Effect of the Bioprotective Properties of Lactic Acid Bacteria Strains on Quality and Safety of Feta Cheese Stored under Different Conditions.

Lately, the inclusion of additional lactic acid bacteria (LAB) strains to cheeses is becoming more popular since they can affect cheese's nutritional, technological, and sensory properties, as well as increase the product's safety. This work studied the effect of Lactiplantibacillus pentosus L33 and Lactiplantibacillus plantarum L125 free cells and supernatants on feta cheese quality and Listeria monocytogenes fate. In addition, rapid and non-invasive techniques such as Fourier transform infrared (FTIR) and multispectral imaging (MSI) analysis were used to classify the cheese samples based on their sensory attributes. Slices of feta cheese were contaminated with 3 log CFU/g of L. monocytogenes, and then the cheese slices were sprayed with (i) free cells of the two strains of the lactic acid bacteria (LAB) in co-culture (F, ~5 log CFU/g), (ii) supernatant of the LAB co-culture (S) and control (C, UHT milk) or wrapped with Na-alginate edible films containing the pellet (cells, FF) or the supernatant (SF) of the LAB strains. Subsequently, samples were stored in air, in brine, or in vacuum at 4 and 10 °C. During storage, microbiological counts, pH, and water activity (aw) were monitored while sensory assessment was conducted. Also, in every sampling point, spectral data were acquired by means of FTIR and MSI techniques. Results showed that the initial microbial population of Feta was ca. 7.6 log CFU/g and consisted of LAB (>7 log CFU/g) and yeast molds in lower levels, while no Enterobacteriaceae were detected. During aerobic, brine, and vacuum storage for both temperatures, pathogen population was slightly postponed for S and F samples and reached lower levels compared to the C ones. The yeast mold population was slightly delayed in brine and vacuum packaging. For aerobic storage at 4 °C, an elongation in the shelf life of F samples by 4 days was observed compared to C and S samples. At 10 °C, the shelf life of both F and S samples was extended by 13 days compared to C samples. FTIR and MSI analyses provided reliable estimations of feta quality using the PLS-DA method, with total accuracy (%) ranging from 65.26 to 84.31 and 60.43 to 89.12, respectively. In conclusion, the application of bioprotective LAB strains can result in the extension of feta's shelf life and provide a mild antimicrobial action against L. monocytogenes and spoilage microbiota. Furthermore, the findings of this study validate the effectiveness of FTIR and MSI techniques, in tandem with data analytics, for the rapid assessment of the quality of feta samples.

Development of a Multiplexed Sphingolipids Method for Diagnosis of Inborn Errors of Ceramide Metabolism.

BACKGROUND: Sphingolipids play a crucial role in cellular functions and are essential components of cell membranes, signaling molecules, and lipid metabolism. In particular, ceramide is a key intermediate in sphingolipid metabolism and defects in ceramide metabolism can lead to various inborn errors of metabolism, making ceramides important targets for clinical screening and diagnosis. Detecting altered concentration patterns of sphingolipids is desirable for distinguishing related inborn errors of metabolism for diagnosis and treatment monitoring. METHODS: We developed a liquid chromatography-tandem mass spectrometry method with a pathway-oriented approach to focus on sphingolipids involved in ceramide metabolism. A total of 47 sphingolipids bearing different head groups and side chains were targeted. Precision/reproducibility, linearity, and spike recovery extraction efficiency tests were performed on plasma and serum samples from confirmed cases of sphingolipidosis. RESULTS: Linearity of the method showed the coefficient of determination (r2) for all standards to be >0.99 with a slope of 1.00 ± 0.01. Intra- and interday reproducibility of standards spiked into plasma and serum revealed a coefficient of variation <20%. Spike and recovery assessment showed recovery values of 80%-120% for all standards. Altered levels of sphingolipids from patients with hereditary sensory and autonomic neuropathy caused by pathogenic variants in SPTLC2 and hypomyelinating leukodystrophy related to variants in DEGS1 were detected, in agreement with trends reported in earlier studies confirming the utility of this pathway-centric method. CONCLUSIONS: This method can serve as a useful tool to simultaneously monitor sphingolipids, enabling screening and diagnosis of inborn errors of ceramide metabolism.

