate method for heterotrophic plate count technique using commercial selective agar plates. This method enables convenient and fast sewage sampling and detection. We found that sewage in Israel contains multiple pan-resistant bacteria including carbapenemase resistant Enterobacteriacae carrying blaKPC and blaNDM-1, MRSA and VRE. blaKPC carrying Klebsiella pneumonia and Enterobacter cloacae were the most common Enterobacteriacae drug resistant bacteria found in the sewage locations we sampled. Klebsiella pneumonia, Enterobacter spp., Escherichia coli and Citrobacter spp. were the 4 main CRE isolated from Israeli sewage and also from clinical samples in our clinical microbiology laboratory. Hospitals and Community sewage had similar percentage of positive samplings for blaKPC and blaNDM-1. VRE was found to be more abundant in sewage in Israel than MRSA but there were more locations positive for MRSA and VRE bacteria in Hospital sewage than in the Community. Therefore, our upgrade of the pour plate method for heterotrophic plate count technique using commercial selective agar plates can be a useful tool for routine screening and monitoring of the population for pan-resistant bacteria using sewage.

Pathogenic bacteria and heavy metals toxicity assessments in evaluating unpasteurized raw milk quality through biochemical tests collected from dairy cows

ObjectiveTo evaluate the hygienic quality by determining the presence of predominant pathogenic microbial contaminants (contagious or environmental) and indiscriminate heavy metals contained in unpasteurized milk samples collected from cattle specie of cow. MethodsRaw milk samples were collected in October, 2014 from different regions of District Kohat, Khyber Pakhtunkhwa, Pakistan and cultured on the selective media plates according to the manufacturer instructions to observe pathogenic microbial flora and confirm it with relevant biochemical tests to specify bacterial specie. ResultsMilk samples analyzed on MacConkey and nutrient agar media were found contaminated mostly with coliform, Staphylococcus aureus, Enterobacter aerogenes and Proteus vulgaris. Similarly, result of the heavy metals analysis performed using atomic absorption spectrophotometer flame photometry showed that raw milk contains heavy metals residues of lead and cadmium contents at higher levels while copper, zinc and chromium were observed lower than permissible limits whereas manganese within specified recommended values. ConclusionsMicrobial contamination of milk and toxic metals is mainly accredited to the scrupulous unhygienic measures during processing of milk exhibiting a wide array of hazardous impacts on human health.

Bacteria in the apical root canals of teeth with apical periodontitis.

Bacteria in the tooth root canal may cause apical periodontitis. This study examined the bacterial species present in the apical root canal of teeth with apical periodontitis. Antibiotic sensitivity tests were performed to evaluate whether these identified bacterial species were susceptible to specific kinds of antibiotics. Selective media plating and biochemical tests were used first to detect the bacterial species in samples taken from the apical portion of root canals of 62 teeth with apical periodontitis. The isolated bacterial species were further confirmed by matrix-assisted laser desorption ionization-time of flight mass spectrometry. We found concomitant presence of two (32 teeth) or three species (18 teeth) of bacteria in 50 (80.6%) out of 62 tested teeth. However, only 34 bacterial species were identified. Of a total of 118 bacterial isolates (83 anaerobes and 35 aerobes), Prophyromonas endodontalis was detected in 10; Bacteroides, Dialister invisus or Fusobacterium nucleatum in 9; Treponema denticola or Enterococcus faecalis in 8; Peptostreptococcus or Olsenella uli in 6; and Veillonella in 5 teeth. The other 25 bacterial species were detected in fewer than five teeth. Approximately 80-95% of bacterial isolates of anaerobes were sensitive to ampicillin/sulbactam (Unasyn), amoxicillin/clavulanate (Augmentin), cefoxitin, and clindamycin. For E. faecalis, 85-90% of bacterial isolates were sensitive to gentamicin and linezolid. Root canal infections are usually caused by a mixture of two or three species of bacteria. Specific kinds of antibiotic can be selected to control these bacterial infections after antibiotic sensitivity testing.

Prevalence of Campylobacter jejuni and Campylobacter coli in raw milk and some dairy products.

