Rapid Detection of Listeria in Ice Cream in 13 Hours Using the Roka Listeria Detection Assay

Abstract Background: Listeria contamination is a major concern in the ice cream industry; therefore, early and accurate detection is vital. Current detection methods require about a 24 h enrichment period for detection. Objective: Enhance the early detection of Listeria in ice cream using the highly sensitive isothermal ribosomal RNA-based Roka/Atlas Listeria Detection Assay. Methods: The R2 Medium was developed for Listeria enrichment by Molecular Epidemiology, Inc. (Seattle, WA). Comparative growth curve studies were performed on the new R2 Medium for Listeria and the currently validated media for the Roka Listeria Detection Assay. Subsequently, a method comparison between the Roka Listeria Detection Assay and the U.S. Food and Drug Administration’s (FDA) Bacteriological Analytical Manual (BAM) Chapter 10 reference method on ice cream was carried out. Results: The R2 Medium supports the growth of L. monocytogenes better than Buffered Listeria Enrichment Broth, Demi-Fraser broth, and Modified University of Vermont Broth, as indicated by the faster growth rate of the organism. When used as an enrichment medium in a method comparison study of ice cream, the results showed that R2 Medium–enriched samples tested with the Roka Listeria Detection Assay gave an equivalent performance compared with the 24 h FDA-BAM reference method at 10 and 18 h post-enrichment for Listeria. Conclusions: The results from this study indicate that the new R2 Medium and the highly sensitive Roka Listeria Detection Assay allowed for the rapid detection of Listeria species in ice cream in 13 h. Highlights: The Roka Listeria Detection Assay, in conjunction with a new media formulation (R2 Medium), allowed for the early detection of Listeria in ice cream and may be applied in other food matrixes and environmental samples.

Download Full-text

Early detection of Pseudomonas aeruginosa and Escherichia coli. using zinc tetraphenylporphyrin

European Journal of Public Health ◽

10.1093/eurpub/ckaa166.191 ◽

2020 ◽

Vol 30 (Supplement_5) ◽

Author(s):

A Sharma ◽

S Kumar ◽

S Handa ◽

S K Pandey ◽

A P Bhondekar

Keyword(s):

Escherichia Coli ◽

Pseudomonas Aeruginosa ◽

Early Detection ◽

Ambient Temperature ◽

Rapid Detection ◽

Unmet Need ◽

Complex Mixture ◽

Detection Methods ◽

Investigation Methods ◽

Tetraphenyl Porphyrin

Abstract The sensory characteristics of food are considerably effected by the metabolic processes of various micro-organisms in the food stored in the field or at ambient temperature. Also, this microbial contamination can pose serious health hazards to public health. Chemical analysis of the complex mixture of volatiles produced during bacterial growth and investigation methods of these microorganisms presents a big challenge. There remains major unmet need to shorten and improve detection methods. Therefore, early detection of the microorganisms will open many frontiers for quality control in the foodstuffs industry. Accordingly, the aim of this study was to assess the feasibility and performance of chemoreceptive sensors for the rapid detection of bacterial pathogens, specifically Pseudomonas aeruginosa and Escherichia coli. In Uv/vis study, zinc tetraphenyl porphyrin solutions (in DMF) was tested with various volatile compounds, such as propanal, hexanal and heptanal which are commonly found to be released during the growth of bacteria. These sensors were used to detect the bacterial odours of two pathogenic species (E.coli and P.aeruginosa) during their growth cycle at 4 °C and ambient temperature. Hypochromic shifts in Uv/vis and hydrogen bonding in FT-IR studies confirmed the interaction between the volatiles and porphyrin. The porphyrin used detected the presence of microorganisms after 12 hrs incubation and showed more sensitivity for volatiles released during aerobic activity P. aeruginosa as compared to E. coli at 4 °C and ambient temperature. Zinc tetraphenyl porphyrin based chemoreceptive membranes has been proved successful for the detection of P. aeruginosa. Hence, the present study proves wide scope of improvement over current laboratory techniques for the detection of pathogens in terms of speed, ease of use, and cost. Key messages The developed technique allows rapid detection of spoiled food. Chemoreceptive property of porphyrin has been exploited for the early detection of bacteria.

