Behavior of Salmonella during preparation of a fermented cashew cheese analog.

Between 2013 and 2021 there were three reported salmonellosis outbreaks in North America linked to consumption of cashew cheese analogs that were prepared from soaked and fermented cashews. The behavior of Salmonella was evaluated during fermentation of cashews to better understand the risks associated with plant-based fermentations. Single or seven-strain rifampin-resistant Salmonella-inoculated cashews (1 to 2 log CFU/g) were soaked 1:1 (w/v) in sterile ultrapure water at 4°C for 24 ± 1 h, drained, and then blended with additional water. Salmonella-inoculated or uninoculated cashews with or without added commercial Lactococcus lactis starter culture (LAB), and with LAB and NaCl (0.8% and 1.6% w/w), citric acid (0.4% w/w), or a combination of NaCl and citric acid, were held at 24 ± 1 °C for up to 72 h. The pH, aerobic plate counts (M17 agar), and Salmonella populations (CHROMagar Salmonella with 50 µg/mL of rifampin) were measured at 0, 24, 48, and 72 h in replicate experiments. When LAB was present, aerobic plate counts increased from ∼8 log CFU/g to ∼9 log CFU/g after 24 h. The pH decreased from an initial pH ∼6 to pH 4.5-5.0 at 24 h in the presence of LAB or at 48 h in the absence of LAB. The presence of LAB significantly (P < 0.0001) impacted populations of Salmonella during the fermentation. There was no significant difference in Salmonella populations between the treatments with LAB alone and the treatments with LAB in combination with added NaCl (P = 0.3484) or citric acid (P = 0.8630). After 24 h, populations of Salmonella increased by 5.3-5.5 log in the absence of LAB and by 0.5-1.7 log in the presence of LAB, with or without added NaCl. These data demonstrate the need to consider a range of control measures for safe preparation of plant-based fermented products.

Survival of Salmonella enterica and Enterococcus faecium on Abiotic Surfaces During Storage at Low Relative Humidity.

Currently, there is limited knowledge on the survival of bacteria on surfaces during postharvest handling of dry products such as onions. Extended survival of microorganisms, coupled with a lack of established and regular, validated cleaning or sanitation methods could enable cross-contamination of these products. The aim of the study was to evaluate the survival of a potential surrogate, Enterococcus faecium, and Salmonella enterica on typical onion handling surfaces, polyurethane (PU), and stainless steel (SS), under low relative humidity. The influence of onion extract on the survival of E. faecium and Salmonella on PU and SS was also investigated. Rifampin-resistant E. faecium NRRL B-2354 and a five-strain cocktail of Salmonella suspended in 0.1% peptone or onion extract were separately inoculated onto PU and SS coupons (2 × 2 cm), at high, moderate, or low (7, 5, or 3 log CFU/cm2) levels. The inoculated surfaces were stored at ∼34% relative humidity and 21°C for up to 84 days. Triplicate samples were enumerated at regular intervals in replicate trials. Samples were enriched when populations fell below the limit of detection by plating (0.48 log CFU/cm2). Scanning electron microscopy was used to observe the cell distribution on the coupons. Reductions of E. faecium of less than ∼2 log were observed on PU and SS over 12 weeks at all inoculum levels and with both inoculum carriers. In 0.1% peptone, Salmonella populations declined by 2 to 3 log over 12 weeks at the high and moderate inoculum levels; at the low inoculum level, Salmonella could not be recovered by enrichment at 84 days. Survival of E. faecium and Salmonella was significantly (P < 0.05) enhanced over 84 days of storage when suspended in onion extract, where cells were covered by a layer of onion extract. E. faecium might have utility as a conservative surrogate for Salmonella when evaluating microbial survival on dry food-contact surfaces.

A comparison between the role of enniatins and deoxynivalenol in Fusarium virulence on different tissues of common wheat.

