Antimicrobial Substances Research Articles

Indoor Space Disinfection Effect and Bioactive Components of Chamaecyparis obtusa Essential Oil

Chamaecyparis obtusa (Siebold & Zucc.) Endl. (Cupressaceae) is known to produce a variety of antimicrobial substances. In the present study, components of three lots of essential oil from C. obtusa were analyzed by GCMS. It was confirmed that thujopsene and pinene were common markers. In addition, we report indoor space disinfectant effects of products containing C. obtusa essential oil (PO100, PO500, PO1000). It was confirmed that PO100 and PO500 could effectively remove airborne microorganisms in indoor spaces. Results of our study suggest that C. obtusa essential oil is effective in reducing contamination by infectious microorganisms in confined spaces.

Salivary physicochemical characteristics and antimicrobial human peptide among Indian children with dental caries.

Salivary innate defenses encompass mechanical cleaning, calcium phosphate salts and fluoride ion reduction of enamel dissolution rate, buffering capacity and neutralizing capacity, and antibacterial properties employing antimicrobial substances like antimicrobial peptides,agglutins,lactoferrin, lactoperoxidase, lysozyme and immuno globulins. Antimicrobial peptides play a key role in the initial defensive responses that make up innate immunity. The aim of this study was to assess the relationship between salivary physicochemical characteristics like buffering capacity, pH, flow rate, and concentrations antimicrobial human peptide like HBD-3, HNP1-3 and LL-37 and caries activity in young children. Before to collecting the samples, informed permission papers were gathered and completed by the children's legal guardians or parents. There was significant correlation showing reduced caries activity on increased concentrations of HNP1-3. When there was analysis of correlation of CAS with LL-37 concentrations then the p value vas 0.002 showing the correlation was significant. There is significant relationship between salivary physicochemical characteristics like buffering capacity, pH, flow rate, and concentrations antimicrobial human peptide like HBD-3, HNP1-3 and LL-37 and caries activity in young children.

Probiotics Based on Lactic Acid Bacteria for Aquaculture

Aquaculture (especially fish farming) provides billions of people with nutrients: amino acids, vitamins, minerals, and proteins. Aquaculture of commercial species (rainbow trout, common carp, grass carp, pacific white-legged shrimp, etc.) are growing rapidly and accounts for about a third of the global fish production. It is a major alternative to reducing wild populations that are unable to meet growing food demand. Lactic acid bacteria (LAB) of the genera Lactococcus, Lactobacillus, Lactiplantibacillus, Enterococcus, Leuconostoc, Pediococcus, Streptococcus, Carnobacterium, and Weissella belong to the normobiota of the gastrointestinal (GI) tract of most fish. They play an important role as they stimulate the synthesis of digestive enzymes, prevent intestinal disorders, improve the immune response of the macroorganism, increase the barrier capacity of the mucous membrane due to the colonization of the fish GI tract, activate the resistance to the development of bacterial and viral infections due to the production of a wide range of antimicrobial substances (bacteriocins, organic acids, hydrogen peroxide, etc.). Therefore, Lactobacilli are classified as potential probiotic strains for aquaculture. The combined use of lactic acid bacteria with feed increases their nutritional value, as microorganisms produce a wide range of digestive enzymes that actively participate in the process of digestion and decomposition of feed, as well as positively affect the growth of individuals and stimulate their reproductive activity, which undoubtedly contributes to the active introduction of commercial probiotics based on LAB strains. As a result of growing aquaculture, there are many problems such as stocking density, infectious diseases, excessive use of antibiotics, water pollution, which can be solved with the help of probiotic lactic acid bacteria. Therefore, the review presents current literature data on the use of lactic acid bacteria strains as probiotic preparations for aquaculture, their species composition, probiotic effect on the host, the mechanism of action of probiotics on aquaculture, and the methods for delivery to the macroorganism.

Functional insights to the development of bioactive material for combating bacterial infections.