Download Full-text

Comparison of FoodChek E. coli Test and AOAC Research Institute Performance Tested Method 010603 for Detection of E. coli O157 in Raw Ground Beef

Journal of AOAC International ◽

10.1093/jaoac/93.3.922 ◽

2010 ◽

Vol 93 (3) ◽

pp. 922-927 ◽

Cited By ~ 2

Author(s):

Richard J Flanagan ◽

Gabriela Martinez

Keyword(s):

Magnetic Nanoparticle ◽

Raw Materials ◽

Detection System ◽

Detection Threshold ◽

Reference Method ◽

Superparamagnetic Nanoparticles ◽

E Coli ◽

Detection Assay ◽

Highly Sensitive ◽

Research Institute

Abstract The FoodChek E. coli O157 assay [AOAC Research Institute (RI) Performance Tested Method (PTM) 060902] is a rapid detection system that incorporates the use of antibody-coated superparamagnetic nanoparticles in a lateral flow immunoassay format. The system comprises a commercially available enrichment medium, a magnetic nanoparticle immunoassay, and an automated reader for detection. Assay detection threshold is improved relative to traditional immunoassays through use of a magnetic nanoparticle label and a highly sensitive magnetic particle detector. FoodChek E. coli O157 is a reintroduction of the previously certified AOAC PTM 010603. The original assay was evaluated and approved in internal and independent laboratory studies. Vacci-Test Corp. has contracted with the original supplier of the PTM to remanufacture the test under identical conditions and with identical raw materials. This report is intended to show that FoodChek E. coli is identical in performance to the previously approved PTM. The results showed no difference for the parameters evaluated. Three kit lots along with three lots of media and media supplement were compared in lot-to-lot and stability testing. The results indicated no difference in performance across the three lots. The results showed sensitivity of >99 and a specificity rate of >98 for the FoodChek method and a significantly higher sensitivity than the reference method.

Download Full-text

Application of Sample6 DETECT™ HT/L Kit for the Detection of Listeria in Mixed Leafy Greens

Journal of AOAC International ◽

10.5740/jaoacint.18-0238 ◽

2020 ◽

Vol 103 (1) ◽

pp. 156-160 ◽

Cited By ~ 1

Author(s):

Elba Veronica Arias-Rios ◽

Kristina Tenney ◽

Tam Mai ◽

Ruth Marie Cantera ◽

Brandon Selover ◽

...

Keyword(s):

Early Detection ◽

Detection System ◽

Method Comparison ◽

Package Insert ◽

Reference Method ◽

Leafy Greens ◽

Plate Reader ◽

Centrifugation Step ◽

Detection Chamber ◽

Food Matrices

Abstract Background: Early and accurate detection of Listeria in foods is vital. Current methods require 24 h enrichment for detection. Objective: This study aimed to demonstrate enhanced early detection of Listeria in mixed leafy greens using Sample6 DETECT™ HT/L, a phage-based detection system. Methods: A method comparison between the reference method (U.S. Food and Drug Administration Bacteriological Analytical Manual Chapter 10) for the detection of Listeria spp. and the Sample6 DETECT HT/L using a new proprietary R2 Medium was performed in mixed leafy greens. Results: Using the R2 Medium enrichment with Sample6 DETECT HT/L, detection of L. innocua was possible at 12 h (with a centrifugation step), and L. monocytogenes was detected by 18 h, with equivalent performance as the 24 h enrichments using the reference method detection. The Sample6 DETECT HT/L gave an equivalent performance for L. innocua at 15 h as the reference method at 24 h. Detection was accomplished by the addition of reagents in the kit, following the package insert, and reading results in a detection chamber using a 96-well plate reader that detects a fluorescent signal. Conclusions: Results indicate the new R2 Medium and Sample6 DETECT HT/L allowed for earlier detection of Listeria spp. in mixed leafy greens. Highlights: Sample6 DETECT HT/L with the new R2 Medium allowed the early detection of Listeria spp. and may be applied in other food matrices and environmental samples.