BACKGROUND: Fusarium graminearum and Fusarium avenaceum are two of the most important causal agents of Fusarium head blight (FHB) of wheat. They can produce mycotoxins that accumulate in infected wheat heads, including deoxynivalenol (DON) and enniatins (ENNs), produced by F. graminearum and F. avenaceum, respectively. While the role of DON as a virulence factor in F. graminearum toward wheat is well known, ENNs in F. avenaceum has been poorly explored. Results obtained to-date indicate that ENNs may confer an advantage to F. avenaceum only on particular hosts. RESULTS: In this study, with the use of ENN-producing and ENN non-producing F. avenaceum strains, the role of ENNs on F. avenaceum virulence was investigated on the root, stem base and head of common wheat, and compared with the role of DON, using DON-producing and DON non-producing F. graminearum strains. The DON-producing F. graminearum strain showed a significantly higher ability to cause symptoms and colonise each of the tested tissues than the non-producing strain. On the other hand, the ability to produce ENNs increased initial symptoms of the disease and fungal biomass accumulation, measured by qPCR, only in wheat heads, and not in roots or stem bases. LC-MS/MS analysis was used to confirm the presence of ENNs and DON in the different strains, and results, both in vitro and in wheat heads, were consistent with the genetics of each strain. CONCLUSION: While the key role of DON on F. graminearum virulence towards three different wheat tissues was noticeable, ENNs seemed to have a role only in influencing F. avenaceum virulence on common wheat heads probably due to an initial delay in the appearance of symptoms.

Phenotypic Characteristics That May Contribute to Persistence of Salmonella Strains in the Pistachio Supply Chain.

Salmonella enterica subsp. enterica strain diversity in California pistachios is limited; some strains have persisted in the pistachio supply chain for ≥10 years. Representative isolates of six persistent strains and three sporadic strains isolated from California pistachios were selected to evaluate copper resistance, growth in pistachio hull slurry, biofilm formation, desiccation tolerance, and survival during subsequent storage. The presence of a copper homeostasis and silver-resistance island sequence in three of the persistent strains was associated with an increase in tolerance to CuSO4 from 7.5 mM to 15 mM under anaerobic but not aerobic conditions; all isolates were resistant to ≥120 mM Cu-EDTA under both anerobic and aerobic conditions. When inoculated into pistachio hull slurry at 2.75 ± 0.04 log CFU/mL and incubated at 30 °C, the populations of Salmonella Enteritidis strain A (sporadic) increased to significantly lower levels than the other strains at 16, 20, 24, and 28 h but not at 40 and 48 h. Maximum populations of 8.70-8.85 log CFU/mL were observed for all strains at ≥40 h of incubation. All nine Salmonella strains produced weak to strong biofilms after 4 days at 25 °C; seven strains, including two sporadic strains, produced moderate biofilms, and Salmonella Liverpool strain A (persistent) produced a strong biofilm. The rdar+ and rdar- morphotypes were observed in both persistent and sporadic Salmonella strains. Population declines of 5.03 log were observed for Salmonella Enteritidis strain A within 18 h of drying on filter paper whereas reductions of 0.50-1.25 log were observed for the other eight Salmonella strains. Population reductions (3.98-5.12 log) of these eight strains were not significantly different after storage at 25 ± 1 °C and 35% relative humidity for 50 days. The phenotypic characteristics evaluated here do not independently account for the persistence of a small number of Salmonella strains associated with the California pistachio production chain.

Reduction Foodborne Pathogens and Surrogate Microorganism on Citrus Fruits after Lab- and Pilot-scale Finishing Wax Application.

After finishing waxes are applied, citrus fruits are typically dried at 32-60°C for 2-3 min before final packing. The survival of Listeria monocytogenes, Salmonella, and Enterococcus faecium NRRL B-2354 was evaluated under laboratory conditions on lemons after applying one of four finishing waxes (F4, F6, F8, and F15) followed by an ambient hold or heated (50 or 60°C) drying step. The reduction of inoculated microorganisms during drying was significantly influenced by wax type and temperature, with greater reductions at higher temperatures. Greater reductions after waxing and drying at 60°C were observed with L. monocytogenes (2.84-4.44 log) than with Salmonella (1.65-3.67 log), and with Salmonella than with E. faecium (0.99-2.93 log). The survival of Salmonella inoculated at 5.8-5.9 log/fruit on lemons and oranges after applying wax F6 and drying at 60°C was evaluated during storage at 4 and 22°C. The reductions of Salmonella after waxing and drying were 1.7 log; additional reductions during storage at 4 or 22°C were 1.40-1.43 or 0.18-0.29 log, respectively, on waxed lemons, and 0.56-1.02 or 0.54-0.57 log, respectively, on waxed oranges. Under pilot-scale packinghouse conditions with wax F4, mean and minimum reductions of E. faecium ranged from 2.15 to 2.89 and 1.64 to 2.12 log, respectively. However, E. faecium was recovered by whole-fruit enrichment (limit of detection: 0.60 log CFU/lemon) but not by plating (LOD: 1.3 log CFU/lemon) from uninoculated lemons run with or after the inoculated lemons. The findings should provide useful information to establish and implement packinghouse food safety plans.

