Post-harvest Samples Research Articles

Temporal Accumulation of Geosmin, Oxalic Acid, and Total Dissolved Solids in Table Beet

Consumers perceive flavor as a critically important attribute of vegetable crops. Gas chromatography-mass spectrometry (GC-MS), spectrophotometry, and refractometry of tissue samples collected during multiple years from table beet (Beta vulgaris) at various stages of maturity were performed to characterize the endogenous production of geosmin, oxalic acid, and total dissolved solids within the root. The geosmin concentration was primarily influenced by the cultivar and peaked early during the growing season, with root concentrations at 6 weeks after planting that were 312% higher, on average, than those found in harvest stage roots at 15 weeks after planting. The highest average concentration of geosmin in harvest stage roots was detected in tissue from the cultivar Bull’s Blood (16.08 μg⋅kg−1). The oxalic acid concentration showed a strong cultivar influence and statistically significant variability across the growing season. Hybrid beet cultivar Boro had the lowest soluble oxalic acid concentration (95.73 mg⋅100 g−1 fresh tissue) at all locations and during all years. The oxalic acid concentration peaked 12 weeks after planting, and it was lower at the postharvest sampling date 18 weeks after planting. Total dissolved solids (TDS) concentrations were strongly influenced by year and growing environment and displayed crossover interactions for environment × week. TDS measurements had a moderate negative correlation with root mass. ‘Chioggia Guardsmark’ consistently had the highest TDS during all years and at all locations at 12.01 °Brix. The TDS varied significantly according to time, and diurnal sampling revealed fluctuations as large as 4 °Brix over the course of a 12-hour period. The TDS concentrations increased throughout the growing season, although the rate at which they increased changed according to plant age. The results from this study suggest that interactions between cultivar, time, and environment are important determinants of oxalic acid and TDS concentrations, but they have less influence on geosmin. This information may influence the methods that plant breeders use to collect phenotypic data of important flavor compounds in beets.

Assessment of the prevalence, serotype, and antibiotic resistance pattern of Salmonella enterica in integrated farming systems in the Maryland-DC area.

Implementation of organic/pasture farming practices has been increasing in the USA regardless of official certification. These practices have created an increasingly growing demand for marketing safe products which are produced through these systems. Products from these farming systems have been reported to be at greater risk of transmitting foodborne pathogens because of current trends in their practices. Salmonella enterica (SE) is a ubiquitous foodborne pathogen that remains a public health issue given its prevalence in various food products, but also in the environment and as part of the microbial flora of many domestic animals. Monitoring antibiotic resistance and identifying potential sources contamination are increasingly important given the growing trend of organic/pasture markets. This study aimed to quantify prevalence of SE at the pre- and post-harvest levels of various integrated farms and sites in Maryland-Washington D.C. area, as well as identify the most prevalent serovars and antibiotic resistance patterns. Samples from various elements within the farm environment were collected and screened for SE through culture and molecular techniques, which served to identify and serotype SE, using species and serovar-specific primers, while antibiotic resistance was evaluated using an antibiogram assay. Results showed a prevalence of 7.80% of SE pre-harvest and 1.91% post-harvest. These results also showed the main sources of contamination to be soil (2.17%), grass (1.28%), feces (1.42%) and unprocessed produce (1.48%). The most commonly identified serovar was Typhimurium (11.32%) at the pre-harvest level, while the only identified serovar from post-harvest samples was Montevideo (4.35%). With respect to antibiotic resistance, out of the 13 clinically relevant antibiotics tested, gentamycin and kanamycin were the most effective, demonstrating 78.93 and 76.40% of isolates, respectively, to be susceptible. However, ampicillin, amoxicillin and cephradine had the lowest number of susceptible isolates with them being 10.95, 12.36, and 9.83%, respectively. These results help inform farms striving to implement organic practices on how to produce safer products by recognizing areas that pose greater risks as potential sources of contamination, in addition to identifying serotypes of interest, while also showcasing the current state of antibiotic efficacy and how this can influence antibiotic resistance trends in the future.

