scholarly journals Microbiological and Chemical Quality of Portuguese Lettuce—Results of a Case Study

Foods ◽  
2020 ◽  
Vol 9 (9) ◽  
pp. 1274
Author(s):  
Catarina Ferreira ◽  
Filipa Lopes ◽  
Reginaldo Costa ◽  
Norton Komora ◽  
Vânia Ferreira ◽  
...  
Keyword(s):  
Fruits And Vegetables ◽  
Organophosphorus Pesticides ◽  
Indicator Organisms ◽  
Salmonella Spp ◽  
Chemical Safety ◽  
Limit Of Quantification ◽  
Wide Range ◽  
Maximum Residue Levels ◽  
Yeasts And Molds

In addition to environmental pollution issues, social concerns about the sustainability, safety, and quality of conventionally grown fruits and vegetables have been increasing. In order to evaluate if there were any microbiological differences between samples of organic and conventional lettuce, a wide range of parameters were tested, including pathogens and indicator organisms: the enumeration of Escherichia coli; the detection of Salmonella spp.; the detection/enumeration of Listeria monocytogenes; the enumeration of lactic acid bacteria, Pseudomonas spp. yeasts and molds, and Enterobacteriaceae. This study also evaluated the chemical safety of the lettuce samples, quantifying the nitrate concentration and 20 pesticides (14 organochlorine and 6 organophosphorus pesticides). Significant differences (p < 0.05) between the conventional and organic samples were only detected for the counts of total microorganisms at 30 °C. Pathogens were absent in all the samples. The analytical method, using the quick, easy, cheap, effective, rugged, and safe (QuEChERS) approach for pesticide extraction, was suitable for detecting the targeted analytes; the limit of quantification (LOQ) was between 0.6 and 1.8 µg/kg (lower than the Maximum Residue Levels (MRLs) established by EU legislation). In three organic lettuce samples, one organochlorine pesticide (α-HCH) was observed below the MRLs. For the samples analyzed and for the parameters investigated, except for the total mesophilic counts, the organic and conventional lettuces were not different.

Detection of Salmonella in Shellfish Grown in Polluted Seawater

1993 ◽  
Vol 27 (3-4) ◽  
pp. 41-44 ◽  
Author(s):  
R. Kfir ◽  
J. S. Burger ◽  
G. K. Idema
Keyword(s):  
South African ◽  
Microbial Quality ◽  
Indicator Organisms ◽  
Faecal Coliforms ◽  
Salmonella Spp ◽  
Quality Of Water ◽  
Wide Range ◽  
Surrounding Seawater ◽  
Poor Relationship

Three bays along the South African coast were studied for the presence of Salmonella spp in seawater, effluent and stormwater discharges into the bays and in shellfish harvested at the same sites. The microbial quality of water and shellfish samples was studied using faecal coliforms and enterococci as indicators of pollution. A combination of Rappaport-Vassiliadis enrichment broth and bismuth sulphite agar was found to provide the best enumeration method for Salmonella spp in samples from a wide range of origins. A poor relationship between levels of indicator organisms and the presence of Salmonella spp was observed at both low and high densities of indicators. A correlation between the presence of Salmonella spp in shellfish and surrounding seawater was frequently found and in most instances Salmonella contamination could be traced to discharges in the vicinity. The findings of this study question the suitability of faecal coliform limits as guidelines for microbial quality of shellfish and shellfish harvesting grounds. Most seawater sites did not comply with the recommended indicator limits. Salmonella spp were detected in seawater and shellfish samples which were free of faecal coliforms.

Principles for construction of bioluminescent enzyme biotests for analysis of complex media

2019 ◽  
Vol 485 (2) ◽  
pp. 229-233
Author(s):  
V. P. Kalyabina ◽  
E. N. Esimbekova ◽  
I. G. Torgashina ◽  
K. V. Kopylova ◽  
V. A. Kratasyuk
Keyword(s):  
Fruits And Vegetables ◽  
Rapid Assessment ◽  
Test System ◽  
Maximum Sensitivity ◽  
Toxic Chemicals ◽  
Complex Media ◽  
Luminescent Bacterium ◽  
Chemical Safety ◽  
Minimal Impact

We formulated the principles of designing bioluminescent enzyme tests for assessing the quality of complex media which consist in providing the maximum sensitivity to potentially toxic chemicals at a minimal impact of uncontaminated complex media. The developed principles served as a basis for designing a new bioluminescent method for an integrated rapid assessment of chemical safety of fruits and vegetables which is based on using the luminescent bacterium enzymes (NAD(P)H:FMN oxidoreductase and luciferase) as a test system.

scholarly journals The Survey of Microbial Quality of the Dry Sample, Extract and Brewing of some Medicinal Plants

