Differential microbiota shift on whole romaine lettuce subjected to source or forward processing and on fresh-cut products during cold storage.

Romaine lettuce in the U.S. is primarily grown in California or Arizona and either processed near the growing regions (source processing) or transported long distance for processing in facilities serving distant markets (forward processing). Recurring outbreaks of Escherichia coli O157:H7 implicating romaine lettuce in recent years, which sometimes exhibited patterns of case clustering in Northeast and Midwest, have raised industry concerns over the potential impact of forward processing on romaine lettuce food safety and quality. In this study, freshly harvested romaine lettuce from a commercial field destined for both forward and source processing channels was tracked from farm to processing facility in two separate trials. Whole-head romaine lettuce and packaged fresh-cut products were collected from both forward and source facilities for microbiological and product quality analyses. High-throughput amplicon sequencing targeting16S rRNA gene was performed to describe shifts in lettuce microbiota. Total aerobic bacteria and coliform counts on whole-head lettuce and on fresh-cut lettuce at different storage times were significantly (p < 0.05) higher for those from the forward processing facility than those from the source processing facility. Microbiota on whole-head lettuce and on fresh-cut lettuce showed differential shifting after lettuce being subjected to source or forward processing, and after product storage. Consistent with the length of pre-processing delays between harvest and processing, the lettuce quality scores of source-processed romaine lettuce, especially at late stages of 2-week storage, was significantly higher than of forward-processed product (p < 0.05).

[Spatial Distribution of Aerobic Bacteria, Sources and Risks of Nitrogen and Phosphorus in Taihu Lake Sediments].

The release of nitrogen and phosphorus from sediments into lake water will exacerbate the eutrophication of lakes and endanger ecological safety and human health. Microorganisms are indispensable in nitrogen and phosphorus conversion, and accurate analysis of the distribution characteristics and sources of nitrogen and phosphorus in sediments as well as their relationship with microorganisms is an important prerequisite for lake eutrophication control. Taking Taihu Lake as the study area, 30 surface sediment samples were collected, and the grain size, pH, organic matter (OM), dissolved organic carbon (DOC), total phosphorus (TP), total nitrogen (TN), nitrate nitrogen (NO3--N), and dissolved organic nitrogen (DON) along with some other index contents were measured and analyzed; accordingly, spatial distribution characteristics were analyzed. While using nutrient agar (NA), the number of aerobic bacteria (AB) was determined by plate counting in the medium. Combined with principal component analysis (PCA) and Pearson correlation analysis, the spatial distribution characteristics and sources of sediments and AB in Taihu Lake were explored. The characteristics of sediment pollution in Taihu Lake were studied using the comprehensive pollution index and the organic pollution index methods. The results revealed that the average sediment indicators of the surface layer of Taihu Lake were as follows:AB was 9.25×104 CFU·g-1, average particle size (MZ) was 17.59 µm, pH was 7.62, ω(OM) was 15.05 g·kg-1, ω(DOC) was 71.60 mg·kg-1, ω(TP) was 598.13 mg·kg-1, ω(TN) was 1113.92 mg·kg-1, ω(NO3--N) was 3.22 mg·kg-1, and ω(DON) was 22.60 mg·kg-1. The comprehensive pollution index (FF) showed that 13% of the Taihu Lake was moderately polluted, while 87% was heavily polluted. Excluding the area in the center of the lake, the southern lake area, and some lakes in the western part of the East Taihu Lake, TN in the rest of the area was moderately and severely polluted. In addition to the heavy pollution of Zhushan Bay, the TP in Taihu Lake was generally at light and moderate pollution. The organic pollution index (OI) showed that the organic pollution of the sediments of Taihu Lake was relatively light, majorly caused by organic nitrogen (ON) pollution. DOC, DON, TN, and OM in Taihu Lake were primarily derived from the influence of aquatic plants, and TP And AB were primarily derived from the influence of the external input of rivers. This research will provide theoretical support for lake eutrophication treatment and also provide new ideas for further analysis of AB to remove nitrogen and phosphorus pollution from sediments.

Evaluation and comparison of the antimicrobial activity of royal jelly - A holistic healer against periodontopathic bacteria: An in vitro study.