The emergence of antibiotic-resistant "superbugs" poses a serious threat to human health. Nanomaterials and cationic polymers have shown unprecedented advantages as effective antimicrobial therapies due to their flexibility and ability to interact with biological macromolecules. They can incorporate a variety of antimicrobial substances, achieving multifunctional effects without easily developing drug resistance. Herein, this article discusses recent advances in cationic polymers and nano-antibacterial materials, including material options, fabrication techniques, structural characteristics, and activity performance, with a focus on their fundamental active elements.

Evaluation of the antimicrobial activity of sodium alginate films integrated with cinnamon essential oil and citric acid on sliced cooked ham

AbstractBio‐based antimicrobial films have been developed using sodium alginate and 6 wt% of cinnamon essential oil (CEO) as a volatile antimicrobial substance and 4 and 6 wt% of citric acid (CA) as a non‐volatile antimicrobial substance. Antimicrobial activity of the films was tested in in vitro tests against Escherichia coli and Listeria innocua by disc diffusion or vapour diffusion assay. Sodium alginate films containing CA exhibited a zone of inhibition between 30.86 ± 2.55 and 45.87 ± 1.90 against E. coli and L. innocua in the disc diffusion assays. Films containing CEO also showed significant antimicrobial activities in the vapour diffusion assays that resulted in a log reduction of 5.3 for E. coli and 3.2 for L. innocua after 6 days. Antimicrobial activities of all films were also tested against L. innocua on sliced cooked ham. Films containing CEO did not prevent the growth of L. innocua inoculated on ham. On the other hand, sodium alginate films with CA fully inhibited the growth of L. innocua on ham during storage at 7.5°C for 12 days resulting in a bacterial count below the detection limit after 12 days. The addition of antimicrobial substances in sodium alginate films resulted in a slight colour change (but significant) and reduced the tensile strength of the films significantly. Adding CA to sodium alginate films increased the moisture content (from 24.81% to 35.41–48.02%) as well as the elongation at break (from 11.3% to 22.6–33.2%) of the films.

Hospital sanitary facilities on wards with high antibiotic exposure play an important role in maintaining a reservoir of resistant pathogens, even over many years

BackgroundHospitals with their high antimicrobial selection pressure represent the presumably most important reservoir of multidrug-resistant human pathogens. Antibiotics administered in the course of treatment are excreted and discharged into the wastewater system. Not only in patients, but also in the sewers, antimicrobial substances exert selection pressure on existing bacteria and promote the emergence and dissemination of multidrug-resistant clones. In previous studies, two main clusters were identified in all sections of the hospital wastewater network that was investigated, one K. pneumoniae ST147 cluster encoding NDM- and OXA-48 carbapenemases and one VIM-encoding P. aeruginosa ST823 cluster. In the current study, we investigated if NDM- and OXA-48-encoding K. pneumoniae and VIM-encoding P. aeruginosa isolates recovered between 2014 and 2021 from oncological patients belonged to those same clusters.MethodsThe 32 isolates were re-cultured, whole-genome sequenced, phenotypically tested for their antimicrobial susceptibility, and analyzed for clonality and resistance genes in silico.ResultsAmong these strains, 25 belonged to the two clusters that had been predominant in the wastewater, while two others belonged to a sequence-type less prominently detected in the drains of the patient rooms.ConclusionPatients constantly exposed to antibiotics can, in interaction with their persistently antibiotic-exposed sanitary facilities, form a niche that might be supportive for the emergence, the development, the dissemination, and the maintenance of certain nosocomial pathogen populations in the hospital, due to antibiotic-induced selection pressure. Technical and infection control solutions might help preventing transmission of microorganisms from the wastewater system to the patient and vice versa, particularly concerning the shower and toilet drainage. However, a major driving force might also be antibiotic induced selection pressure and parallel antimicrobial stewardship efforts could be essential.