Culture-Free Whole Genome Sequencing of Mycobacterium tuberculosis Using Ligand-Mediated Bead Enrichment Method.

Background: Direct whole genome sequencing (WGS) of Mycobacterium tuberculosis (Mtb) can be used as a tool to study drug resistance, mixed infections, and within-host diversity. However, WGS is challenging to obtain from clinical samples due to low number of bacilli against a high background. Methods: We prospectively collected 34 samples (sputum, n = 17; bronchoalveolar lavage, n = 13; and pus, n = 4) from patients with active tuberculosis (TB). Prior to DNA extraction, we used a ligand-mediated magnetic bead method to enrich Mtb from clinical samples and performed WGS on Illumina platform. Results: Mtb was definitively identified based on WGS from 88.2% (30/34) of the samples, of which 35.3% (12/34) were smear negative. The overall median genome coverage was 15.2% (interquartile range [IQR], 7.7%-28.2%). There was a positive correlation between load of bacilli on smears and genome coverage (P < .001). We detected 58 genes listed in the World Health Organization mutation catalogue in each positive sample (median coverage, 85% [IQR, 61%-94%]), enabling the identification of mutations missed by routine diagnostics. Mutations causing resistance to rifampicin, isoniazid, streptomycin, and ethambutol were detected in 5 of 34 (14.7%) samples, including the rpoB S441A mutation that confers resistance to rifampicin, which is not covered by Xpert MTB/RIF. Conclusions: We demonstrate the feasibility of magnetic bead-based enrichment for culture-free WGS of Mtb from clinical specimens, including smear-negative samples. This approach can also be integrated with low-cost sequencing workflows such as targeted sequencing for rapid detection of Mtb and drug resistance.

Monitoring the Bioprotective Potential of Lactiplantibacillus pentosus Culture on Pathogen Survival and the Shelf-Life of Fresh Ready-to-Eat Salads Stored under Modified Atmosphere Packaging.

Globally, fresh vegetables or minimally processed salads have been implicated in several foodborne disease outbreaks. This work studied the effect of Lactiplantibacillus pentosus FMCC-B281 cells (F) and its supernatant (S) on spoilage and on the fate of Listeria monocytogenes and Escherichia coli O157:H7 on fresh-cut ready-to-eat (RTE) salads during storage. Also, Fourier transform infrared (FTIR) and multispectral imaging (MSI) analysis were used as rapid and non-destructive techniques to estimate the microbiological status of the samples. Fresh romaine lettuce, rocket cabbage, and white cabbage were used in the present study and were inoculated with L. pentosus and the two pathogens. The strains were grown at 37 °C for 24 h in MRS and BHI broths, respectively, and then were centrifuged to collect the supernatant and the pellet (cells). Cells (F, ~5 log CFU/g), the supernatant (S), and a control (C, broth) were used to spray the leaves of each fresh vegetable that had been previously contaminated (sprayed) with the pathogen (3 log CFU/g). Subsequently, the salads were packed under modified atmosphere packaging (10%CO2/10%O2/80%N2) and stored at 4 and 10 °C until spoilage. During storage, microbiological counts and pH were monitored in parallel with FTIR and MSI analyses. The results showed that during storage, the population of the pathogens increased for lettuce and rocket independent of the treatment. For cabbage, pathogen populations remained stable throughout storage. Regarding the spoilage microbiota, the Pseudomonas population was lower in the F samples, while no differences in the populations of Enterobacteriaceae and yeasts/molds were observed for the C, F, and S samples stored at 4 °C. According to sensory evaluation, the shelf-life was shorter for the control samples in contrast to the S and F samples, where their shelf-life was elongated by 1-2 days. Initial pH values were ca. 6.0 for the three leafy vegetables. An increase in the pH of ca. 0.5 values was recorded until the end of storage at both temperatures for all cases of leafy vegetables. FTIR and MSI analyses did not satisfactorily lead to the estimation of the microbiological quality of salads. In conclusion, the applied bioprotective strain (L. pentosus) can elongate the shelf-life of the RTE salads without an effect on pathogen growth.