Combined Quantification and Deep Serotyping for Salmonella Risk Profiling in Broiler Flocks.

Despite a reduction of Salmonella contamination on final poultry products, the level of human salmonellosis cases attributed to poultry has remained unchanged over the last few years. There needs to be improved effort to target serovars which may survive antimicrobial interventions and cause illness, as well as to focus on lessening the amount of contamination entering the processing plant. Advances in molecular enumeration approaches allow for the rapid detection and quantification of Salmonella in pre- and postharvest samples, which can be combined with deep serotyping to properly assess the risk affiliated with a poultry flock. In this study, we collected a total of 160 boot sock samples from 20 broiler farms across four different integrators with different antibiotic management programs. Overall, Salmonella was found in 85% (68/80) of the houses, with each farm having at least one Salmonella-positive house. The average Salmonella quantity across all four complexes was 3.6 log10 CFU/sample. Eleven different serovars were identified through deep serotyping, including all three key performance indicators (KPIs; serovars Enteritidis, Infantis, and Typhimurium) defined by the U.S. Department of Agriculture-Food Safety and Inspection Service (USDA-FSIS). There were eight multidrug resistant isolates identified in this study, and seven which were serovar Infantis. We generated risk scores for each flock based on the presence or absence of KPIs, the relative abundance of each serovar as calculated with CRISPR-SeroSeq (serotyping by sequencing the clustered regularly interspaced palindromic repeats), and the quantity of Salmonella organisms detected. The work presented here provides a framework to develop directed processing approaches and highlights the limitations of conventional Salmonella sampling and culturing methods. IMPORTANCE Nearly one in five foodborne Salmonella illnesses are derived from chicken, making it the largest single food category to cause salmonellosis and indicating a need for effective pathogen mitigation. Although industry has successfully reduced Salmonella incidence in poultry products, there has not been a concurrent reduction in human salmonellosis linked to chicken consumption. New efforts are focused on improved control at preharvest, which requires improved Salmonella surveillance. Here, we present a high-resolution surveillance approach that combines quantity and identity of Salmonella in broiler flocks prior to processing which will further support improved Salmonella controls in poultry. We developed a framework for this approach, indicating that it is possible and important to harness deep serotyping and molecular enumeration to inform on-farm management practices and to minimize risk of cross-contamination between flocks at processing. Additionally, this framework could be adapted to Salmonella surveillance in other food animal production systems.

Effect of Three Post-Harvest Methods at Different Altitudes on the Organoleptic Quality of C. canephora Coffee

C. canephora (syn. C. robusta) is distinctive due to its rising industrial value and pathogen resistance. Both altitude and post-harvest methods influence coffee cup quality; however, modest information is known about this coffee species. Therefore, the aim of this study was to determine the relationship between four different altitudes and post-harvest processes (dry, honey, and wet) to the improvement of the organoleptic quality of the C. canephora congolensis and conilon drink. For dry processing, congolensis and conilon showed the lowest scores in terms of fragrance/aroma, flavour, aftertaste, salt–acid, bitter–sweet, and body. Above 625 m, coffees from dry, honey, and wet processes increased scores in their sensory attributes, but there was no difference at such high altitudes when comparing post-harvest samples. Dry-processed coffee samples had total scores over 80 points at high altitudes. Conilon was perceived to have the best sensory attributes at high altitudes using honey processing. In general, the wet-processed congolensis and conilon samples had a tastier profile than dry-processed ones.

Fungal Species and Multi-Mycotoxin Associated with Post-Harvest Sorghum (Sorghum bicolor (L.) Moench) Grain in Eastern Ethiopia.

