Analysis of Native Microflora and Selection of Strains Antagonistic to Human Pathogens on Fresh Produce†

2001 ◽  
Vol 64 (8) ◽  
pp. 1110-1115 ◽  
Author(s):  
CHING-HSING LIAO ◽  
WILLIAM F. FETT
Keyword(s):  
Fresh Produce ◽  
Brain Heart Infusion ◽  
Erwinia Carotovora ◽  
Plate Count ◽  
Human Pathogens ◽  
Green Pepper ◽  
Significant Difference ◽  
Bell Peppers ◽  
Native Microflora ◽  
Baby Carrots

The native microflora of three types of produce (green bell peppers, Romaine lettuce, and prepeeled baby carrots) and two types of sprouting seeds (alfalfa and clover) were investigated. Aerobic plate count (APC) for each produce or seed type as determined on Pseudomonas agar F (PAF) with incubation at 28°C was in the range of 4 to 7 log CFU per g of tissue or seed. There was no significant difference (P ≥ 0.05) in APC when the determinations were made with three agar media including PAF, brain heart infusion agar, and plate count agar. However, the APC as determined from plates that were incubated at 28°C was significantly (P ≤ 0.05) higher than with incubation at 37°C. Fluorescent pseudomonads accounted for 23 to 73% of APC and 6 to 18% of APC recovered from carrots, pepper, and lettuce were pectolytic. Forty-eight strains of pectolytic bacteria were randomly isolated and identified, respectively, as members of the genera of Pseudomonas, Erwinia, Bacillus, Xanthomonas, or Flavobacterium. Lactic acid bacteria and/or yeast were consistently isolated from baby carrots, lettuce, and sprouting seeds (alfalfa or clover) but not from green bell peppers. Approximately 120 strains of indigenous microflora were tested for their ability to inhibit the growth of Salmonella Chester, Listeria monocytogenes, Escherichia coli, or Erwinia carotovora subsp. carotovora on PAF. Six isolates capable of inhibiting the growth of at least one pathogen were isolated and identified, respectively, as Bacillus spp. (three strains), Pseudomonas aeruginosa (one strain), Pseudomonas fluorescens (strain A3), and yeast (strain D1). When green pepper disks were inoculated with strains A3 and D1, the growth of Salmonella Chester and L. monocytogenes on the disks was reduced by 1 and 2 logs, respectively, over a period of 3 days. Application of strains A3 and D1 as potential biopreservatives for enhancing the quality and safety of fresh produce is discussed.

scholarly journals THE EFFECTIVENESS OF SOURSOP LEAF EXTRACT AGAINST GROWTH OF AGGREGATIBACTER ACTINOMYCETEMCOMITANS ATCC® 6514™ IN VITRO

2018 ◽  
Vol 11 (12) ◽  
pp. 411
Author(s):  
Ameta Primasari ◽  
Minasari Nasution ◽  
Nurul Hidayati Arbi ◽  
Dini Permata Sari ◽  
Mohammad Basyuni
Keyword(s):  
Leaf Extract ◽  
Brain Heart Infusion ◽  
Aggregatibacter Actinomycetemcomitans ◽  
Negative Control ◽  
Plate Count ◽  
Control Group ◽  
Control Group Design ◽  
Significant Difference ◽  
Mueller Hinton Agar

Objective: The objective of this study was to determine the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) antibacterial power of soursop leaf extract on Aggregatibacter actinomycetemcomitans (Aa) ATCC® 6514™ growth.Methods: This study was experimental laboratory with post-test only control group design and consists of 8 treatment groups that were soursop leaf extract group with concentration 50%, 25%, 12.5%, 6.25%, 3.125%, and 1.5625% as well as negative control groups were brain heart infusion broth (BHIB) media and chlorhexidine as positive controls. Each treatment was done 3 repetitions. Testing the effectiveness of soursop leaf extract using dilution methods on BHIB and subculture media on Mueller Hinton Agar (MHA) media. The number of Aa ATCC® 6514 ™ colonies was calculated manually using the total plate count method on the MHA media. Data were analyzed using Kruskal–Wallis test (p<0.05) followed by least significance different (LSD) test to see the significant mean difference between treatment groups.Results: Concentration of MIC from soursop leaf extract on Aa ATCC® 6514™ growth was 1.5625% and MBC was 6.25%. LSD assay results showed significant difference effect (p<0.05) Aa ATCC® 6514™ from each treatment group.Conclusion: Soursop leaf extract has antibacterial effectivity against Aa ATCC® 6514 ™.