Download Full-text

Rapid Molecular Detection Methods for Arboviruses of Livestock of Importance to Northern Europe

Journal of Biomedicine and Biotechnology ◽

10.1155/2012/719402 ◽

2012 ◽

Vol 2012 ◽

pp. 1-18 ◽

Cited By ~ 13

Author(s):

Nicholas Johnson ◽

Katja Voller ◽

L. Paul Phipps ◽

Karen Mansfield ◽

Anthony R. Fooks

Keyword(s):

Early Detection ◽

Rapid Detection ◽

Molecular Detection ◽

Emerging Infectious Diseases ◽

Emerging Diseases ◽

Detection Methods ◽

Northern Europe ◽

Human Pathogens ◽

Critical Feature ◽

The Past

Arthropod-borne viruses (arboviruses) have been responsible for some of the most explosive epidemics of emerging infectious diseases over the past decade. Their impact on both human and livestock populations has been dramatic. The early detection either through surveillance or diagnosis of virus will be a critical feature in responding and resolving the emergence of such epidemics in the future. Although some of the most important emerging arboviruses are human pathogens, this paper aims to highlight those diseases that primarily affect livestock, although many are zoonotic and some occasionally cause human mortality. This paper also highlights the molecular detection methods specific to each virus and identifies those emerging diseases for which a rapid detection methods are not yet developed.

Download Full-text

Application of an Environmental Phage-Based Assay (Sample6 Detect HT/L) for the Detection of Listeria spp. in Ice Cream

Journal of AOAC International ◽

10.5740/jaoacint.18-0253 ◽

2019 ◽

Vol 102 (4) ◽

pp. 1132-1137 ◽

Cited By ~ 2

Author(s):

Elba Veronica Arias-Rios ◽

Kristina Tenney ◽

Tam Mai ◽

Sam Anderson ◽

Ruth Marie Cantera ◽

...

Keyword(s):

Listeria Monocytogenes ◽

Early Detection ◽

Incubation Time ◽

Environmental Samples ◽

Dairy Products ◽

Reference Method ◽

Ice Cream ◽

Time Points ◽

Test Kit ◽

Financial Losses

Abstract Background: Dairy products are common sources of Listeria outbreaks, and early detection of the pathogen is critical to prevent outbreaks of illnesses and financial losses for dairy producers. Objective: This study aimed to evaluate Sample6 Detect HT/L for effective detection of Listeria monocytogenes and L. innocua in ice cream. Methods: Performance of the Sample6 DETECT HT/L was compared with U.S. Food and Drug Administration (FDA) Bacteriological Analytical Manual (BAM) Chapter 10 method for detection of Listeria spp. in ice cream using an unpaired study design. Results: R2-enriched samples tested with Sample6 Detect HT/L performed as well as the reference method at all time points tested from 15 to 24 h. R2 is a proprietary blend for use with the test kit that helps with early detection. All the dPODC values (Sample6 Detect HT/L presumptive and confirmed results) equaled zero, indicating 100% concordance between the methods. Both Sample6 Detect HT/L and FDA BAM results showed low dPODC values, with confidence intervals indicating no significant differences between Sample6 Detect HT/L and reference method results. Conclusions: Sample6 Detect HT/L is suitable to detect Listeria spp. in ice cream, even with a 12 h enrichment. Sample6 Detect HT/L demonstrated equivalent detection of L. monocytogenes and L. innocua from R2-enriched samples as expected with 15 and 18 h enrichment when compared with the 24 h FDA BAM method for L. monocytogenes. Highlights: These results indicate that Sample6 Detect HT/L, primarily developed for environmental samples, can be used to detect Listeria spp. in ice cream with less incubation time, resulting in faster detection.