Sorghum is the main staple food crop in developing countries, including Ethiopia. However, sorghum grain quantity and quality are affected by contaminating fungi both under field and post-harvest stage. The aim of the current study was to assessed fungal species and multi-mycotoxins associated with sorghum grain in post-harvest samples collected from eastern Ethiopia. Fungal genera of Aspergillus, Alternaria, Bipolaris, Fusarium, Mucor, Penicillium, and Rhizoctonia were recovered in the infected grain. A liquid chromatography-tandem mass spectrometric (LC-MS/MS) was used for quantification of multiple mycotoxins/fungal metabolites. Overall, 94 metabolites were detected and grouped into eight categories. All metabolites were detected either in one or more samples. Among major mycotoxins and derivatives, deoxynivalenol (137 μg/kg), zearalenone (121 μg/kg), ochratoxin A (115 μg/kg), and fumonisin B1 (112 μg/kg) were detected with maximum concentrations, while aflatoxin B1 had relatively lower concentrations (23.6 μg/kg). Different emerging mycotoxins were also detected, with tenuazonic acid (1515 μg/kg) occurring at the maximum concentration among Alternaria metabolites. Fusaric acid (2786 μg/kg) from Fusarium metabolites and kojic acid (4584 μg/kg) were detected with the maximum concentration among Fusarium and Aspergillus metabolites, respectively. Unspecific metabolites were recognized with neoechinulin A (1996 μg/kg) at the maximum concentration, followed by cyclo (L-Pro-L-Tyr) (574 μg/kg) and cyclo (L-Pro-L-Val) (410 μg/kg). Moreover, metabolites form other fungal genera and bacterial metabolites were also detected at varying levels. Apparently, the study revealed that sorghum grains collected across those districts were significantly contaminated with co-occurrences of several mycotoxins. Farmers should be the main target groups to be trained on the improved management of sorghum production.

Characteristics and Global Occurrence of Human Pathogens Harboring Antimicrobial Resistance in Food Crops: A Scoping Review

BackgroundThe role of the crop environment as a conduit for antimicrobial resistance (AMR) through soil, water, and plants has received less attention than other sectors. Food crops may provide a link between the agro-environmental reservoir of AMR and acquisition by humans, adding to existing food safety hazards associated with microbial contamination of food crops.ObjectivesThe objectives of this review were: (1) to use a systematic methodology to characterize AMR in food crop value chains globally, and (2) to identify knowledge gaps in understanding exposure risks to humans.MethodsFour bibliographic databases were searched using synonyms of AMR in food crop value chains. Following two-stage screening, phenotypic results were extracted and categorized into primary and secondary combinations of acquired resistance in microbes of concern based on established prioritization. Occurrence of these pathogen-AMR phenotype combinations were summarized by sample group, value chain stage, and world region. Sub-analyses on antimicrobial resistance genes (ARG) focused on extended-spectrum beta-lactamase and tetracycline resistance genes.ResultsScreening of 4,455 citations yielded 196 studies originating from 49 countries, predominantly in Asia (89 studies) and Africa (38). Observations of pathogen-phenotype combinations of interest were reported in a subset of 133 studies (68%). Primary combinations, which include resistance to antimicrobials of critical importance to human medicine varied from 3% (carbapenem resistance) to 13% (fluoroquinolones), whereas secondary combinations, which include resistance to antimicrobials also used in agriculture ranged from 14% (aminoglycoside resistance) to 20% (aminopenicillins). Salad crops, vegetables, and culinary herbs were the most sampled crops with almost twice as many studies testing post-harvest samples. Sub-analysis of ARG found similar patterns corresponding to phenotypic results.DiscussionThese results suggest that acquired AMR in opportunistic and obligate human pathogens is disseminated throughout food crop value chains in multiple world regions. However, few longitudinal studies exist and substantial heterogeneity in sampling methods currently limit quantification of exposure risks to consumers. This review highlights the need to include agriculturally-derived AMR in monitoring food safety risks from plant-based foods, and the challenges facing its surveillance.