Two-Month Consumption of Orange Juice Enriched with Vitamin D3 and Probiotics Decreases Body Weight, Insulin Resistance, Blood Lipids, and Arterial Blood Pressure in High-Cardiometabolic-Risk Patients on a Westernized Type Diet: Results from a Randomized Clinical Trial.

This study examined the effects of orange juice (OJ) supplemented with vitamin D3 (2000 IU) and probiotics (Lacticaseibacillus casei Shirota and Lacticaseibacillus rhamnosus GG, 108 cfu/mL) on cardiometabolic risk factors in overweight and obese adults following a Westernized-type diet. Fifty-three high-risk individuals were randomly assigned to one of two groups. Over 8 weeks, one group consumed a vitamin D3 and probiotic-enriched OJ and the other regular OJ (control). Diets remained unchanged and were documented through food diaries. Measures of metabolic and inflammatory markers and blood pressure were measured at the start and end of the study. Post-intervention, the enriched OJ group showed the following significant metabolic improvements (without changes in triglycerides, inflammation, or central blood pressure): reduced fasting insulin, peripheral blood pressure, body weight (-1.4 kg 95% CI: -2.4, -0.4), energy (-270 kcal 95% CI: -553.2, -13.7), macronutrient (dietary fat -238 kcal 95% CI: -11.9, -1.0; carbohydrates -155 kcal 95% CI: -282.4, -27.3; sugars -16.1 g 95% CI: -11.9, -1.0) intake, and better lipid profiles (total cholesterol -10.3 mg/dL 95% CI: -21.4, 0.9; LDL-C -7 mg/dL 95% CI: -13.5, -0.5). The enriched OJ led to weight loss, less energy/macronutrient consumption, improved lipid profiles, and increased insulin sensitivity after 8 weeks in those following a Westernized diet, thus indicating potential benefits for cardiometabolic risk. This study was a part of FunJuice-T2EDK-01922, which was funded by the EU Regional Development Fund and Greek National Resources.

Microbiome mapping in beef processing reveals safety-relevant variations in microbial diversity and genomic features.

The microbiome of surfaces along the beef processing chain represents a critical nexus where microbial ecosystems play a pivotal role in meat quality and safety of end products. This study offers a comprehensive analysis of the microbiome along beef processing using whole metagenomics with a particular focus on antimicrobial resistance and virulence-associated genes distribution. Our findings highlighted that microbial communities change dynamically in the different steps along beef processing chain, influenced by the specific conditions of each micro-environment. Brochothrix thermosphacta, Carnobacterium maltaromaticum, Pseudomonas fragi, Psychrobacter cryohalolentis and Psychrobacter immobilis were identified as the key species that characterize beef processing environments. Carcass samples and slaughterhouse surfaces exhibited a high abundance of antibiotic resistance genes (ARGs), mainly belonging to aminoglycosides, ß-lactams, amphenicols, sulfonamides and tetracyclines antibiotic classes, also localized on mobile elements, suggesting the possibility to be transmitted to human pathogens. We also evaluated how the initial microbial contamination of raw beef changes in response to storage conditions, showing different species prevailing according to the type of packaging employed. We identified several genes leading to the production of spoilage-associated compounds, and highlighted the different genomic potential selected by the storage conditions. Our results suggested that surfaces in beef processing environments represent a hotspot for beef contamination and evidenced that mapping the resident microbiome in these environments may help in reducing meat microbial contamination, increasing shelf-life, and finally contributing to food waste restraint.