Download Full-text

A family with pheochromocytoma-paraganglioma inherited tumour syndrome

Nuklearmedizin ◽

10.3413/nukmed-0755-15-07 ◽

2016 ◽

Vol 55 (01) ◽

pp. 34-40 ◽

Cited By ~ 3

Author(s):

P. Zschieschang ◽

V. Prasad ◽

D. Moskopp ◽

B. Knie ◽

M. Plotkin

Keyword(s):

Early Detection ◽

Neck Region ◽

Hereditary Disease ◽

Head And Neck Region ◽

Pet Ct ◽

Highly Sensitive ◽

Hereditary Pheochromocytoma ◽

Genetically Determined ◽

Mass Lesions ◽

Pet Ct Scan

SummaryAim: Hereditary pheochromocytoma-paraganglioma syndromes are characterized by multiple pheochromocytomas (PCC) and paragangliomas (PGLs), inherited in an autosomal dominant manner. Early detection and removal of tumours may prevent or minimize complications related to mass effects and malignant transformation. Having confirmed the diagnosis, it is important to localize the tumours and reveal their extent preoperatively. This study aimed to introduce 18F-DOPA PET/CT as a highly sensitive noninvasive diagnostic tool for early detection of mass lesions in patients with pheochromocytoma-paraganglioma inherited tumour syndrome and to report about its impact on patient management. Patients, methods: We are currently supervising one of the largest documented families in Germany with genetically determined SDHD gene mutation. We performed 18F-DOPA PET/CT in order to detect tumours in asymptomatic gene carriers and enable subsequent surgical therapy. Results: In seven patients undergoing 12 18F-DOPA PET/CT scans 17 lesions have been detected. Three of these lesions, located in the head and neck region, have had no morphologic correlate in CT and one had also no morphologic correlate in MRI. Of the six histologically analyzed lesions five have been tumors (PGL or PCC) and one has been a nodular hyperplasia. This means the 18F-DOPA PET/CT scan in our study group had a sensitivity of 83%. 18F-DOPA PET/CT investigations lead to change in the management in 5/7 studied patients (70%). Conclusion: The benefits of PET/ CT in detection of pheochromocytoma and paraganglioma are well documented, but we are the first to use this technique for screening of a rare hereditary disease (estimated prevalence 0.3/100 000).

Download Full-text

Development of an antigen-ELISA and a colloidal gold–based immunochromatographic strip based on monoclonal antibodies for detection of avian influenza A(H5) viruses

Journal of Veterinary Diagnostic Investigation ◽

10.1177/10406387211027538 ◽

2021 ◽

pp. 104063872110275

Author(s):

Yixin Xiao ◽

Fan Yang ◽

Fumin Liu ◽

Linfang Cheng ◽

Hangping Yao ◽

...

Keyword(s):

Avian Influenza ◽

Disease Virus ◽

Colloidal Gold ◽

Rapid Detection ◽

Influenza A ◽

Field Investigation ◽

Cross Reactivity ◽

Detection Methods ◽

Immunochromatographic Strip ◽

Antigen Elisa

Avian influenza A(H5) viruses (avian IAVs) pose a major threat to the economy and public health. We developed an antigen-ELISA (ag-ELISA) and a colloidal gold–based immunochromatographic strip for the rapid detection of avian A(H5) viruses. Both detection methods displayed no cross-reactivity with other viruses (e.g., other avian IAVs, infectious bursal disease virus, Newcastle disease virus, infectious bronchitis virus, avian paramyxovirus). The ag-ELISA was sensitive down to 0.5 hemagglutinin (HA) units/100 µL of avian A(H5) viruses and 7.5 ng/mL of purified H5 HA proteins. The immunochromatographic strip was sensitive down to 1 HA unit/100 µL of avian A(H5) viruses. Both detection methods exhibited good reproducibility with CVs < 10%. For 200 random poultry samples, the sensitivity and specificity of the ag-ELISA were 92.6% and 98.8%, respectively, and for test strips were 88.9% and 98.3%, respectively. Both detection methods displayed high specificity, sensitivity, and stability, making them suitable for rapid detection and field investigation of avian A(H5) viruses.