Macroinvertebrate responses to differing riparian treatments following forest harvest in the headwaters of Trask River watershed

Although it is well-established that macroinvertebrates are an integral part of a healthy stream ecosystem, studies designed to inform forest harvest best management practices for sustainability of macroinvertebrate communities in small streams have been limited. Current riparian management practices for headwater streams generally focus on providing adequate wood supply, reducing debris flows and transport of sediment, and maintaining water quality in larger streams that contain fish. Here we studied the effects of contemporary forest harvest practices on benthic macroinvertebrate density and community composition in 12 small headwater streams as part of the Trask River Watershed Study. To account for seasonal and year-to-year variability in macroinvertebrate densities, we sampled each site at the same time of year for six years before and four years after harvest. Three watersheds were clearcut with variable riparian buffers, three were clearcut with 12 m riparian buffers, and one was thinned with 15 m buffers. Five adjacent watersheds were not treated and were studied as reference sites. All sites had approximately 50 yr old conifer and alder forests, which had revegetated following fires and harvest in prior decades.In these steep mountain streams, benthic macroinvertebrate density and community composition were generally similar across watersheds prior to harvest. Collectors were the most abundant functional feeding group, followed by shredders; scrapers were the least abundant. After harvest, in two of the three clearcut watersheds with variable buffers, the total benthic density and percentage of collectors increased, primarily due to greater numbers of Chironomidae. We also observed more abundant emergence post-harvest at these two watersheds. In the third clearcut watershed with a variable buffer and in the three clearcut watersheds with uniform 12 m riparian buffers, we did not see changes in density or functional feeding groups after harvest. We explored the spatial and temporal aspects of the data using both non-parametric and parametric statistical methods. High variability swamped the treatment effect when watersheds were grouped by riparian treatment for the repeated measure analyses, while NMDS showed a significant shift post-harvest for the watersheds with variable buffers. In the clearcut watersheds with uniform buffers, macroinvertebrates densities and community composition did not shift. At two of the clearcut watersheds with variable buffers, we observed increased density for the first two years after harvest, and chironomids comprised up to 80% of the abundance in samples. In the subsequent years, we documented mixed responses for two watersheds. It was invaluable to have multiple pre- and post-harvest sampling periods in both harvested and reference watersheds in order to better identify site specific responses to treatment and to separate background variability from responses to harvest. We show that retention of riparian vegetation on headwater streams during clearcut harvesting minimized changes in total macroinvertebrate densities and community composition. Small buffers may be key to maintenance of diverse stream invertebrate communities in headwaters.

Postharvest-induced microbiota remodeling increases fungal diversity in the phyllosphere mycobiota of broccoli florets

Fresh vegetables harbor numerous microbial populations in their phyllosphere. The phyllosphere microbiota is important not only for enhancing crop production, but also maintaining the quality and safety of fresh vegetables. However, studies of fungal communities on fresh vegetables are lacking, and very little is known about changes to fungal communities after harvest. This study explored the phyllosphere mycobiota of broccoli florets collected from 14 farms (n = 42, preharvest) and 10 retail stores (n = 40, postharvest) by culturing and amplicon sequencing of an internal transcribed spacer region. Core genera were identified that were specific to the broccoli phyllosphere. Fungal populations exceeded bacterial populations in both total abundance and biodiversity, and fungal communities differed much more between preharvest and postharvest samples than bacterial communities. The fungal variance explained by postharvest (25.4 %) was larger than the variance by farming region (10.9 %) or practice (10.9 %), but the bacterial variance by postharvest (3.5 %) was lower than that by farming region (19.5 %) or practice (9.5 %). Both species richness and evenness were significantly higher in postharvest samples, and the Ascomycota-to-Basidiomycota ratio was significantly lower in postharvest samples than in preharvest samples. Microbial association network analysis illustrated that preharvest interspecies interactions involving Purpureocillium and Cystofilobasidium were replaced with interactions involving Sporobolomyces, Papiliotrema, and Bulleromyces in postharvest samples, resulting in a decrease of network robustness, as corroborated by functional changes and enrichment of a postharvest pathogen. Overall, the fungal community is an important component of postharvest microbiome in the phyllosphere of fresh vegetables that has large potential impacts on fresh produce storage and spoilage.