Probiotics: Sources, selection and health benefits

Probiotics are defined as “live microorganisms that, when administered in adequate amounts, confer a health benefit on the host”. Nowadays, the probiotic market is growing tremendously by using probiotics especially in foods, dietary supplements and pharmaceutical applications. Sometimes, the consumers get confused between probiotics and non-probiotics. A more precise use of the term “probiotics” will be useful to guide consumers and other stakeholders in differentiating the diverse products on the market. Since efficacy of probiotics is strain specific, the appropriate selection of probiotics is extremely important. This review focuses on discussing the following issues of probiotics including their major sources, selection criteria, health benefits and possible harms. The main selection criteria for probiotics include the following ability to: tolerate into a product at a sufficient level and remain viable throughout the shelf life of the product; withstand transit through a gastrointestinal tract; adhere to intestinal epithelial cells and colonize the lumen of the tract; produce antimicrobial substances against the pathogens and to be harmless to a host associated with the health benefits. The major health benefits of probiotics involve an improvement of intestinal health, an enhancement of the immune response, a prevention/treatment of infectious disease and a prevention/treatment of cancer.

On the features of the correction of intestinal dysbiosis in chronic pancreatitis (literature review)

The aim of the literature review was to analyze the modern approach to the correction of intestinal dysbiosis in patients with chronic pancreatitis, including the one combined with metabolic syndrome, coronary heart disease, and especially bacterial overgrowth syndrome.
 Particular attention is paid to the peculiarities of drug therapy and the pharmacotherapeutic mechanisms of influence of various groups of pro-, pre- and synbiotics on the condition of the intestine, immunity, and inflammatory processes. The requirements for an adequate selection of drugs are considered. They must be useful for the human body; should not cause side effects during long-term use, but should have a minimal ability to translocate from the lumen of the intestine to internal organs; must be resistant to low pH values, the influence of bile acids, and antimicrobial substances produced by endogenous microflora; adhere well to the epithelium of mucous membranes; have a high rate of growth and reproduction in the intestines; and must have a clear physiological, biochemical, and genetic marking. Efficacy criteria are the probiotic effect proven in double-blind placebo-controlled studies. These requirements are met by B. bifidum, Lactobacillus acidophilus, Lactobacillus GG, Lactobacillus fermentum, Strepto(Entero)coccus faecium, Saccharomyces boulardii, which are components of many probiotics.
 Interesting information is provided about the probiotic with level A evidence, called Enterol by the WHO experts: it is a self-eliminating probiotic, each capsule of which contains 250 mg of lyophilized cells of a selective strain of medicinal yeast, Saccharomyces boulardii. It is crucial that the drug prevents the growth of a wide range of pathogenic microorganisms and fungi and promotes their elimination (Clostridium difficile, Clostridium pneumoniae, Staphylococcus aureus, Pseudomonas aeruginosa, Candida crusei, Candida pseudotropical, Candida albicans, Salmonella typhi, Salmonella enteriditis, Escherichia coli, Shigella dysenteriae, Shigella flexneri, Klebsiella, Proteus, Vibrio cholera, Enthamoeba hystolitica, Enterovirus, Rotavirus).

Separation and Identification of an Antimicrobial Substance from Schisandra chinensis Extract against Streptococcus mutans KCCM 40105 Strain.

This study aimed to isolate and identify antibacterial compounds from Schisandra chinensis (S. chinensis) that are effective against the Streptococcus mutans KCCM 40105 strain. First, S. chinensis was extracted using varying concentrations of ethanol, and the resulting antibacterial activity was evaluated. The 30% ethanol extract of S. chinensis showed high activity. The fractionation and antibacterial activity of a 30% ethanol extract from S. chinensis were examined using five different solvents. Upon investigation of the antibacterial activity of the solvent fraction, the water and butanol fractions showed high activity, and no significant difference was found. Therefore, the butanol fraction was chosen for material exploration using silica gel column chromatography. A total of 24 fractions were obtained from the butanol portion using silica gel chromatography. The fraction with the highest antibacterial activity was Fr 7. From Fr 7, thirty-three sub-fractions were isolated, and sub-fraction 17 showed the highest level of antibacterial activity. A total of five peaks were obtained through the pure separation of sub-fraction 17 using HPLC. Peak 2 was identified as a substance exhibiting a high level of antibacterial activity. Based on the results of UV spectrometry, 13C-NMR, 1H-NMR, LC-MS, and HPLC analyses, the compound corresponding to peak number 2 was identified as tartaric acid.

The Behavior of Some Bacterial Strains Isolated from Fallow Deer Compared to Antimicrobial Substances in Western Romania.