Download Full-text

Detection by real-time quaking-induced conversion (RT-QuIC), ELISA, and IHC of chronic wasting disease prion in lymph nodes from Pennsylvania white-tailed deer with specific PRNP genotypes

Journal of Veterinary Diagnostic Investigation ◽

10.1177/10406387211021411 ◽

2021 ◽

pp. 104063872110214

Author(s):

Deepanker Tewari ◽

David Steward ◽

Melinda Fasnacht ◽

Julia Livengood

Keyword(s):

Real Time ◽

Disease Susceptibility ◽

Chronic Wasting Disease ◽

Low Frequency ◽

The United States ◽

Detection Methods ◽

Spongiform Encephalopathy ◽

Wasting Disease ◽

Diagnostic Laboratory ◽

Highly Sensitive

Chronic wasting disease (CWD) is a prion-mediated, transmissible disease of cervids, including deer ( Odocoileus spp.), which is characterized by spongiform encephalopathy and death of the prion-infected animals. Official surveillance in the United States using immunohistochemistry (IHC) and ELISA entails the laborious collection of lymphoid and/or brainstem tissue after death. New, highly sensitive prion detection methods, such as real-time quaking-induced conversion (RT-QuIC), have shown promise in detecting abnormal prions from both antemortem and postmortem specimens. We compared RT-QuIC with ELISA and IHC for CWD detection utilizing deer retropharyngeal lymph node (RLN) tissues in a diagnostic laboratory setting. The RLNs were collected postmortem from hunter-harvested animals. RT-QuIC showed 100% sensitivity and specificity for 50 deer RLN (35 positive by both IHC and ELISA, 15 negative) included in our study. All deer were also genotyped for PRNP polymorphism. Most deer were homozygous at codons 95, 96, 116, and 226 (QQ/GG/AA/QQ genotype, with frequency 0.86), which are the codons implicated in disease susceptibility. Heterozygosity was noticed in Pennsylvania deer, albeit at a very low frequency, for codons 95GS (0.06) and 96QH (0.08), but deer with these genotypes were still found to be CWD prion-infected.

Download Full-text

Early Detection Methods for Silicosis in Australia and Internationally: A Review of the Literature

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18158123 ◽

2021 ◽

Vol 18 (15) ◽

pp. 8123

Author(s):

Emma K. Austin ◽

Carole James ◽

John Tessier

Keyword(s):

Early Detection ◽

Literature Review ◽

Detection Method ◽

Detection Methods ◽

X Rays ◽

Review Of The Literature ◽

Occupational Lung Disease ◽

Work Related ◽

Growing Body ◽

Future Work

Pneumoconiosis, or occupational lung disease, is one of the world’s most prevalent work-related diseases. Silicosis, a type of pneumoconiosis, is caused by inhaling respirable crystalline silica (RCS) dust. Although silicosis can be fatal, it is completely preventable. Hundreds of thousands of workers globally are at risk of being exposed to RCS at the workplace from various activities in many industries. Currently, in Australia and internationally, there are a range of methods used for the respiratory surveillance of workers exposed to RCS. These methods include health and exposure questionnaires, spirometry, chest X-rays, and HRCT. However, these methods predominantly do not detect the disease until it has significantly progressed. For this reason, there is a growing body of research investigating early detection methods for silicosis, particularly biomarkers. This literature review summarises the research to date on early detection methods for silicosis and makes recommendations for future work in this area. Findings from this review conclude that there is a critical need for an early detection method for silicosis, however, further laboratory- and field-based research is required.

Download Full-text