A Comparison of Remote vs In-Person Proctored In-Training Examination Administration for Internal Medicine.

PURPOSE: In response to COVID-19, the American College of Physicians provided residents the option to complete the 2020 Internal Medicine In-Training Examination (IM-ITE) via in-person and remote proctoring. This study evaluated the extent to which scores obtained from both testing modalities were comparable. METHOD: Data were analyzed from residents from all U.S.-based Accreditation Council for Graduate Medical Education-accredited IM residency programs and participating Canadian and international programs who completed the IM-ITE in 2020. The final sample contained 27,115 IM residents: 9,205 postgraduate year (PGY) 1, 9,332 PGY-2, and 8,578 PGY-3. Testing modality, gender, PGY, time spent on assessment, and native language were used to predict percent-correct scores in a multilevel regression model. This model included all main effects and all 2-way interactions between testing modality and each resident-level demographic variable, allowing those effects to be controlled for. RESULTS: Of 27,115 residents studied, 11,354 (42%) tested remotely and 15,761 (58%) in person. Across the parameters of interest (main effect of testing modality and 2-way interactions), the only statistically significant effects were the interaction effects between testing mode (interaction effect: -0.61; 95% confidence interval (CI): -1.01, -0.21) and PGY (interaction effect: -0.54; 95% CI: -0.95, -0.13) (P = .002). Differences between in-person and remote predicted scores were slightly larger for PGY-1 than for PGY-2 and PGY-3 residents (controlling for the other predictors in the model), but the magnitude of these differences across residency training was well under a single percentage point. Because these statistically significant effects were deemed educationally nonsignificant, the study concluded that performance did not substantively differ across in-person and remote examinees. CONCLUSIONS: Residents taking the 2020 IM-ITE performed similarly across in-person and remote proctoring. This study provides evidence of score comparability across the 2 testing modalities and supports continued use of remote proctoring for the IM-ITE.

Comparison of success and cost after retrieval of two inferior vena cava filters.

OBJECTIVE: The objective of this study was to help guide inferior vena cava (IVC) filter choices by better understanding the retrieval characteristics, complications, and total costs between two commonly used IVC filters. METHODS: All patients who underwent retrieval or attempted retrieval of Denali (Bard Peripheral Vascular) or Option (Argon Medical Devices) IVC filters were identified between March 2016 and October 2021 at a single tertiary care center. Those with imaging studies that permitted evaluation of filter placement, presence or degree of tilt, and/or hooking of the filter into the IVC wall were included in the present study. Filter retrieval success, number of attempts, use of advanced techniques, and fluoroscopy and procedural times were recorded and compared between the two filters. RESULTS: A total of 87 patients presented for retrieval of 52 Denali and 35 Option Elite filters during the study period. Denali filters were more likely to be successfully retrieved at the first attempt (94% vs 77%; P = .019). The procedural and fluoroscopy times were shorter for Denali filters (29 minutes vs 63 minutes [P < .001] and 7 minutes vs 25 minutes [P < .001], respectively). Denali filters were less likely to be significantly tilted (≥15○) at retrieval (12% vs 29%; P < .001) or to have the filter hook embedded in the IVC wall (6% vs 40%; P < .001). Tilting of the filter of ≥15○ had no significant effects on the retrieval success rate (no tilt or tilt <15○ vs tilt of ≥15○: 98% vs 100%; P = .58). In contrast, filter hook penetration into the IVC wall significantly reduced successful recovery (41% vs 99%; P < .001). CONCLUSIONS: The findings from this study suggest that although the filter designs are similar, a benefit exists in the ease of retrievability of the Denali over the Option filter. We found that tilting and hooking of the filter in the IVC wall occurred significantly more with the Option filter. These factors likely made retrieval more difficult and contributed to the longer procedure and fluoroscopy times.