Growth and Production of Enterotoxins A and D by Staphylococcus aureus in Salad Bar Ingredients and Clam Chowder

1991 ◽  
Vol 54 (11) ◽  
pp. 844-847 ◽  
Author(s):  
HASSAN GOURAMA ◽  
W. Y. J. TSAI ◽  
L. B. BULLERMAN
Keyword(s):  
Staphylococcus Aureus ◽  
Brain Heart Infusion ◽  
Brain Heart Infusion Broth ◽  
Plate Count ◽  
Green Pepper ◽  
Blue Cheese ◽  
Salad Dressing ◽  
Cell Counts ◽  
Elisa Technique ◽  
Number Of Cells

Growth and production of enterotoxins A and D (SEA, SED) by two strains of Staphylococcus aureus were determined in salad bar ingredients and clam chowder. Salad bar ingredients included lettuce, canned black olives, canned green olives, tomato, green pepper, blue cheese salad dressing, blue cheese crumbles, celery, and croutons. Total S. aureus were determined by plate count on Baird-Parker agar. Enterotoxins were quantified by using an ELISA technique. S. aureus did not survive in salad dressing, with pH 4.3. With the exception of olives and blue cheese, S. aureus survived on all ingredients for more than 12 h. After 24 h, the total number of cells decreased on most of the ingredients. S. aureus grew well on green pepper during the first 24 h, reaching 105 CFU/g, but no enterotoxins were detected. S. aureus also increased in moist and dry plain croutons, but there was no detectable production of enterotoxins. S. aureus growth was excellent in clam chowder with cell counts exceeding 108 CFU/g after 12 h at 42°C. Production of SEA and SED began shortly after 3 h. Maximal levels of SEA and SED were 0.29 and 1.6 ng/g, respectively, after 12 h. In brain heart infusion broth, the production of SEA and SED reached 21.9 and 36.3 ng/ml, respectively, after 24 h at 37°C.

Inactivation of Escherichia coli O157:H7 and Salmonella on Mung Beans, Alfalfa, and Other Seed Types Destined for Sprout Production by Using an Oxychloro-Based Sanitizer

2006 ◽  
Vol 69 (7) ◽  
pp. 1571-1578 ◽  
Author(s):  
M. KUMAR ◽  
R. HORA ◽  
M. KOSTRZYNSKA ◽  
W. M. WAITES ◽  
K. WARRINER
Keyword(s):  
Escherichia Coli ◽  
Denaturing Gradient Gel Electrophoresis ◽  
Treatment Time ◽  
Plate Count ◽  
Escherichia Coli O157 ◽  
Human Pathogens ◽  
Treated Seed ◽  
Gradient Gel Electrophoresis ◽  
Aerobic Plate Count ◽  
Native Microflora

The efficacy of a stabilized oxychloro-based food grade sanitizer to decontaminate seeds destined for sprout production has been evaluated. By using mung bean seeds as a model system, it was demonstrated that the sanitizer could be used to inactivate a five-strain cocktail of Escherichia coli O157:H7 or Salmonella introduced onto beans at 103 to 104 CFU/g. Salmonella was more tolerant to stabilized oxychloro than was E. coli O157:H7, with sanitizer levels of &gt;150 and &gt;50 ppm, respectively, being required to ensure pathogen-free sprouts. The decontamination efficacy was also found to be dependent on treatment time (&gt;8 h optimal) and the seed-to-sanitizer ratio (&gt;1:4 optimal). Stabilized oxychloro treatment did not exhibit phytotoxic effects, as germination and sprout yields were not significantly (P &gt; 0.05) different as compared with untreated controls. Although human pathogens could be effectively eliminated from mung beans, the aerobic plate count of native microflora on sprouts grown from treated seed was not significantly (P &gt; 0.05) different from the controls. The diversity of microbial populations (determined through 16S rRNA denaturing gradient gel electrophoresis analysis) associated with bean sprouts was not significantly affected by the sanitizer treatment. However, it was noted that Klebsiella and Herbasprillum (both common plant endophytes) were absent in sprouts derived from decontaminated seed but were present in control sprouts. When a further range of seed types was evaluated, it was found that alfalfa, cress, flax, and soybean could be decontaminated with the stabilized oxychloro sanitizer. However, the decontamination efficacy with other seed types was less consistent. It appears that the rate of seed germination and putative activity of sanitizer sequestering system(s), in addition to other factors, may limit the efficacy of the decontamination method.