Aim:This study was accomplished to test raw milk and certain dairy products sold in local markets of Qena, Egypt, for the presence of Campylobacter coli and Campylobacter jejuni.Materials and Methods:A total of 150 samples of raw milk, kareish cheese, and yoghurt (50 samples each) were subjected first to enrichment in Bolton broth at 42°C for 2 days under a microaerobic condition, subsequently campylobacter blood free selective agar plates were cultured and incubated in the same condition of the broth. Based on the morphological and biochemical themes of the growing colonies, it was further classified into Campylobacter spp. The identified isolates were later affirmed by polymerase chain reaction using primers that were designed to locate hipO genes in C. jejuni and glyA in C. coli.Results:Of the total 150 examined samples of raw milk and soft cheese samples; 37 (24.6%) samples were contaminated with Campylobacter spp. C. jejuni was dominating in this study in 20%, 14%, and 8% of the examined raw milk, kareish cheese, and yoghurt samples, respectively. No sample harbored C. coli.Conclusion:Campylobacter spp. could be detected in 24.6% of the investigated samples. C. jejuni isolated from 14% of the total tested samples, while C. coli could not be detected from the examined samples. Campylobacter spp. is rampant in the areas of poor hygienic conditions making products made from raw milk of public health hazard.

Detection of &lt;italic&gt;L. Monocytogenes&lt;/italic&gt; in Enrichment Cultures by Immunoseparation and Immunosensors

There is a need to identify the presence of bacterial pathogens in foods earlier than it is currently carried out. At present, pre-enrichment culture followed by selective agar plating is standard microbiological methods applied to detect Listeria monocytogenes and other bacterial pathogens with zero tolerance in food products. PCR and biosensor methods may shorten the time required to individuate contamination by L. monocytogenes in a pre-enrichment culture. In this paper, a protein chip immunosensor with a sensitivity of 100 CFU/mL was developed for Listeria spp. detection. The method provides a ten-fold increase in sensitivity compared with published work on bacteria immunosensing coupled to fluorescence detection. When 40 mL of Listeria spp. pre-enrichment culture were processed by immunoseparation, the limit of detection was lowered to 2.5 CFU/mL. The results obtained from the real food samples were confirmed by qPCR. We also showed the potential for multiplexing of the protein chip method demonstrating the selective detection of Listeria monocytogenes, Staphylococcus aureus, Salmonella spp., Escherichia coli, and Campylobacter spp. A future development is the integration into a system for rapid screening of pathogens contaminating food productions.

A four‐quadrant sequential streak technique to evaluate Campylobacter selective broths for suppressing background flora in broiler carcass rinses

AbstractA semi‐quantitative ecometric technique was used to evaluate efficacy of selective culture media. It involved a standardized chronological streaking technique, leading to ever‐decreasing number of colonies. The objective was to evaluate the efficacy of this technique (four‐quandrant sequential streak [FQS]) with two commonly used Campylobacter broths (Bolton's and Tecra) with whole carcass rinses of post‐pick broilers (n = 30) obtained from a commercial processing plant. Ten ?L from each sample type was streaked (five individual streak lines) onto one quarter of a Campy‐cefex agar plate and sequentially into the next three quadrants. Growth of extraneous bacteria was expressed as an absolute growth index (AGI). A significant (P &lt; 0.05) difference in background microflora suppression was observed using this procedure. A positive correlation between decreasing levels of background microflora within the broths was observed as the AGI declined. FQS can be used for rapid semi‐quantitative estimation of an enrichment broth's efficacy.Practical applicationsThe heavy presence of extraneous background microorganisms on a selective agar plate is a serious deterrent to the accurate detection of a target organism. This study confirmed sequential streaking as an appropriate and easily applied method to evaluate the relative efficiency of selective enrichment broths for Campylobacter in the suppression of background microflora on selective plates. The four‐quadrant sequential streak (FQS) ecometric technique is an inexpensive, rapid, semi‐quantitative method to evaluate the effectiveness of various selective enrichment broths.