Thoracic outlet syndrome in females: A systematic review.

Thoracic outlet syndrome (TOS) is a rare anatomic condition caused by compression of neurovascular structures as they traverse the thoracic outlet. Depending on the primary structure affected by this spatial narrowing, patients present with one of three types of TOS-venous TOS, arterial TOS, or neurogenic TOS. Compression of the subclavian vein, subclavian artery, or brachial plexus leads to a constellation of symptoms, including venous thrombosis, with associated discomfort and swelling; upper extremity ischemia; and chronic pain due to brachial plexopathy. Standard textbooks have reported a predominance of females patients in the TOS population, with females comprising 70%. However, there have been few comparative studies of sex differences in presentation, treatment, and outcomes for the various types of TOS.

Genetic diversity of Salmonella enterica isolated over 13 years from raw California almonds and from an almond orchard.

A comparative genomic analysis was conducted for 171 Salmonella isolates recovered from raw inshell almonds and raw almond kernels between 2001 and 2013 and for 30 Salmonella Enteritidis phage type (PT) 30 isolates recovered between 2001 and 2006 from a 2001 salmonellosis outbreak-associated almond orchard. Whole genome sequencing was used to measure the genetic distance among isolates by single nucleotide polymorphism (SNP) analyses and to predict the presence of plasmid DNA and of antimicrobial resistance (AMR) and virulence genes. Isolates were classified by serovars with Parsnp, a fast core-genome multi aligner, before being analyzed with the CFSAN SNP Pipeline (U.S. Food and Drug Administration Center for Food Safety and Applied Nutrition). Genetically similar (≤18 SNPs) Salmonella isolates were identified among several serovars isolated years apart. Almond isolates of Salmonella Montevideo (2001 to 2013) and Salmonella Newport (2003 to 2010) differed by ≤9 SNPs. Salmonella Enteritidis PT 30 isolated between 2001 and 2013 from survey, orchard, outbreak, and clinical samples differed by ≤18 SNPs. One to seven plasmids were found in 106 (62%) of the Salmonella isolates. Of the 27 plasmid families that were identified, IncFII and IncFIB plasmids were the most predominant. AMR genes were identified in 16 (9%) of the survey isolates and were plasmid encoded in 11 of 16 cases; 12 isolates (7%) had putative resistance to at least one antibiotic in three or more drug classes. A total of 303 virulence genes were detected among the assembled genomes; a plasmid that harbored a combination of pef, rck, and spv virulence genes was identified in 23% of the isolates. These data provide evidence of long-term survival (years) of Salmonella in agricultural environments.

Characterizing the Genetic Diversity of Salmonella Isolated from U.S. Raw Inshell Pistachios Using Whole Genome Sequencing.

The genetic diversity of 169 Salmonella isolates from pistachios collected from California storage silos during the 2010, 2011, and 2012 harvests (silo survey isolates) was determined by analyzing the whole genome sequence data using the CFSAN SNP pipeline developed by the U.S. Food and Drug Administration's Center for Food Safety and Applied Nutrition. Salmonella isolates clustered by serovars Agona, Enteritidis, Montevideo, Sandiego, Senftenberg, Liverpool, Tennessee, and Worthington in the phylogenetic tree. Within each serovar, isolates grouped into one or two clusters (≤14 SNPs). Two distinct clusters (>14 SNPs; A and B) were identified for Salmonella Enteritidis, Montevideo, and Liverpool for a total of 11 unique strains. Sequences of representative silo survey isolates clustered with sequences of Salmonella strains isolated from U.S. pistachio-associated samples collected between 2008 and 2018 available on the National Center for Biotechnology Information database, and, in all but two cases, not with sequences of Salmonella strains recovered from raw California almonds from 2001 through 2013. The genomic evidence suggests that strains of Salmonella Agona, Liverpool Cluster A, Montevideo Clusters A and B, Senftenberg, and Worthington have persisted in the California pistachio environment for ≥3 years and some of these strains have been reported exclusively in association with pistachios.

Survival of Listeria monocytogenes and Salmonella in citrus storage waxes or on lemons held under common commercial storage conditions.