Control of Foodborne Pathogens and Soft-Rot Bacteria on Bell Pepper by Three Strains of Bacterial Antagonists†

2009 ◽  
Vol 72 (1) ◽  
pp. 85-92 ◽  
Author(s):  
CHING-HSING LIAO
Keyword(s):  
Foodborne Pathogens ◽  
Erwinia Carotovora ◽  
Soft Rot ◽  
Bell Pepper ◽  
Human Pathogens ◽  
Iron Deficient ◽  
Spoilage Bacteria ◽  
Agar Media ◽  
Inhibition Zones ◽  
Baby Carrots

Forty-two representative strains of native bacteria associated with fresh peeled baby carrots were isolated and characterized. Two of these strains, identified as Pseudomonas fluorescens AG3A (Pf AG3A) and Bacillus YD1, were evaluated in conjunction with another known antagonist, P. fluorescens 2-79 (Pf 2-79), for their potential as biocontrol agents of human pathogens (Listeria monocytogenes, Yersinia enterocolitica, Salmonella enterica, and Escherichia coli O157:H7) and soft-rot bacteria (Erwinia carotovora subsp. carotovora, Pseudomonas marginalis, and Pseudomonas viridiflava). When grown on iron-deficient agar media, all three antagonists produced inhibition zones up to 25 mm in diameter against the growth of human pathogens and soft-rot bacteria. However, when grown on iron-rich agar media, only Pf 2-79 and Bacillus YD1 exhibited antimicrobial activity. Treatment of bell pepper disks with Pf 2-79 or Bacillus YD1 reduced the growth of pathogen by 1.4 to 4.1 log units, depending upon the ratio of the number of antagonist cells to pathogen cells (1:1, 10:1, 100:1, or 1,000:1). The greatest reduction was observed when 10- to 100-fold higher number of antagonists than pathogens was applied. Pf AG3A and Bacillus YD1 reduced the growth of pathogens on pepper disks at 20°C but not at 10°C. However, Pf 2-79 reduced the growth of L. monocytogenes and Y. enterocolitica by up to 4 log units at either 20 or 10°C. Treatment of pepper disks with Pf 2-79 also reduced the incidence of soft rot induced by soft-rot bacteria by 40 to 70%. Pf 2-79 is the most effective of the three antagonists tested for control of spoilage bacteria and human pathogens on bell pepper.

Assessment of Bacterial Contamination of Orthodontic Arch wire

2019 ◽  
Vol 31 (1) ◽  
pp. 48-51
Author(s):  
Suha S Hassan ◽  
Nidhal H. Ghaib ◽  
Batool H Al-Ghurabi
Keyword(s):  
Bacterial Contamination ◽  
Microbial Contamination ◽  
Ethylenediaminetetraacetic Acid ◽  
Bacterial Species ◽  
Brain Heart Infusion ◽  
Control Groups ◽  
Dental Practitioners ◽  
Significant Difference ◽  
Bacillus Spp ◽  
Droplet Transmission

Background: The microorganisms can impend the life of health care professional and particularly the dental practitioners. They can be transmitted by different ways like airborne and droplet transmission. The current study was carried out to identify whether the arch wires that received from the manufactures are free from microbial contamination and to determine the bacterial species attached to the arch wires. Materials and Methods: This study involved eighty samples, consisted of two types of arch wires (nitinol and stainless-steel) from four companies (3M, G&H, Jiscop, OrthoTechnology). These wires inserted in a plane tube that contains 10 -ml of (Tris [tris(hydroxymethyl)aminomethane] and EDTA (ethylenediaminetetraacetic acid) tris-EDTA and brain heart infusion (BHI) broth. A 0.1 ml was withdrawn from the tube and spread on agar plates. The control groups consist of 16 plane tube (8 tubes with tris-EDTA and other 8 tubes with (BHI). Results: Microbial sampling yielded growth from 5 of the 80 arch wires. The predominant bacteria that isolated were Bacillus spp. No growth was recovered from 75 of the samples and from controls. The bacteria were isolated by BHI reagent and no growth was observed by tris-EDTA reagent with statistically significant difference (P<0.05). The Bacillus spp. found only in the G&H and Jiscop companies, however, no statistically significant difference was found among them (P>0.05). With regard to the presence and distribution of bacteria according to the types of wires, the present results clarified that cases of contamination with Bacillus spp. were found in the nitinol arch wires with statistically significant difference (P<0.05). Conclusions: The results of the current study revealed low count of bacterial contamination in the two types of companies (G&H and Jiscop). Not all materials that received from the manufactures are free from contamination and an effective sterilization regimen is needed to avoid cross-contamination.