CONTEXT: RJ is a natural bee product and is known to have remarkable health benefits. The objective was to evaluate its antimicrobial potential against periodontopathic bacteria and compare the same with chlorhexidine. AIMS: The aim was to evaluate and compare the antimicrobial activity of royal jelly (RJ) with chlorhexidine against the periodontopathic bacteria (aerobic and anaerobic) in subgingival plaque. MATERIALS AND METHODS: Subgingival plaque samples of 15 chronic periodontitis patients were taken, and clinical parameters were evaluated. Inhibitory effect of RJ and chlorhexidine was investigated "in vitro" on the growth of aerobic and anaerobic bacteria by colony count, minimum inhibitory concentration, and minimum bactericidal concentration (MBC) by the method of serial broth dilution. STATISTICAL ANALYSIS USED: ANOVA statistical analysis was used in this study. RESULTS: Subgingival anaerobic bacteria predominate (colony-forming unit). Chlorhexidine is more sensitive in inhibiting aerobic and anaerobic bacteria (at concentration 50 µg/100 µl). A higher concentration of RJ is required to have an inhibitory effect. MBC of chlorhexidine shows no growth on blood agar plates, whereas minimum bacterial growth is seen around the RJ. CONCLUSIONS: Chlorhexidine (gold standard) has a higher inhibitory effect in the case of chronic periodontitis; however, RJ can also be used as an alternative but at higher concentration and lesser dilution. Evaluation of the quality, quantity and the biological activity of RJ is a necessity and must be done before its "in vivo" application.

Characteristics of proteolytic microorganisms and their effects on proteolysis in total mixed ration silages of soybean curd residue.

OBJECTIVE: The objective of this study was to isolate proteolytic microorganisms and evaluate their effects on proteolysis in total mixed ration (TMR) silages of soybean curd residue. METHODS: TMRs were formulated with soybean curd residue, alfalfa or Leymus chinensis hay, corn meal, soybean meal, a vitamin-mineral supplement, and salt in a ratio of 25.0:40.0:30.0:4.0:0.5:0.5, respectively, on a basis of dry matter (DM). The microbial proteinases during ensiling were characterized, the dominate strains associated with proteolysis were identified, and their enzymatic characterization were evaluated in alfalfa (A-TMR) and Leymus chinensis (L-TMR) TMR silages containing soybean curd residue. RESULTS: Both A-TMR and L-TMR silages were well preserved, with low pH and high lactic acid concentrations. The aerobic bacteria and yeast counts in both TMR silages decreased to about 105 cfu g-1 FM (Fresh matter) and below the detection limit, respectively. The lactic acid bacteria count increased to 109 cfu g-1 FM. The total microbial proteinases activities reached their maximums during the early ensiling stage and then reduced in both TMR silages with fermentation prolonged. Metalloproteinase was the main proteinase when the total proteinases activities reached their maximums, and when ensiling terminated, metallo and serine proteinases played equally important parts in proteolysis in both TMR silages. Strains in the genera Curtobacterium and Paenibacillus were identified as the most dominant proteolytic bacteria in A-TMR and L-TMR, respectively, and both their proteinases were mainly with metalloproteinase characteristics. In the latter ensiling phase, Enterococcus faecium strains became the major sources of proteolytic enzymes in both TMR silages. Their proteinases were mainly of metallo and serine proteinases classes in this experiment. CONCLUSION: Proteolytic aerobic bacteria were substituted by proteolytic lactic acid bacteria during ensiling, and the microbial serine and metallo proteinases in these strains played leading roles in proteolysis in TMR silages.

Zinc phosphate-based nanoparticles as a novel antibacterial agent: in vivo study on rats after dietary exposure.

BACKGROUND: Development of new nanomaterials that inhibit or kill bacteria is an important and timely research topic. For example, financial losses due to infectious diseases, such as diarrhea, are a major concern in livestock productions around the world. Antimicrobial nanoparticles (NPs) represent a promising alternative to antibiotics and may lower antibiotic use and consequently spread of antibiotic resistance traits among bacteria, including pathogens. RESULTS: Four formulations of zinc nanoparticles (ZnA, ZnB, ZnC, and ZnD) based on phosphates with spherical (ZnA, ZnB) or irregular (ZnC, ZnD) morphology were prepared. The highest in vitro inhibitory effect of our NPs was observed against Staphylococcus aureus (inhibitory concentration values, IC50, ranged from 0.5 to 1.6 mmol/L), followed by Escherichia coli (IC50 0.8-1.5 mmol/L). In contrast, methicillin resistant S. aureus (IC50 1.2-4.7 mmol/L) was least affected and this was similar to inhibitory patterns of commercial ZnO-based NPs and ZnO. After the successful in vitro testing, the in vivo study with rats based on dietary supplementation with zinc NPs was conducted. Four groups of rats were treated by 2,000 mg Zn/kg diet of ZnA, ZnB, ZnC, and ZnD, for comparison two groups were supplemented by 2,000 mg Zn/kg diet of ZnO-N and ZnO, and one group (control) was fed only by basal diet. The significantly higher (P < 0.05) Zn level in liver and kidney of all treated groups was found, nevertheless Zn NPs did not greatly influence antioxidant status of rats. However, the total aerobic and coliform bacterial population in rat feces significantly decreased (P < 0.05) in all zinc groups after 30 d of the treatment. Furthermore, when compared to the ZnO group, ZnA and ZnC nanoparticles reduced coliforms significantly more (P < 0.05). CONCLUSIONS: Our results demonstrate that phosphate-based zinc nanoparticles have the potential to act as antibiotic agents.