Difference in corn kernel moisture content between pre- and post-harvest

The harvest method of shelling corn (Zea mays L.) kernels in the field decreases labor costs associated with transporting, drying and threshing the crop. However, it was previously found that the kernel moisture content increased after field harvest, which decreased the value of corn kernels. To identify the reasons underlying the increase, we conducted a multiyear and -area trial in the Huang-Huai-Hai Plain, China and performed a staged-harvest test at several phases of kernel dry-down. The test investigated a range of parameters such as the kernel moisture content pre- and post-harvest, the kernel breakage rate, the amount of impurities, and the moisture content of various other plant tissues. An analysis of 411 pairs of pre- and post-harvest samples found that kernel moisture content after harvest was 2.2% higher than that before harvest. In the staged-harvest test, however, a significant increase was only observed when the kernel moisture content before harvest was higher than 23.9%. The increase in post-harvest kernel moisture content was positively associated with the pre-harvest kernel moisture content, breakage rate and impurity rate. Typically, at harvest time in this region, there is a significant fraction of immature crops with a high moisture content, resulting in kernels that are prone to breakage or impurities that ultimately lead to increases in water content after harvest. Therefore, we suggest using hybrids that quickly wither late in the growing stage. Additionally, farmers should delay harvest in order to minimize the pre-harvest kernel moisture content and thus reduce breakages and impurities, thereby improving the quality of kernels after harvest and the efficiency of corn kernel farming in China.

Farm management practices that affect the prevalence of Salmonella in pastured poultry farms

Farm practices can affect the prevalence of Salmonella in the final product when poultry are exposed to the outside environment. Pastured poultry farms in the Southeastern United States were investigated in this study. Farm practice and processing variables that may affect the presence of Salmonella were determined by developing predictive models using the random forest method. Important variables affecting the prevalence of Salmonella in preharvest (feces and soil), and postharvest (whole carcass rinses) samples were identified. Predictive models were generated with each type of sample, and the models were tested with the corresponding test set. The model performances were measured by the area under curve (AUC) values from the receiver operating characteristic (ROC) curve. All models developed in this study were robust in predicting Salmonella presence, with AUC values above 0.83. It was found that as the number of years of operation increased, there was increase in predicted probability of finding Salmonella. The first three ingredients in the brood and pasture feed were identified as the top predicting variables for both preharvest and postharvest variables. These models and data can help to inform pastured poultry producers about management practices that can reduce Salmonella prevalence within their production systems.

Direct and residual effect of organic manure amended sulphur on yield and nutrient uptake in mustard-rice cropping system

An experiment was conducted to evaluate the direct effect of different level of sulphur alone or in combination with organic manures on mustard and residual effect on rice crops in calcareous soil of north India. Sulphur application significantly increased the yield of mustard as well as rice, S concentration and its uptake by mustard (seed+stover) as well as available –S content in post- harvest soil samples after mustard and rice (grain+straw). The optimum level of S was worked out to be 60 kg S ha -1 for mustard seed and stover production. However, with regards to total S uptake, the optimum dose appeared at 100 kg S ha-1. The beneficial effect of organic manure was evident in enhancing the seed and stover production, S-c oncentration in seed, S-uptake (Seed+Stover) by mustard and available-S content in post-harvest soil samples from 9.8 to 10.7 q ha-1, 37.5 to 40.5 q ha-1, 0.779 to 0.821 per cent, 20.39 to 32.47 kg ha-1 and 25.7 to 86.5 mg kg-1, respectively and the grain yield, S-content in grain, straw, total S-uptake (grain + straw) and available S content in post-harvest samples of rice from 47.2 to 49.8 q ha-1, 0.088 to 0.098 per cent, 0.123 to 0.175 per cent, 13.83 to 17.98 kg ha-1 and 24.2 to 37.9 mg kg-1, respectively. Among the organic manures, biogas slurry (BGS) proved to be better source in enhancing seed yield, stover/straw yield, S-uptake, and available-S in post-harvest soil samples after mustard and rice. The residual effect of higher level of S along with BGS proved more effective with respect to S nutrition to rice.