Comparison of the diagnostic yield of rapid versus non-rapid onsite evaluation in endoscopic ultrasound-guided fine-needle aspiration cytology of solid pancreatic lesions.

Background: The role of rapid on-site evaluation (ROSE) for endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) of pancreatic lesions is debatable. In this study, we aimed to compare the diagnostic yield of ROSE vs. non-ROSE in solid pancreatic lesions. Methods: This retrospective single-center study included patients undergoing EUS-FNA of solid pancreatic lesions from 2019-2021. Patients with cystic lesions, those undergoing fine-needle core biopsy, those undergoing repeat procedures, and patients with non-diagnostic smears with less than 6-month follow up were excluded. The diagnostic yield, need for repeat procedures and number of passes required with and without ROSE were analyzed in these patients. Results: Of the 111 patients included, 56 underwent ROSE. The majority of lesions were malignant in both groups (79.6% ROSE vs. 75% non-ROSE). The diagnostic yield was 96.4% in the ROSE group and 94.5% in the non-ROSE group. Repeat samples were needed in 1 ROSE and 2 non-ROSE patients. The median number of passes made was significantly fewer in the ROSE group (3.5, interquartile range - 3,4) compared with the non-ROSE group (4, interquartile range - 3,5) P=0.01. However, the frequency of procedure-related complications was similar in both groups. Conclusion: The utilization of ROSE during EUS-FNA of solid pancreatic lesions does not affect the diagnostic yield or the need for repeat samples, but reduces the number of passes needed for acquiring samples.

The Effect of the PhoP/PhoQ System on the Regulation of Multi-Stress Adaptation Induced by Acid Stress in Salmonella Typhimurium.

Acidic stress in beef cattle slaughtering abattoirs can induce the acid adaptation response of in-plant contaminated Salmonella. This may further lead to multiple resistance responses threatening public health. Therefore, the acid, heat, osmotic and antibiotic resistances of Salmonella typhimurium (ATCC14028) were evaluated after a 90 min adaption in a pH = 5.4 "mild acid" Luria-Bertani medium. Differences in such resistances were also determined between the ∆phoP mutant and wild-type Salmonella strains to confirm the contribution of the PhoP/PhoQ system. The transcriptomic differences between the acid-adapted and ∆phoP strain were compared to explore the role of the PhoP/Q two-component system in regulating multi-stress resistance. Acid adaptation was found to increase the viability of Salmonella to lethal acid, heat and hyperosmotic treatments. In particular, acid adaptation significantly increased the resistance of Salmonella typhimurium to Polymyxin B, and such resistance can last for 21 days when the adapted strain was stored in meat extract medium at 4 °C. Transcriptomics analysis revealed 178 up-regulated and 274 down-regulated genes in the ∆phoP strain. The Salmonella infection, cationic antimicrobial peptide (CAMP) resistance, quorum sensing and two-component system pathways were down-regulated, while the bacterial tricarboxylic acid cycle pathways were up-regulated. Transcriptomics and RT-qPCR analyses revealed that the deletion of the phoP gene resulted in the down-regulation of the expression of genes related to lipid A modification and efflux pumps. These changes in the gene expression result in the change in net negative charge and the mobility of the cell membrane, resulting in enhanced CAMP resistance. The confirmation of multiple stress resistance under acid adaptation and the transcriptomic study in the current study may provide valuable information for the control of multiple stress resistance and meat safety.

Seabream Quality Monitoring Throughout the Supply Chain Using a Portable Multispectral Imaging Device.