To prolong cold storage, diluted storage waxes are applied to washed lemons after harvest and before packing, without drying steps, to reduce premature rotting and water loss. The survival of Listeria monocytogenes and Salmonella in undiluted and diluted storage waxes (S1-S4), and on lemon surfaces under common commercial storage were investigated. Populations of L. monocytogenes declined more slowly than Salmonella in undiluted storage waxes over 24 h of storage at 4 or 22 °C. L. monocytogenes (inoculated at ∼6 log CFU/mL) was detected by enrichment in undiluted waxes S2, S3, and S4 after 75-135 days at 4 °C but not after 30, 10, or 105 days, respectively at 22 °C. L. monocytogenes survived better in diluted than in undiluted storage waxes at 22 °C. Populations of L. monocytogenes (∼6 log CFU/lemon) declined by 0.64-1.62 log on lemon surfaces right after waxing. Populations of L. monocytogenes decreased to <1.30 log CFU/lemon after 28 days (1:9 S1) or 75 days (other treatments) at 12 °C and ≥93% RH. Except for 1:9 S1, L. monocytogenes was detected by enrichment in all lemon samples over 87 days of storage. Packinghouses should consider the survival of L. monocytogenes and Salmonella in citrus storage waxes in their food safety programs.

Transfer of Enterococcus faecium and Salmonella enterica during simulated postharvest handling of yellow onions (Allium cepa).

Bacterial transfer during postharvest handling of fresh produce provides a mechanism for spreading pathogens, but risk factors in dry environments are poorly understood. The aim of the study was to investigate factors influencing bacterial transfer between yellow onions (Allium cepa) and polyurethane (PU) or stainless steel (SS) under dry conditions. Rifampin-resistant Enterococcus faecium NRRL B-2354 or a five-strain cocktail of Salmonella was inoculated onto onion skin or PU surfaces at high or moderate levels using peptone, onion extract, or soil water as inoculum carriers. Transfer from inoculated to uninoculated surfaces was conducted using a texture analyzer to control force, time, and number of contacts. Transfer rates (ratio of recipient surface to donor surface populations) of E. faecium (4-5%) were significantly higher than those of Salmonella (0.5-0.6%) at the high (7 log CFU/cm2) but not moderate (5 log CFU/cm2) inoculum levels. Significantly higher populations of E. faecium transferred from onion to PU than from PU to onion. The transfer rates of E. faecium were impacted by inoculum carrier (61% [onion extract], 1.6% [peptone], and 0.31% [soil]) but not by inoculation level or recipient surface (PU versus SS). Bacterial transfer during dry onion handling is significantly dependent on bacterial species, inoculation levels, inoculum carrier, and transfer direction.

Association Between Conduit Type and Outcomes After Open Repair of Popliteal Artery Aneurysms.

INTRODUCTION: Prior studies have demonstrated acceptable midterm outcomes with prosthetic conduits for above-knee bypass for occlusive disease in patients with inadequate segment great saphenous vein (GSV). In this study we aimed to investigate whether this holds true for open repair of popliteal artery aneurysms (PAA). METHODS: We queried the Vascular Quality Initiative data for patients who underwent open PAA repair (OPAR). We divided the cohort into three groups based on the conduit used: GSV, other autologous veins, or prosthetic graft. Study outcomes included primary patency, freedom from major amputation, amputation-free survival, and overall survival at 1 y. Kaplan-Meier survival estimates, log-rank tests and multivariable Cox regression were used to compare outcomes between study groups. RESULTS: A total of 4016 patients underwent bypass for PAA from January 2010 to October 2021. The three cohorts were significantly different in many demographic and clinical characteristics. The adjusted odds of postoperative amputation among symptomatic patients were 3-fold higher for prosthetic conduits compared to the GSV (odds ratio, 3.20; 95% CI, 1.72-5.92; P < 0.001). For the 1-y outcomes, the adjusted risk of major amputation was almost 3-fold higher for patients with symptomatic disease undergoing bypass with prosthetic conduits (hazard ratio [HR], 2.97; 95% CI, 1.35-6.52; P = 0.007). When compared with GSV, prosthetic conduits were associated with 96% increased risk of death when used for repair in symptomatic patients (adjusted hazard ratio (aHR), 1.96; 95% CI, 1.29-2.97; P = 0.002) but no significant association with mortality in asymptomatic patients (aHR, 0.83; 95% CI, 0.37-1.87; P = 0.652). When compared with GSV, prosthetic conduits were associated with a 2-fold increased risk of 1-y major amputation or death when used for repair in symptomatic patients (aHR, 2.03; 95% CI, 1.40-2.94; P < 0.001) but no significant association with mortality in asymptomatic patients (aHR, 0.91; 95% CI, 0.42-1.98; P = 0.816). Comparing bypass with other veins to the GSV among patients with symptomatic disease, there was no statistically significant difference in major amputation risk (HR; 2.44; 95% CI, 0.55-10.82; P = 0.242) and no difference in the adjusted risk of all-cause mortality (aHR, 0.77; 95% CI, 0.26-2.44; P = 0.653). There were no differences in the adjusted risk of loss of primary patency comparing other veins to GSV (HR, 1.53; 95% CI, 0.85-2.76; P = 0.154) and prosthetic conduits to GSV (HR, 0.85; 95% CI, 0.57-1.26; P = 0.422). CONCLUSIONS: This large study shows that among patients undergoing OPAR, 1-y primary patency does not differ between conduit types. However, prosthetic conduits are associated with significantly higher risk of amputation and death compared to GSV among symptomatic patients. Though non-GSV autologous veins are less often used for OPAR, they have comparably acceptable outcomes as GSV.