(1) Background: The resistance levels of Escherichia coli, Salmonella spp., Pseudomonas spp., Staphylococcus spp., etc., isolated from the nasal cavity and the rectum of Dama dama deer from three hunting grounds in Western Romania were assessed. (2) Methods: The analysis was completed using the diffusimetric method, compliant with CLSI reference standards, and with Vitek-2 (BioMérieux, France), on 240 samples. (3) Results: The results were statistically analyzed (by one-way ANOVA) revealing that in four of the ten E. coli strains isolated from animals, 87.5% (p < 0.001) resistance was found. E. coli strains were resistant to cephalexin (100%); seven strains were resistant to cephalothin and ampicillin; six were resistant to cefquinome and cefoperazone; five were resistant to amoxicillin/clavulanic acid; and four were resistant to ceftiofur. However, E. coli was sensitive to amikacin (100%). The most efficient structures were beta-lactams, amikacin, and imipenem, to which all 47 strains studied (100%) were sensitive, followed by nitrofurantoin, to which 45 strains (95.7%) were sensitive, neomycin, to which 44 strains (93.6%) were sensitive, ceftiofur, to which 43 strains (91.5%) were sensitive, and trimethoprim/sulfamethoxazole and marbofloxacin, to which 42 strains (89.4%) were sensitive. (4) Conclusions: In wild animal populations, where a human presence is frequently reported, including a constant presence of domestic animals, despite the perceived low risk of emerging resistance to antimicrobials, resistance is likely to develop frequently.

Antimicrobial activity of cell free supernatants from probiotics inhibits against pathogenic bacteria isolated from fresh boar semen

The use of antibiotics with semen extender appears to be a practical solution to minimise bacterial growth in fresh boar semen preservation. Unfortunately, the excessive use of antibiotics promotes antimicrobial resistance (AMR). This becomes a worldwide concern due to the antimicrobial resistance genes transmitted to animals, environment, and humans. Probiotics are one of the alternative methods to reduce antibiotic use. They could inhibit pathogenic bacteria by producing antimicrobial substances in cell free supernatants (CFS). Nevertheless, there is no comprehensive study undertaken on inhibitory activity against pathogenic bacteria isolated from boar semen origin. Our study investigated the efficacy of CFS produced from selected probiotics: Bacillus spp., Enterococcus spp., Weissella spp., Lactobacillus spp., and Pediococcus spp. inhibiting pathogenic bacteria isolated from fresh boar semen. Besides, the semen-origin pathogenic bacteria are subjected to identification, antimicrobial resistance genes detection, and antibiotic susceptibility test (AST). Pseudomonas aeruginosa, Escherichia coli, and Proteus mirabilis are the most common pathogens identified in boar semen with resistance to numerous antibiotics used in pig industry. The CFS with its antimicrobial peptides and/or bacteriocin constituent derived from selected probiotics could inhibit the growth of pathogenic bacteria carrying antimicrobial resistance genes (mcr-3 and int1 genes). The inhibition zones for Pseudomonas aeruginosa, Escherichia coli, and Proteus mirabilis provided more efficient results in the CFS derived from Lactobacillus spp. and Pediococcus spp. than those of the CFS produced from Enterococcus spp., Weissella spp. and Bacillus spp., respectively. It is worth noted that as the incubation time increased, the antibacterial activity decreased conversely. Our results on CFS with its antimicrobial peptides and/or bacteriocin constituent inhibits semen-origin pathogenic bacteria guide the direction as a promising alternative method used in the semen extender preservation of the pig industry.

Detection of antimicrobial producing Staphylococcus from migratory birds: Potential role in nasotracheal microbiota modulation.