A clinical study on Virechana Karma (therapeutic purgation) over the gut flora with special reference to obesity.

BACKGROUND: Altered gut flora is associated with the pathogenesis of both intestinal and extra­intestinal disorders. Aetiology of obesity is associated with mechanisms such as short chain fatty acid production, stimulation of hormones, chronic low­grade inflammation, lipoprotein and bile acid metabolism and increased endocannabinoid. Receptor system tone have been suggested to explain the role of gut microbiota of obesity. The Panchakarma (Ayurvedic purification methods) claims the management of metabolic disorders hence this work provides the target specific evidence for the clinical studies. The proposed project is aimed to explore the particular molecular mechanism and, to make this therapy more evidence based. Hence, it was hypothesized that Panchakarma­based intervention such as Virechana Karma (therapeutic purgation) may influence microbiota and help in the management of the obesity. MATERIALS AND METHODS: The study was conducted to explore the effect of Virechana Karma over the gut flora; therefore, total of 19 patients with Madhyama Koshtha diagnosed with obesity were included and received the intervention. Before and after Virechana, a stool sample was collected and processed for the enterobacterial repetitive intergenic consensus ­polymerase chain reaction to find the changes over the facultative aerobic bacteria. RESULTS: It was found that Virechana is effective in the management of the obesity as it helps to reduce colonization of aerobic bacteria. After Virechana and after follow­up also, it showed the correction of the gut flora dysbiosis, thus initiated the weight loss mechanism in the body, resulting in diminution in the signs and symptoms of obesity. CONCLUSION: Virechana is effective in the management of the obesity due to reduction in the Escherichia coli colonization and is effective over the gut flora dysbiosis.

Inactivation of Salmonella Typhimurium on red chili peppers by treatment with gaseous chlorine dioxide followed by drying.

Chili pepper (Capsicum annuum L.) powder and other powdered spices containing chili peppers are occasionally contaminated with foodborne pathogens. We applied chlorine dioxide (ClO2) gas treatment to chili peppers prior to drying to inactivate Salmonella Typhimurium. Chili peppers inoculated with S. Typhimurium were exposed to ClO2 gas generated from 0.77 mL of aqueous ClO2 for 6 h at 25 °C and 100% relative humidity, followed by air drying at 55 °C for up to 24 h. Populations of S. Typhimurium and total aerobic bacteria (TAB) on peppers, chromaticity values, and moisture content were determined after various treatment times. S. Typhimurium (ca. 5.6 log cfu/g) was reduced to <0.7 log cfu/g of peppers treated with ClO2 gas for 0.5 h at 25 °C, but was detected by enrichment (>1 cfu/10.8 g) after treatment for 4 h. The pathogen was not detected after treatment with ClO2 gas for 6 h. S. Typhimurium did not decrease significantly (P > 0.05) on peppers exposed to air at 25 °C for 6 h, but rapidly decreased to 1.6 log cfu/g after subsequent drying for 6 h at 55 °C. The initial number of TAB (ca. 6.5 log cfu/g) decreased to 1.4 log cfu/g after treatment with ClO2 gas for 0.5 h and was less than the detection limit (0.7 log cfu/g) after 2 h. TAB counts were not reduced by treating peppers with air for 6 h, but decreased to <0.7 log cfu/g after subsequent drying for 24 h at 55 °C. The lightness (L value) of treated and untreated chili peppers did not change during drying, but redness (a value) and yellowness (b value) decreased. Results showed that treatment of chili peppers containing S. Typhimurium (5.6 log cfu/g) with ClO2 gas for 6 h prior to drying at 55 °C reduced the population to < 1 cfu/10.8 g.

Phosphogypsum biotransformation by aerobic bacterial flora and isolated Trichoderma asperellum from Tunisian storage piles.