Preharvest application of sodium nitroprusside improves tomato fruit quality and alleviates chilling injury during cold storage

ABSTRACT Nitric oxide (NO), a PGR, is involved in numerous physiological and molecular responses in higher plants. The study was undertaken to determine how preharvest application of NO affected physical and biochemical postharvest properties and chilling injury of tomato fruit, cv. Newton, during cold storage. Tomato plants were treated twice with 200 or 500 µM sodium nitroprusside (SNP), or distilled water, at 41 and 49 days post anthesis. For postharvest analyses samples were taken at 0, 5, 10, 15, and 20 days of storage at 1 ± 0.2°C and 90% ± 5% RH and transferred to ambient temperature (~24°C) for 2 days. The SNP delayed weight loss, increased total soluble solids, and maintained firmness of fruit during storage. Vitamin C, titratable acidity, lycopene content, superoxide dismutase, and peroxidase enzyme activity were higher due to SNP treatment than for the control. The SNP treatment decreased percent chilling injury. The 200 μm SNP concentration was best for preserving postharvest quality of tomato fruit. Preharvest application of SNP improved postharvest quality and mitigated deleterious effects of chilling injury of tomato fruit during cold storage.

Productivity, chemical composition and sensory quality of “Martaínha” chestnut variety treated with Silicon

ABSTRACTThe increasing demand for healthy products rises the pressure on the chestnut production due to their nutritional qualities and beneficial health effects. Martaínha chestnut variety is most well-adapted with great economic importance due to its precocity and technological properties. The exogenous application of Silicon has an important role in agriculture because of improvement of plants nutrition. Nevertheless, the knowledge of impact of Silicon application in the production, sensory quality and chemical composition of chestnut fruits is limited. The application of Si in leaves (SL) and soil (SS) have important action on the prophylactic properties and the promotion of chestnuts health. Moreover, higher number of healthy fruits, caliber, fruits without rotten and tortrix infection and lower water loss in post-harvest chestnuts, in SL and SS samples, highlights the Si positive action. Additionally this study emphasizes some positive effects of Silicon on the chemical and sensory profile.

Salmonella, Escherichia coli and Enterobacteriaceae in the peanut supply chain: From farm to table

Due to recent foodborne outbreaks, peanuts have been considered a potential risk for Salmonella transmission. For this reason, the aim of this study was to determine the prevalence and contamination load of Salmonella, Escherichia coli and Enterobacteriaceae throughout the peanut supply chain in Brazil. Samples of peanuts and peanut-containing processed products from post-harvest (n=129), secondary processing (n=185) and retail market (n=100) were analyzed. The results showed high Enterobacteriaceae counts in the post-harvest samples. At the end of the secondary processing, 16% of the samples remained contaminated by this group of microorganisms. Six peanut samples from primary production and one sample of peanut butter were tested positive for E. coli while Salmonella was detected in nine samples (2.2%): six from post-harvest, two from the initial stage of the secondary processing and one from retail. The Salmonella counts ranged between 0.004 and 0.092MPN/g and five serotypes were identified (Muenster, Miami, Javiana, Oranienburg, Glostrup). The results demonstrated a high prevalence of Enterobacteriaceae and low prevalence of E. coli throughout the peanut supply chain. Furthermore, it was verified that peanuts may become contaminated by Salmonella during different stages of the supply chain, especially at post-harvest.

Study of Post-Harvest Ambon Banana (Musa acuminata) Preservation Using X-Ray

An exposure to Ambon banana (Musa Acuminata) samples has been done by using X-rays with current, voltage and exposure time are control parameters. This study aimed to determine storage ability of the post-harvest sample. Five samples were exposured by x-rays with the dose of (3-5) × 10-14 Gy. The samples were stored at room temperature. Their mass and physical condition (color and smell) were evaluated every 3 days. It was found that the control sample which was not exposured by X-ray was ripe in the sixth day indicated by the yellow color and good smell of the banana. Meanwhile, the samples which were exposured by (3 - 5) × 10-14 Gy doze of X-ray looked fresher and still had green color. These samples showed their ripening in the ninth day and their mass decrease was (12-13)% which is lower than the control sample. The preservation of banana can be done through low-dose X-ray exposure.