A collection of 259 staphylococci of 13 different species [212 coagulase-negative (CoNS) and 47 coagulase-positive (CoPS)] recovered from nasotracheal samples of 87 healthy nestling white storks was tested by the spot-on-lawn method for antimicrobial-activity (AA) against 14 indicator bacteria. Moreover, extracts of AP isolates were obtained [cell-free-supernatants (CFS) both crude and concentrated and butanol extracts] and tested against the 14 indicator bacteria. The microbiota modulation capacity of AP isolates was tested considering: (a) intra-sample AA, against all Gram-positive bacteria recovered in the same stork nasotracheal sample; (b) inter-sample AA against a selection of representative Gram-positive bacteria of the nasotracheal microbiota of all the storks (30 isolates of 29 different species and nine genera). In addition, enzymatic susceptibility test was carried out in selected AP isolates and bacteriocin encoding genes was studied by PCR/sequencing. In this respect, nine isolates (3.5%; seven CoNS and two CoPS) showed AA against at least one indicator bacteria and were considered antimicrobial-producing (AP) isolates. The AP isolates showed AA only for Gram-positive bacteria. Three of these AP isolates (S. hominis X3764, S. sciuri X4000, and S. chromogenes X4620) revealed AA on all extract conditions; other four AP isolates only showed activity in extracts after concentration; the remaining two AP isolates did not show AA in any of extract conditions. As for the microbiota modulation evaluation, three of the nine AP-isolates revealed intra-sample AA. It is to highlight the potent inter-sample AA of the X3764 isolate inhibiting 73% of the 29 representative Gram-positive species of the nasotracheal stork microbiota population. On the other hand, enzymatic analysis carried out in the two highest AP isolates (X3764 and X4000) verified the proteinaceous nature of the antimicrobial compound and PCR analysis revealed the presence of lantibiotic-like encoding genes in the nine AP isolates. In conclusion, these results show that nasotracheal staphylococci of healthy storks, and especially CoNS, produce antimicrobial substances that could be important in the modulations of their nasal microbiota.

EFFECT OF SHELL PASTE ON CARIES INHIBITION

The golden snail is a freshwater mollusk that is an important pest of rice cultivation in Asia. The gold snail shell is almost entirely made of calcium carbonate, which has great potential to assist the manufacture of hydroxyapatite. The content of chitosan in golden snail shells contains an amine group as an antimicrobial substance so that it can inhibit bacterial growth. Calcium carbonate has low solubility in air, which makes it able to neutralize lactic acid and maintain pH at a certain level automatically. Previous research experimentally revealed that the golden snail shell paste (Pomacea canaliculata L.) was able to increase calcium in saliva so that at a concentration of 5% it was able to harden enamel. In this research proposal, the researcher wants to know the effect of shell paste on caries inhibition by looking at the inhibitory power of the paste (streptococcus) and the increase in salivary pH after applying the paste, with the formulation of whether gold snail shell paste is effective in inhibiting the caries process? This research is true experimental research (laboratory) with a post-test control group design, with a total sample of 15 media, divided into 3 treatment groups. It was carried out in the bacteriology laboratory of TLM Poltekkes Palembang. Data analysis used two-way Anova test. The results of this study stated that 5% gold snail shell paste was able to inhibit the caries process by neutralizing salivary pH with calcium carbonate and inhibiting bacteria by chitosan.

Analysis of Antimicrobial Activity of Carrageenan Extracted from Kappaphycus Alvarezii

The abuse of synthetic antibiotics is one of the leading causes of the emergence of antibiotic-resistant microorganisms that have become the primary health concern. To overcome this resistance and counteract all the side effects of synthetic drugs, attention was diverted towards natural resources for developing antimicrobial substances. This study tests the effect of carrageenan isolated from Kappaphycus alvarezii on pathogenic bacteria. Carrageenan is a natural bioactive compound extracted from red algae. Carrageenan was extracted from K. alvarezii using hot water extraction. The antimicrobial property of carrageenan was tested using the Minimum Inhibitory Concentration and the bacterial cell growth rate. Moreover, a commercial antibacterial hand wash and anti-acne toner were used as comparative agents. Firstly, a series of concentrations were used, from 25 µg/mL to 10 mg/mL. The results showed no antimicrobial activity of carrageenan extracted from K. alvarezii using ethanol toward the strains used in this study, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Staphylococcus aureus. However, the carrageenan extracted exhibited a growth-boosting effect over the microorganisms used. Thus, further studies can be carried out using different carrageenan extract methods for K. alvarezii to ensure that anti-microbial compounds from K. alvarezii can be extracted during the carrageenan extraction.