Monitoring food quality throughout the supply chain in a rapid and cost-effective way allows on-time decision-making, reducing food waste, and increasing sustainability. A portable multispectral imaging sensor was used for the rapid prediction of microbiological quality of fish fillets. Seabream fillets, packaged either in aerobic or vacuum conditions, were collected from both aquaculture and retail stores, while images were also acquired both from the skin and the flesh side of the fish fillets. In parallel to image acquisition, the microbial quality was also estimated for each fish fillet. The data were used for the training of predictive artificial neural network (ANN) models for the estimation of total aerobic counts (TACs). Models were built separately for fish parts (i.e., skin, flesh) and packaging conditions and were validated using two approaches (i.e., validation with data partitioning and external validation using samples from retail stores). The performance of the ANN models for the validation set with data partitioning was similar for the data collected from the flesh (RMSE = 0.402-0.547) and the skin side (RMSE = 0.500-0.533) of the fish fillets. Similar performance also was obtained from validation of the models of the different packaging conditions (i.e., aerobic, vacuum). The prediction capability of the models combining both air and vacuum packaged samples (RMSE = 0.531) was slightly lower compared to the models trained and validated per packaging condition, individually (RMSE = 0.510, 0.516 in air and vacuum, respectively). The models tested with unknown samples (i.e., fish fillets from retail stores-external validation) showed poorer performance (RMSE = 1.061-1.414) compared to the models validated with data partitioning (RMSE = 0.402-0.547). Multispectral imaging sensor appeared to be efficient for the rapid assessment of the microbiological quality of fish fillets for all the different cases evaluated. Hence, these outcomes could be beneficial not only for the industry and food operators but also for the authorities and consumers.

Bile Culture May Guide Antibiotic Stewardship in Acute Bacterial Cholangitis.

BACKGROUND: Bile cultures are often sent with blood cultures in patients with acute bacterial cholangitis. AIMS: To assess the yield of blood and bile cultures in patients with cholangitis and the clinical utility of bile cultures in guiding therapy. METHODS: All patients diagnosed with cholangitis, based on the Tokyo 2013/2018 guidelines were recruited retrospectively over ten years. The clinical and investigation details were recorded. The results of bile and blood cultures including antibiotic sensitivity patterns were noted. The concordance of microorganisms grown in blood and bile cultures and their sensitivity pattern were assessed. RESULTS: A total of 1063 patients with cholangitis were included. Their mean age was 52.7 ± 14 years and 65.4% were males. Blood cultures were positive in 372 (35%) patients. Bile culture was performed in 384 patients with 84.4% being positive, which was significantly higher than the yield of blood culture (p < 0.001). Polymicrobial growth was more in bile (59.3%) than in blood cultures (13.5%, p < 0.001). E.coli, Klebsiella, Enterococcus and Pseudomonas were the four most common organisms isolated from both blood and bile. Extended spectrum betalactamase producing organisms were isolated in 57.7% and 58.8% of positive blood and bile cultures, respectively. Among 127 patients with both blood and bile cultures positive, complete or partial concordance of organisms was noted in about 90%. CONCLUSION: Bile and blood cultures have a similar microbial profile in most patients with cholangitis. As bile cultures have a significantly higher yield than blood cultures, they could effectively guide antimicrobial therapy, especially in those with negative blood cultures.

Recurrent Acute Upper Gastrointestinal Bleed Due to Diffuse B-cell Lymphoma of the Duodenum in a Renal Transplant Patient: A Case Report and Literature Review.

A patient status post (s/p) renal transplantation in 2014 presented with an upper gastrointestinal bleed (UGIB). The source of the bleed was found to be a large mass in the duodenum with histopathology from biopsies obtained during esophagogastroduodenoscopy revealing diffuse large B-cell lymphoma (DLBCL) of the duodenum. His mycophenolate was stopped, and the tacrolimus dose was reduced due to active malignancy. He was discharged and completed one cycle of R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine, and prednisone) before presenting back to ED with hemorrhagic shock from a large upper GI bleed requiring admission to the medical intensive care unit. Post-transplant lymphoproliferative disorders such as DBLCL can present 10 years from the transplant date. These malignancies are at high risk for bleed, especially after treatment with chemotherapy is initiated.