U.S. Consumer Practices of Homemade Nut-based Dairy Analogs and Soaked Nuts.

Tree nuts, a low-moisture food, are typically perceived as being a low risk for foodborne illness. In the past five decades, the consumption of tree nuts (dry, soaked, or as nut-based dairy analogs [NBDA]) has increased along with corresponding foodborne illness outbreaks and recalls associated with these products. We developed an online survey to assess tree nut handling practices of U.S. consumers, and to select study participants who have soaked tree nuts and/or made NBDA at home. We distributed our initial survey questions in October 2021 to a convenience sample (n = 12) to test for clarity and comprehension. In January 2022, participants (n = 981) who met the criteria completed the survey. The most popular soaked tree nuts were almonds (54%), followed by cashews (36%), walnuts (32%), and pistachios (22%). Participants soaked tree nuts for direct consumption (67%) and during the preparation of NBDA (80%). Participants soaked tree nuts under refrigerated conditions for 1-24 h (22%), on the countertop at room temperature (est. 65-75°F [18-24°C]) for 1-5 h (21%), or at room temperature for 12 h or more (6%); 16% used a hot or boiling water, short time treatment. Some participants added acid (28%) or salt (25%) to the soaking water. Among those participants who dried their tree nuts after soaking (63%), 89% reported drying at a temperature lower than 46°C (115°F). Some participants (34%) used their tree nuts to make fermented dairy analogs (e.g., "cheese" or "yogurt") by adding "probiotics" (56-86%) or a yogurt starter culture (37-99%), respectively, and then, most frequently, holding at or below 20°C (68°F) for 12 h or less (29%). The safety of many of these practices has not been adequately investigated, but the findings of this study will inform future risk assessment and risk modeling studies on tree nut food safety in home kitchen settings.

Dual-Scan Photoacoustic Tomography for the Imaging of Vascular Structure on Foot.

Chronic leg ulcers are affecting approximately 6.5 million Americans, and they are associated with significant mortality, reduced quality of life, and high treatment costs. Since many chronic ulcers have underlying vascular insufficiency, accurate assessment of tissue perfusion is critical to treatment planning and monitoring. This study introduces a dual-scan photoacoustic (PA) tomography (PAT) system that can simultaneously image the dorsal and plantar sides of the foot to reduce imaging time. To account for the unique shape of the foot, the system employs height-adjustable and articulating baseball stages that can scan along the foot's contour. In vivo results from healthy volunteers demonstrate the system's ability to acquire clear images of foot vasculature, and results from patients indicate that the system can image patients with various ulcer conditions. We also investigated various PA features and examined their correlation with the foot condition. Our preliminary results indicate that vessel sharpness, occupancy, intensity, and density could all be used to assess tissue perfusion. This research demonstrated the potential of PAT for routine clinical tissue perfusion assessment.