2014 ◽  
Vol 6 (4) ◽  
pp. 478-482
Author(s):  
Razieh VALIASILL ◽  
Majid AZIZI ◽  
Maasome BAHREINI ◽  
Hossein AROUIE
Keyword(s):  
Medicinal Plants ◽  
Pathogenic Bacteria ◽  
Agar Medium ◽  
Total Count ◽  
Plate Count ◽  
Microbial Quality ◽  
Salmonella Spp ◽  
E Coli ◽  
Wide Range

Medicinal plants may be exposed to a wide range of microbial contamination during pre- and post- harvest stages and they can present high microbial counts. In this study, the microbial quality of 44 samples of dry herbs namely: mint (Menthaspp.), lemon balm (Melissa officinalis), summer savory (Satureja hortensis), zataria (Zataria multiflora), Indian valerian (Valeriana wallichii), their brewing and extracts were analyzed. Total count using plate count agar medium (PCA), coliform count by Violet Red Bile Agar (VRBL), Enterobacteriacea by Violet Red Bile Glucose (VRBG) were evaluated. Medium Baird-Parker agar (BP) medium and Tryptone Bile X-Gluc (TBX) medium were used for the isolation and enumeration of Staphylococcus aurous and E. coli spp. respectively. Furthermore, Xylose Lysine Deoxycholate agar medium (XLD) and Bismuth Sulfite Agar medium(BSA) were used for detection of Salmonella spp. Fungal and mold contamination was assessed using yeast extract glucose chloramphenicol agar. The results showed that the contamination of the samples with total count (100%) and Enterobacteriaceae (85%), total coliform (83%), mold and yeast (98%) and E. coli ssp. (2.27) were detected, including in the study samples the absence of pathogenic bacteria like Staphylococcus aurous, Salmonella spp. Moreover, the extract had a lower microbial load in comparison to dry herb samples. Also, the lowest and the highest of contamination rates were observed for Indian valerian and zataria, respectively. According to the results, there is a need to control the environmental conditions and improve hygiene in the production process; even more, it is recommended to choose a suitable decontamination method for disinfection during packing medicinal plants and during post-packing manipulation and transport.

scholarly journals Marine Macroalgae, a Source of Natural Inhibitors of Fungal Phytopathogens

2021 ◽  
Vol 7 (12) ◽  
pp. 1006
Author(s):  
Tânia F. L. Vicente ◽  
Marco F. L. Lemos ◽  
Rafael Félix ◽  
Patrícia Valentão ◽  
Carina Félix
Keyword(s):  
Fruits And Vegetables ◽  
Antimicrobial Agents ◽  
Industrial Applications ◽  
Marine Macroalgae ◽  
In Planta ◽  
Lipophilic Compounds ◽  
Wide Range ◽  
Fungal Phytopathogens

Fungal phytopathogens are a growing problem all over the world; their propagation causes significant crop losses, affecting the quality of fruits and vegetables, diminishing the availability of food, leading to the loss of billions of euros every year. To control fungal diseases, the use of synthetic chemical fungicides is widely applied; these substances are, however, environmentally damaging. Marine algae, one of the richest marine sources of compounds possessing a wide range of bioactivities, present an eco-friendly alternative in the search for diverse compounds with industrial applications. The synthesis of such bioactive compounds has been recognized as part of microalgal responsiveness to stress conditions, resulting in the production of polyphenols, polysaccharides, lipophilic compounds, and terpenoids, including halogenated compounds, already described as antimicrobial agents. Furthermore, many studies, in vitro or in planta, have demonstrated the inhibitory activity of these compounds with respect to fungal phytopathogens. This review aims to gather the maximum of information addressing macroalgae extracts with potential inhibition against fungal phytopathogens, including the best inhibitory results, while presenting some already reported mechanisms of action.

A Study of Microbial Quality of Vacuum Packaged, Sliced Bologna1

1978 ◽  
Vol 41 (10) ◽  
pp. 811-815 ◽  
Author(s):  
D. C. PARADIS ◽  
M. E. STILES
Keyword(s):  
Pathogenic Bacteria ◽  
Microbial Load ◽  
Coliform Bacteria ◽  
Microbial Quality ◽  
Indicator Organisms ◽  
Large Numbers ◽  
Wide Range ◽  
Contrast Group ◽  
Group D