Whipple's Disease Presenting With a Chief Complaint of Dyspnea and Cough From Pulmonary Invasion Without Evidence of Gastrointestinal Involvement.

A patient with immune thrombocytopenia, systemic lupus erythematosus on chronic corticosteroids, and interstitial lung disease was referred to the pulmonology clinic due to progressively worsening dyspnea. A bronchoscopy was done and a thorough workup was negative for any infectious pathology or malignancy. A lung biopsy with MicroGenDX test (MicroGen Diagnostics, Lubbock, TX) revealed Tropheryma whipplei, consistent with a Whipple disease diagnosis. Histopathology of biopsy specimens from an esophagogastroduodenoscopy showed moderate chronic active Helicobacter gastritis and unremarkable duodenal specimens without evidence of Tropheryma whipplei. For Helicobacter pylori gastritis, she was prescribed quadruple therapy with omeprazole, bismuth, metronidazole, and tetracycline. For pulmonary Whipple's disease, she completed two weeks of IV ceftriaxone, which led to improvement in dyspnea, and then was transitioned to 12 months of oral sulfamethoxazole-trimethoprim. In rare cases, Whipple's disease can present as isolated pulmonary disease without gastrointestinal involvement, especially in immunosuppressed patients with compromised lungs.

Clinical profile of 1208 newly diagnosed colorectal cancer patients in Tamil Nadu-A multi-centric survey.

BACKGROUND: An increasing incidence of colorectal cancer (CRC) is being reported in developing countries, including India. Most Indian studies on CRC are retrospective and single-centered. The present study is an attempt to understand the current clinical profile and stage of newly diagnosed CRCs across multiple centers in Tamil Nadu, India. METHODS: A multi-centric observational survey was conducted between September 1, 2021, and August 31, 2022, under the aegis of the Indian Society of Gastroenterology - Tamil Nadu chapter. Patients 18 years of age and older with a recent diagnosis of CRC fulfilling the inclusion criteria were prospectively recruited at the participating centers. Their demographic, clinical, biochemical, endoscopic, histopathologic, radiologic and risk factor details were systematically collected and analyzed. RESULTS: Across 23 centers in Tamil Nadu, 1208 patients were recruited. The male:female ratio was 1.49:1, while mean (SD) age was 57.7 (13.5) years. A majority (81.9%) were Tamils and 78.5% belonged to lower socioeconomic classes. The predominant symptoms were hematochezia (30.2%) and a change in bowel habits (27.5%). The most common locations were the rectum (34.3%) and rectosigmoid (15.1%). Synchronous CRCs were seen in 3.3% and synchronous colorectal polyps in 12.8%. Predisposing factors for CRC were seen in 2%. A past history of any cancer among CRC patients was obtained in 3.1% and a family history of any cancer was found in 7.6%. Patients who were either overweight or obese constituted 46.4% of the study population. At presentation, the predominant stages were stage III (44.7%) and stage IV (20.8%). CONCLUSIONS: A majority of patients with newly diagnosed CRC in Tamil Nadu belonged to the lower socioeconomic classes. About 60% had CRCs located within the reach of the flexible sigmoidoscope. Two-thirds of the patients exceeded stage II disease at presentation. TRIAL REGISTRATION: Not applicable.

Take a break: should breaks be enforced during digital breast tomosynthesis reading sessions?