Aerobic microorganisms able to grow on phosphogypsum (PG), characterized by heavy metals accumulation and high acidity were investigated by enrichment cultures. The PG was used at different concentrations, varying from 20 to 200 g/L in the enrichment culture medium supplemented with compost and Tamarix roots. This treatment reduced COD and heavy metals PG concentration. An efficient isolated fungus, identified by molecular approach as Trichoderma asperellum, was able to grow on PG as the sole carbon and energy sources at the different experimented concentrations, and to increase the culture media pH of the different PG concentrations used to 8.13. This fact would be the result of alkaline compound released during the fungus PG solubilization. Besides, the heavy metals and COD removal exceeded 52% after 7 days culture. At 200 g/LPG concentration, the experimented strain was able to reduce COD by 52.32% and metals concentrations by 73% for zinc, 63.75% for iron and 50% for cadmium. This exhibited the T. asperellum efficiency for heavy metals accumulation and for phosphogypsum bioremediation.

Evaluación del potencial antibacterial in vitro de Croton lechleri frente a aislamientos bacterianos de pacientes con úlceras cutáneas / In vitro evaluation of antibacterial potential of Croton lechleri against bacterial isolates from patients with skin ulcers

Esta investigación tuvo como objetivo la evaluación del potencial antibacterial in vitro de Croton lechleri frente a aislamientos bacterianos aeróbicos de pacientes con úlceras cutáneas del Sanatorio de Agua de Dios, Cundinamarca, Colombia. La metodología utilizada incluyó el aislamiento e identificación de los aislamientos bacterianos utilizando el sistema automatizado BBL-CrystalTM. Para la evaluación de la susceptibilidad antimicrobiana in vitro, se realizaron pruebas de difusión en disco, dilución en agar y difusión en pozo, métodos estandarizados por The Clinical and Laboratory Standards Institute (CLSI); usando como sustratos el extracto etanólico y de éter de petróleo de Croton lechleri. Se obtuvieron siete aislamientos bacterianos a partir de las úlceras cutáneas de pacientes del sanatorio, el estudio también incluyó ensayos con cepas de referencia ATCC: Staphylococcus aureus (ATCC) y de Escherichia coli (ATCC) como control. En los ensayos de sensibilidad antimicrobiana in vitro, se evidencio que los extractos de Croton lechleri fueron efectivos frente a la mayoría de aislamientos bacterianos del estudio, siendo el extracto etanólico el de mayor potencial antibacterial y la técnica de difusión en pozo la que presento mejor sensibilidad y reproducibilidad.

This study evaluated the in vitro antibacterial potential of Croton lechleri against aerobic bacterial isolates from patients with skin ulcers from Agua de Dios Sanitarium, (Cundinamarca, Colombia). Bacterial isolates were isolated and identified using the BBL-CrystalTM automated system. In vitro antimicrobial susceptibility was evaluated through disk diffusion, agar dilution and well diffusion, using standardized methods from the Clinical and Laboratory Standards Institute (CLSI). Ethanol extract and petroleum ether from Croton lechleri were used as substrates. Bacterial isolates were obtained from skin ulcers of patients in the hospital. ATCC reference strains were included in the assays as controls: Staphylococcus aureus (ATCC) and Escherichia coli (ATCC). The antimicrobial sensitivity tests demonstrated that Croton lechleri extracts were effective against almost all strains included in this study. Ethanol extract showed the greater antibacterial potential. The technique that showed the best sensitivity and reproducibility in vitro was the diffusion well.

A Clinical Study on the Effect of a Cream Containing Ramulus Mori Extract and Tea Tree Oil on Acne Vulgaris and Aerobic Skin Flora / 대한피부과학회지

BACKGROUND: The exact role of aerobic bacteria in the pathogenesis of acne remains controversial but several reports showed that these microorganisms were important in the development of acne lesions and affected the severity of acne by being involved in the inflammatory process. There were several attempts to improve and prevent the acne lesions by using soap or cosmetics containing anti-microbial agents. OBJECTIVE: The purpose of this study was to compare the sebum secretion rates and the number of aerobic bacteria in acne patients after 4 weeks trial of RT cream containing 0.1% tea-tree oil and 0.01% Ramulus mori extract. METHODS: We studied 10 normal controls and 20 acne patients. Sebum secretion was measured by Sebumeter. Clinical efficacy was evaluated by comparing numbers of non-inflammatory and inflammatory lesions. Aerobic bacteria was also cultured from control group and acne patients group before and after RT cream use. RESULTS: Sebum secretion rates in acne patients were higher than those in control, but not statistically significant. Total number of aerobic bacteria in acne patients was higher than that in control (p<0.05). The aerobic bacteria consisted of coagulase negative Staphylococcus, Streptococcus sp., S. aureus in both acne patients and control. After 4 weeks, the number of inflammatory lesions had decreased (p<0.05%). In addition, the number of aerobic bacteria showed the tendency of decrease after RT cream use. CONCLUSION: RT cream consisting of 0.1% tea tree oil and 0.01% Ramulus mori extract was found to be effective and safe for acne patients with especially inflammatory lesions.