A study of 113 samples of vacuum packaged sliced bologna offered for sale in the retail marketplace revealed a wide range of total microbial loads. The pH was not closely related with age or microbial load, within the manufacturers' expected shelf-life of the product. Approximately 55% of old samples had pH &gt;6.0, and pH was influenced by manufacturer. Confirmed coliform bacteria were detected in 5% of samples, but Escherichia coli was absent (&lt;3/10g). In contrast, group D streptococci were present, sometimes in large numbers, depending on manufacturer. Potentially pathogenic bacteria, including Clostridium perfringens (&gt;10/g), coagulase positive Staphylococcus aureus (&gt;25/g) and Salmonella (in 25 g of sample) were generally not detected. Only one sample contained &gt;25 S. aureus/g. No relationship was observed between total microbial load and indicator organisms or pathogenic bacteria.

scholarly journals Plasticulture: Diffusion of Plastic Materials in the Agricultural Sector

2019 ◽  
Vol 56 (4) ◽  
pp. 730-734
Author(s):  
Valentina ConstanȚa Tudor ◽  
DragoȘ Ion Smedescu ◽  
Gina Fîntîneru ◽  
Alexandru Fintineru ◽  
Alina Marcuta ◽  
...  
Keyword(s):  
Everyday Life ◽  
Agricultural Production ◽  
Fruits And Vegetables ◽  
Agricultural Sector ◽  
Raw Materials ◽  
Synthetic Materials ◽  
Plastic Materials ◽  
Wide Range ◽  
Plastic Industry

For more than half a century, the use of plastic in agriculture has given farmers opportunities for growing fruits and vegetables regardless of the season, and at the same time achieving better quality compared to open-field cultivation. The use of plastics, through various specific techniques, helps reduce the consumption of various resources such as water, energy, fertilizers or pesticides.We could say that without these plastics a significant amount of cultivated fruits and vegetables could not be harvested in early conditions and could not be preserved and conditioned in controlled parameters.Plastic is a very important material for economy but also in everyday life. The use of plastic in agriculture has increased from year to year, thus contributing to both the increase of agricultural production and the improvement of the quality of food.Plastics are a wide range of synthetic or semi-synthetic materials that are used for various purposes. In the plastic industry, are used raw materials, such as cellulose, coal, natural gas, salt and, of course, crude oil. Plastics are extremely versatile materials and are ideal for a wide range of applications for industry as well as for consumers.

scholarly journals Comparative analysis of nitrate content in fruit and vegetable products by HPLC

2019 ◽  
pp. 101-104
Author(s):  
S. V. Koptsev ◽  
S. V. Glazkov
Keyword(s):  
Nitrate Content ◽  
Fruit And Vegetable ◽  
Mass Consumption ◽  
Vegetable Products ◽  
Wide Range ◽  
Maximum Residue Levels ◽  
Quality Of Food ◽  
Residue Levels ◽  
Retail Chains

Relevance. The quality of food products in Russia and delivered to retail chains for mass consumption is currently one of the most important food safety priorities.Methods. The article contains the results of studies of nitrate content in fruit and vegetable products during 2018-2019 period, obtained from VNIITeK laboratory, comparisons were made with the permissible level of Maximum residue levels (MRL) for nitrate, which are set in Technical regulation TR TS 021/2011. Totally, 252 samples were studied, for the period from January 2018 to April 2018 inclusive 2019.Results. The nitrate content was determined by liquid chromatography. It was shown, that content of nitrate ions in fruit and vegetable products varies in a wide range, depending on the selected group, at the same time, the lowest level of nitrate is established in children 's fruit puree, the highest levels are found in tomato sauce. 

Effect of Vacuum-Steam-Vacuum Treatment on Microbial Quality of Whole and Fresh-Cut Cantaloupe†

2006 ◽  
Vol 69 (7) ◽  
pp. 1623-1629 ◽  
Author(s):  
DIKE O. UKUKU ◽  
XUETONG FAN ◽  
MICHAEL F. KOZEMPEL
Keyword(s):  
Fruits And Vegetables ◽  
Vacuum Treatment ◽  
Microbial Quality ◽  
Pseudomonas Spp ◽  
Mesophilic Bacteria ◽  
Log Reduction ◽  
Fresh Cut ◽  
Yeasts And Molds ◽  
Spoilage Microflora