OBJECTIVES: Digital breast tomosynthesis (DBT) can improve diagnostic accuracy compared to 2D mammography, but DBT reporting is time-consuming and potentially more fatiguing. Changes in diagnostic accuracy and subjective and objective fatigue were evaluated over a DBT reporting session, and the impact of taking a reporting break was assessed. MATERIALS AND METHODS: Forty-five National Health Service (NHS) mammography readers from 6 hospitals read a cancer-enriched set of 40 DBT cases whilst eye tracked in this prospective cohort study, from December 2020 to April 2022. Eye-blink metrics were assessed as objective fatigue measures. Twenty-one readers had a reporting break, 24 did not. Subjective fatigue questionnaires were completed before and after the session. Diagnostic accuracy and subjective and objective fatigue measures were compared between the cohorts using parametric and non-parametric significance testing. RESULTS: Readers had on average 10 years post-training breast screening experience and took just under 2 h (105.8 min) to report all cases. Readers without a break reported greater levels of subjective fatigue (44% vs. 33%, p = 0.04), which related to greater objective fatigue: an increased average blink duration (296 ms vs. 286 ms, p < 0.001) and a reduced eye-opening velocity (76 mm/s vs. 82 mm/s, p < 0.001). Objective fatigue increased as the trial progressed for the no break cohort only (ps < 0.001). No difference was identified in diagnostic accuracy between the groups (accuracy: 87% vs. 87%, p = 0.92). CONCLUSIONS: Implementing a break during a 2-h DBT reporting session resulted in lower levels of subjective and objective fatigue. Breaks did not impact diagnostic accuracy, which may be related to the extensive experience of the readers. CLINICAL RELEVANCE STATEMENT: DBT is being incorporated into many mammography screening programmes. Recognising that reporting breaks are required when reading large volumes of DBT studies ensures this can be factored in when setting up reading sessions. TRIAL REGISTRATION: Clinical trials registration number: NCT03733106 KEY POINTS: • Use of digital breast tomosynthesis (DBT) in breast screening programmes can cause significant reader fatigue. • The effectiveness of incorporating reading breaks into DBT reporting sessions, to reduce mammography reader fatigue, was investigated using eye tracking. • Integrating breaks into DBT reporting sessions reduced reader fatigue; however, diagnostic accuracy was unaffected.

Features in visible and Fourier transform infrared spectra confronting aspects of meat quality and fraud.

Rapid assessment of microbiological quality (i.e., Total Aerobic Counts, TAC) and authentication (i.e., fresh vs frozen/thawed) of meat was investigated using spectroscopic-based methods. Data were collected throughout storage experiments from different conditions. In total 526 spectra (Fourier transform infrared, FTIR) and 534 multispectral images (MSI) were acquired. Partial Least Squares (PLS) was applied to select/transform the variables. In the case of FTIR data 30 % of the initial features were used, while for MSI-based models all features were employed. Subsequently, Support Vector Machines (SVM) regression/classification models were developed and evaluated. The performance of the models was evaluated based on the external validation set. In both cases MSI-based models (Root Mean Square Error, RMSE: 0.48-1.08, Accuracy: 91-97 %) were slightly better compared to FTIR (RMSE: 0.83-1.31, Accuracy: 88-94 %). The most informative features of FTIR for the case of quality were mainly in 900-1700 cm-1, while for fraud the features were more dispersed.

Study of the transfer of Shiga toxin-producing Escherichia coli during the slaughter of cattle using molecular typing combined with epidemiologic data.

Investigation on the distribution and biological characteristics of Shiga-toxin producing Escherichia coli (STEC) during beef processing is essential for in-plant critical control points and food safety risk assessment. Serogroups and subtypes of stx genes of STEC strains isolated from beef processing lines were first investigated. Identification to cross-contamination among different sampling sites was further conducted by combining multilocus sequence typing (MLST) with the previous distribution and characterization data. The PCR-positive rate for STEC in 435 samples from two slaughter plants in China was 14.3% and the isolation rate for the 62 PCR positive and the entire set of 435 samples were 26% and 3.68% respectively. The existence of serotype O157:H7 (33%) and serogroups O121 (42%) and O26 (21%) as well as the high detection rate of high pathogenic gene stx2a (68%) in these serogroups indicated potential risk to the safety of beef. Traceability analysis showed that hide plays a critical role in cross-contamination between feces, lairage pens and post-washing carcasses from a molecular perspective. Intervening measures revolves around de-hiding should be involved in the in-plant safety control policy according to the tracing analysis.