Validation of Reference Genes for RT-qPCR Studies of Gene Expression in Preharvest and Postharvest Longan Fruits under Different Experimental Conditions

Reverse transcription quantitative PCR (RT-qPCR) as the accurate and sensitive method is use for gene expression analysis, but the veracity and reliability result depends on whether select appropriate reference gene or not. To date, several reliable reference gene validations have been reported in fruits trees, but none have been done on preharvest and postharvest longan fruits. In this study, 12 candidate reference genes, namely, CYP, RPL, GAPDH, TUA, TUB, Fe-SOD, Mn-SOD, Cu/Zn-SOD, 18SrRNA, Actin, Histone H3, and EF-1a, were selected. Expression stability of these genes in 150 longan samples was evaluated and analyzed using geNorm and NormFinder algorithms. Preharvest samples consisted of seven experimental sets, including different developmental stages, organs, hormone stimuli (NAA, 2,4-D, and ethephon) and abiotic stresses (bagging and girdling with defoliation). Postharvest samples consisted of different temperature treatments (4 and 22°C) and varieties. Our findings indicate that appropriate reference gene(s) should be picked for each experimental condition. Our data further showed that the commonly used reference gene Actin does not exhibit stable expression across experimental conditions in longan. Expression levels of the DlACO gene, which is a key gene involved in regulating fruit abscission under girdling with defoliation treatment, was evaluated to validate our findings. In conclusion, our data provide a useful framework for choice of suitable reference genes across different experimental conditions for RT-qPCR analysis of preharvest and postharvest longan fruits.

Prevalence and antibiotic resistance pattern of Salmonella serovars in integrated crop‐livestock farms and their products sold in local markets

Major concern in the Mixed Crop-Livestock (MCL) farms, in which livestock and vegetables grown closely in the same facility, is cross-contamination of zoonotic bacterial pathogens especially Salmonella. To investigate the distribution of Salmonella serovars in MCL and their products, a total of 1287 pre-harvest samples from various farms and 1377 post-harvest samples from retail supermarkets in Maryland and Washington D.C. areas were collected and analysed. Atotal of 315 Salmonella isolates were recovered, with 17.44% and 5.88%, from MCL and conventional farms samples (P < 0.001). At post-harvest level, the prevalence of Salmonella was 30.95%, 19.83%, and 8.38% in chicken meat (P < 0.001) from farmers, organic, and conventional retail markets respectively, and 16.81% and 6.06% in produce products (P < 0.001) from farmers and organic retail markets, but none from conventional retail markets. From the isolated Salmonella, 34.50% was confirmed S. Typhimurium, followed by S. Heidelberg (10.86%) and S. Enteritidis (9.90%). The overall multi-antibiotic resistance in recovered Salmonella was 23.81% versus 4.55% in conventional and MCL farms (P = 0.004) and 66.67% versus 7.76% in conventional and farmers markets (P < 0.001). Overall the data reveals higher Salmonella risks in MCL farms' environment and their products sold in farmers markets and warrants taking necessary measures to limit Salmonella transmission.

Developments in detection and determination of aflatoxins

Since the discovery of aflatoxins in the 1960s, much research has focused on detecting the toxins in contaminated food and feedstuffs in the interest of public safety. Most traditional detection methods involved lengthy culturing and/or separation techniques or analytical instrumentation and complex, multistep procedures that required destruction of samples for accurate toxin determination. With more regulations for acceptable levels of aflatoxins in place, modern analytical methods have become quite sophisticated, capable of achieving results with very high precision and accuracy, suitable for regulatory laboratories and for post-harvest sample testing in developed countries. Unfortunately, many countries around the world that are affected by the aflatoxin problem do not have ready access to high performance liquid chromatography and mass spectrometry instrumentation and require alternate, readily available and simple detection methods that may be used by small holdings farmers in developing countries. This paper presents an overview of the existing detection and/or determination methods for aflatoxins. The traditional, quantitative, chemically-based analytical strategies for detecting aflatoxins in maize and their evolution to the modern instrumentation routinely used in developed countries are reviewed. Additionally, novel, more streamlined, user-friendly and in some instances, non-destructive, methods that may be useful for semi-quantitative or qualitative, quick-screening of contaminated maize samples appropriate also for use in developing countries, are discussed.