Isolation and characterization of a lipopeptide-producing Bacillus sp. strain JK08 with antagonistic activity against Vibrio parahaemolyticus.

The present study aimed to isolate a potential antagonist Bacillus sp. and evaluate its capacity for controlling pathogenic Vibrio parahaemolyticus in aquaculture. Strain JK08, which showed inhibitory activity against V. parahaemolyticus VP02r, was isolated from a Penaeus vannamei pond. Based on morphological, physiological, and biochemical characteristics and phylogenetic analysis, strain JK08 was identified as Bacillus sp. Through culture condition optimization, the maximal inhibition zone diameter (18.19±0.16 mm) was observed when strain JK08 was cultivated at a temperature of 30°C, pH of 7, and salinity of 20‰ in Luria-Bertani broth for 24 h. The inhibition zone against V. parahaemolyticus VP02r of strain JK08 (∼7 μg, in mass of crude antimicrobial substance, per tablet) was larger than those (14-18 mm in diameter) of several commercial antibiotics (10 μg per tablet) in the in vitro antagonism assay. Liquid chromatography-tandem mass spectrometry analysis results indicated the presence of three families of lipopeptides in the antimicrobial substance: surfactin (C12-C17), iturin A (C14-C17), and fengycin A (C14-C17) and B (C17), which might be the key components contributing to the antagonistic activity of strain JK08. Strain JK08, which is capable of producing antibacterial lipopeptides, shows effective antagonistic activity against V. parahaemolyticus VP02r, implying its promising potential for V. parahaemolyticus control in aquaculture.

Antibacterial Effect of Allium ampeloprasum and Allium porrum Extracts on Staphylococcus aureus and Pseudomonas aeruginosa.

The most prominent microorganisms that cause hospital infections and acquire antibiotic resistance are Staphylococcus aureus and Pseudomonas aeruginosa. The present study aimed to compare the phenolic and flavonoid compounds of various Allium ampeloprasum and Allium porrum extracts and evaluate the antibacterial effects of these extracts against these two microorganisms. The total phenolic and flavonoid contents of the acetone, methanol, aqueous, and hexane leeks extracts from A. ampeloprasum and A. porrum were measured. The antibacterial activity of these extracts against S. aureus and P. aeruginosa was tested using the disk diffusion method for 24, 48, and 72 hours. Further, the minimum inhibitory concentrations and the minimum bactericidal concentrations of these extracts for these two bacteria were evaluated and compared with those of common antibiotics. The aqueous extracts showed the highest phenolic and flavonoid contents and at concentrations of 35 and 40 mg per disk, showed the most antibacterial activity against S. aureus and P. aeruginosa; P. aeruginosa showed more sensitivity to the aqueous extracts than S. aureus. Aqueous A. ampeloprasum and A. porrum extracts may prevent the growth of hospital pathogens, especially P. aeruginosa; our findings will aid the discovery of new antimicrobial substances against antibiotic-resistant bacteria.

Tejsavbaktérium-izolátumok egyes probiotikus tulajdonságainak in vitro vizsgálata

Bacteria carrying genes responsible for antibiotic resistance cannot be used in food production. For this reason,exploring the antibiotic resistance profile of probiotic candidates and the antimicrobial substances theyproduce are essential for probiotic strain selection. The aim of this study was to develop and evaluate additionalelements of a complex in vitro test system for rapid and efficient selection of a large number of putativeprobiotic isolates. In a previous work, we had tested bacterial strains (n=217) isolated from Transylvanian rawsheep milk, cultured sheep milk, and sheep cheese samples and we reduced the sample number to a totalof six Gram-positive, non-hemolytic, catalase-negative, well-aggregating, good acid and bile acid toleratingstrains. In this research, we investigated the antibiotic resistance and antimicrobial production capacity of thepre-selected strains (n=6). The antimicrobial activity of the isolates was determined by the agar well diffusionassay. Strains E15, E66, E173, E198, and E216 were found to inhibit the growth of both Salmonella EnteridisATCC 13076 and the control strain (i.e., Lactobacillus acidophilus ATCC 4356). Antibiotic resistance testswere performed by the agar disk diffusion method. All six isolates belonging to the species of Levilactobacillusbrevis and Lactiplantibacillus plantarum were found to be resistant to several antibiotics and, therefore,cannot be used for the manufacture of commercial probiotic products. In conclusion, our in vitro test systemproved to be capable of effectively screening out unsafe isolates.