Minimally processed fruits and vegetables have a limited shelf life because of deterioration caused by spoilage microflora and physiological processes. Cutting may increase microbial spoilage of fruits through transfer of microflora on the outer surfaces to the interior tissue. The objectives of this study were to use the vacuum-steam-vacuum (VSV) process to reduce indigenous spoilage microflora on the surface of cantaloupes and to investigate the effects of such treatments on transfer of spoilage microflora from the cantaloupe surface to the fresh-cut melon during rind removal and cutting. Whole cantaloupes were treated in the VSV processor, and fresh-cut pieces prepared from treated and control samples were stored at 5 and 10°C for up to 9 days. Presence and growth of mesophilic bacteria, yeasts and molds, and Pseudomonas spp. were determined in fresh-cut samples during storage. Texture and color (CIE L*, a*, and b*) also were measured during storage. VSV treatment resulted in a 1.0-log reduction of aerobic mesophilic bacteria, a 2.0-log reduction of yeasts and molds, and a 1.5-log reduction of Pseudomonas spp. on cantaloupe surfaces. VSV treatment significantly reduced transfer of yeasts and molds and Pseudomonas spp. from whole cantaloupe surface to fresh-cut pieces during preparation (P &lt; 0.05). Texture and color of the fresh-cut pieces prepared from the VSV-treated whole melons were similar to those of the controls. The results of this study indicate that the use of the VSV process to reduce the surface populations of yeasts and molds and Pseudomonas spp. on whole cantaloupes will reduce subsequent transfer of these microbes to fresh-cut pieces and enhance the microbial quality of the fresh-cut product.

scholarly journals Residue Content of Organophosphorus Pesticides and their Toxic Metabolites in Greenhouse-Grown Tomatoes during Pre-Harvest Interval and Post-Harvest Processing: A Kinetic Study

2020 ◽  
Keyword(s):  
Fruits And Vegetables ◽  
Limit Of Detection ◽  
Organophosphorus Pesticides ◽  
Residue Analysis ◽  
Second Order ◽  
Limit Of Quantification ◽  
Post Harvest ◽  
Best Fitting ◽  
Greenhouse Tomatoes ◽  
Nonlinear Kinetic

Background: Organophosphorus pesticides (OPPs) have a wide application throughout the world and exert adverse effects on human health. Moreover, these chemical compounds are responsible for thousands of deaths per year worldwide. Kinetic and mathematical models could be used to optimize the application of pesticides on fruits and vegetables and monitor their residues. Objectives: The present study aimed to model the dissipation of diazinon and chlorpyrifos in different conditions, such as household conditions (e.g., storage at room and refrigerator temperatures, as well as cooking) and field condition for greenhouse tomatoes. Methods: A multi-residue analysis of diazinon, chlorpyrifos, and their oxon derivatives was established by gas chromatography-tandem mass spectrometry. The limit of quantification (LOQ), recovery, precision, linearity, and the limit of detection (LOD) were evaluated to ensure that the method was able to effectively determine the studied pesticides in the tomato samples. The linear and nonlinear kinetic models were presented for chlorpyrifos and diazinon residues in tomato using zero-order, first-order, and second-order equations. Results: Based on the best fitting models for diazinon in the case of laboratory treatment at the refrigerator, room, and boiling temperatures, the half-lives were calculated as 18.79 days, 11.41 days, and 45.39 min, respectively. The half-life of diazinon was lower than that of chlorpyrifos in both field and laboratory treatments. Conclusion: Modeling the removal of the pesticides indicated that the nonlinear first- and second-order models were the best fitted models for the dissipation of both pesticides in field and post-harvest conditions.

COMBINATORIAL POLYNOMIALLY COMPUTABLE CHARACTERISTICS OF SUBSTITUTIONS AND THEIR PROPERTIES

2020 ◽  
Vol 7 (2) ◽  
pp. 34-41
Author(s):  
VLADIMIR NIKONOV ◽  
◽  
ANTON ZOBOV ◽  
Keyword(s):  
Mathematical Expectation ◽  
Point Of View ◽  
Small Range ◽  
Computational Point ◽  
Wide Range ◽  
Bijective Function ◽  
The Difference ◽  
Element Base ◽  
Selection Of

The construction and selection of a suitable bijective function, that is, substitution, is now becoming an important applied task, particularly for building block encryption systems. Many articles have suggested using different approaches to determining the quality of substitution, but most of them are highly computationally complex. The solution of this problem will significantly expand the range of methods for constructing and analyzing scheme in information protection systems. The purpose of research is to find easily measurable characteristics of substitutions, allowing to evaluate their quality, and also measures of the proximity of a particular substitutions to a random one, or its distance from it. For this purpose, several characteristics were proposed in this work: difference and polynomial, and their mathematical expectation was found, as well as variance for the difference characteristic. This allows us to make a conclusion about its quality by comparing the result of calculating the characteristic for a particular substitution with the calculated mathematical expectation. From a computational point of view, the thesises of the article are of exceptional interest due to the simplicity of the algorithm for quantifying the quality of bijective function substitutions. By its nature, the operation of calculating the difference characteristic carries out a simple summation of integer terms in a fixed and small range. Such an operation, both in the modern and in the prospective element base, is embedded in the logic of a wide range of functional elements, especially when implementing computational actions in the optical range, or on other carriers related to the field of nanotechnology.

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