Perforation of Acellular Dermal Matrices Increases the Rate of Cellular Invasion

BACKGROUND: There are several commercially available acellular dermal matrices (ADM), whose properties vary according to their proprietary manufacturing processes. Survival and durability of any of these ADM depends on effective host cellular invasion and neovascularization. As cellular invasion and vascularization are crucial for ADM incorporation and survival, interventions that could expedite this process should be explored. We sought to quantitatively determine whether perforating ADM scaffolds would result in more rapid host cell invasion in a murine model of graft incorporation.1-5 METHODS: 6mm Strattice™ and Xenmatrix™ scaffolds were created using a biopsy punch and perforated with a 26G needle, resulting in an evenly distributed “spoke and wheel” pattern of 1 perforation/1mm2 of scaffold surface area. Biomechanical testing was performed on perforated and non-perforated samples using a MTS Criterion™ Universal Test Systems machine. Scaffolds were implanted subcutaneously in the dorsa of C57BL6 mice and harvested after 14 and 28 days. Representative sections from post-harvest samples were stained for DAPI (4’, 6-Diamidino-2-Phenylindole) and imaged. Scaffolds were divided into 4 layers of 50 microns with increasing depth, and cell density was calculated using ImageJ. Densities were plotted according to layer depth, yielding an exponential decay graph. Exponential regression equations were then created and used to determine an “invasion coefficient.” Higher invasion coefficients correspond with increased degrees of cellular invasion in each ADM. RESULTS: Biomechanical testing of perforated Strattice™ and Xenmatrix™ demonstrated similar tensile strengths and failure forces when compared with their respective non-perforated samples. After 14 days, perforated Strattice™ exhibited a higher invasion coefficient when compared with non-perforated Strattice™ (0.526 vs. 0.408). Similarly, at our 14-day time-point, the invasion coefficient for perforated Xenmatrix™ was also higher when compared to non-perforated Xenmatrix™ (0.466 vs. 0.378). This trend continued at 28 days with a higher invasion coefficient seen in perforated Xenmatrix™ compared with non-perforated Xenmatrix™ (0.474 vs. 0.395). CONCLUSION: We have demonstrated that perforation of ADM increases the rate of cellular invasion after both 14 and 28 days. Biomechanical testing revealed that perforating ADM did not significantly diminish its tensile strength. These findings suggest that incorporating perforations into the fabrication of ADM may significantly improve scaffold cellular invasion and decrease the time to neovascularization and incorporation. It can also lead to decreased risk of seroma and infection, drastically decreasing patient morbidity.

Analytical Methods Applied to Assess the Effects of Gamma Irradiation on Color, Chemical Composition and Antioxidant Activity of Ginkgo biloba L

The extracts from the leaves of Ginkgo biloba are widely used in medicines and food supplements in order to overcome different health problems. To provide decontamination, irradiation is a safe and effective technique, particularly suitable to be integrated in quality control of the postharvest samples. In this study, different analytical methods were applied to assess the effects of gamma irradiation (1 and 10 kGy) in G. biloba color, chemical composition and antioxidant properties. Irradiation preserved macronutrients, fatty acids, γ- and δ-tocopherols, fructose, trehalose, quinic and shikimic acids. In particular, 1 kGy protected α-tocopherol, oxalic and malic acids contents, while 10 kGy decreased α-tocopherol, glucose, sucrose, oxalic and malic acids level. Nevertheless, this dose was the most effective for antioxidant activity. Overall, 1 kGy would be the recommended dose to maintain nutritional profile of G. biloba, protect specific molecules and also increase antioxidant activity of infusion and methanolic extracts prepared from its leaves.