Telaah: Pengaruh Variasi Jenis Bahan dan Metode Pengawetan Alami Terhadap Kualitas Telur Ayam

Chicken eggs are one of the food products that are easily contaminated by microorganisms either directly or indirectly. Contamination generally comes from straw where eggs are laid, soil, air and poultry droppings. Eggs stored at room temperature for more than 10-14 days will undergo chemical and microbiological changes which result in a decrease in quality. One of the things that is needed to address this is to preserve egg products so that the products can be stored for a longer time. The main parameters of egg quality can be observed based on the index of egg yolk and egg white, HU value, and pH value. active ingredients contained in the ingredients, conditions and duration of storage, and methods of preservation. Preservation methods can be done by utilizing natural ingredients that contain active compounds. Active compounds that play a role can be tannins, polyphenols, flavonoids which act as natural antimicrobial substances. Generally, these active compounds will inhibit the entry of microorganisms through the pores of the eggs by forming complex compounds so that the metabolism of microorganisms will be disrupted. Keywords: Active Compounds , Damage, Eggs , Natural Ingredients, Preservation .

Antimicrobial activity of moringa leaf infusion on Escherichia coli isolate from Musca domestica L

The Moringa oleifera can be used as a medium for the prevention and treatment of infectious diseases such as diarrhea. Diarrhea can be caused by Escherichia coli, which house flies can transmit. Moringa oleifera leaves have antimicrobial substances such as flavonoids, triterpenoids, steroids, saponins and tannins. This aim of the study was to determine the minimum inhibitory concentration of M. oleifera infusion on the growth of E. coli. This research is a laboratory experiment with Well Diffusion Agar method and dilution technique. The materials used in the study were M. oleifera leaf infusion with concentrations of 50%, 40%, 30%, 20%, and 10%, while 0% was a negative control (Aquadest). E. coli isolates were obtained from M. domestica. The results showed that the inhibition zone formed at concentrations of 50%, 40%, 30%, 20%, 10%, and 0% was 15.55 mm, 13.80 mm, 13.10 mm, 10.10 mm, and 0 mm, respectively. The minimum inhibitory concentration of leaf infusion against E. coli isolates was 25%, and the minimum bactericidal concentration could not be determined because all concentrations tested showed bacterial growth. Instead, the lowest inhibitory concentration was 25%. In concentrations of 50%, 40%, and 30%, M. oleifera leaf infusion has potent antibacterial action; at concentrations of 20%, it has moderate antimicrobial activity; and at concentrations of 10%, it is unable to inhibit the growth of E. coli. Further research is needed to determine the value of the minimum bactericidal concentration at concentrations above 25%, and it is necessary to test it on other digestive tract pathogenic bacteria.

Effects of the cultivation conditions on antimicrobial activity of Lactiplantibacillus sp. NCL33 isolated from Nem chua

There is an increasing demand from consumers for natural and minimally processed foods. Therefore, developing and producing effective natural antimicrobial substances for food preservation is of great interest. This work aimed to investigate the effect of growth conditions on the maximum activity of antibacterial substances production by Lactiplantibacillus sp. NCL33 from Nem chua, a traditional fermented meat. The results revealed that the antibacterial substances exhibited a broad spectrum of antimicrobial activity against Gram-positive and Gram-negative bacteria. The antibacterial activity of NCL33 was optimized with MRS broth supplemented with 20 g/L glucose. The suitable nitrogen source for antibacterial biosynthesis was yeast extract with a concentration of 25 g/L. Moreover, the inoculated temperature and initial pH significantly influenced the antimicrobial activity. The maximum antimicrobial activity of NCL33 was obtained at 30&amp;deg;C and pH 7,0. &amp;nbsp;