Picking Regimes Affect Yield, Grade Distribution and Retail Value of Colored Bell Pepper

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 550d-550
Author(s):  
Eric H. Simonne ◽  
John T. Owen
Keyword(s):  
Fruit Size ◽  
Bell Pepper ◽  
Bare Ground ◽  
Green Pepper ◽  
Single Row ◽  
Grade Distribution ◽  
Bell Peppers

The retail value of yellow and red bell peppers is usually three to five times higher than that of the green ones. However, colored bell pepper production in Alabama is presently limited because most growers do not wait the additional 3 to 6 days needed for marketable green pepper to develop color. Hence, drip-irrigated yellow `Admiral' and `Goldcoast' and red `Bell Star' and `Capsitrano' bell peppers were grown in single row and bare-ground, and harvested as needed between July and October 1997 at the 0/3 (green), 1/3 or 2/3 colored stages. The interaction variety × picking method was not signficant (P > 0.50). Early (9,136 kg/ha) and total (32,363 kg/ha) yields of green (0/3) peppers were significantly (P < 0.05) higher than those of the 1/3 and 2/3 colored ones (5,166 and 27,235 kg/ha, respectively). Higher green yields were mainly due to increased numbers of marketable fruits rather than increased fruit size. The longer the pods stayed on the plants, the more likely was sunscald to occur. Retail values (/ha) for the early fancy grade were $10,800 and $20,500 for the green and colored peppers, respectively (using $2 and $6/kg, respectively). These results suggest that the present higher retail value of the colored bell peppers off-sets the lower expected yields.

scholarly journals Biofilm reduction potential of 0.02% polyhexanide irrigation solution in several types of urethral catheters

BMC Urology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Florian H. H. Brill ◽  
Julia Hambach ◽  
Christian Utpatel ◽  
Diana C. Mogrovejo ◽  
Henrik Gabriel ◽  
...  
Keyword(s):  
Membrane Filtration ◽  
Saline Solution ◽  
Bacterial Biofilm ◽  
Plate Count ◽  
Vitro Assay ◽  
Significant Difference ◽  
Irrigation Solution ◽  
Clinically Relevant Bacteria

Abstract Background Long-term use of urethral catheters is associated with high risk of urinary tract infection (UTI) and blockage. Microbial biofilms are a common cause of catheter blockage, reducing their lifetime and significantly increasing morbidity of UTIs. A 0.02% polyhexanide irrigation solution developed for routine mechanical rinsing shows potential for bacterial decolonization of urethral catheters and has the potential to reduce or prevent biofilm formation. Methods Using an in vitro assay with standard market-leading types of catheters artificially contaminated with clinically relevant bacteria, assays were carried out to evaluate the biofilm reduction and prevention potential of a 0.02% polyhexanide solution versus no intervention (standard approach) and irrigation with saline solution (NaCl 0.9%). The efficiency of decolonization was measured through microbial plate count and membrane filtration. Results Irrigation using a 0.02% polyhexanide solution is suitable for the decolonization of a variety of transurethral catheters. The effect observed is significant compared to irrigation with 0.9% saline solution (p = 0.002) or no treatment (p = 0.011). No significant difference was found between irrigation with 0.9% saline solution and no treatment (p = 0.74). Conclusions A 0.02% polyhexanide solution is able to reduce bacterial biofilm from catheters artificially contaminated with clinically relevant bacteria in vitro. The data shows a reduction of the viability of thick bacterial biofilms in a variety of commercially available urinary catheters made from silicone, latex-free silicone, hydrogel-coated silicone and PVC. Further research is required to evaluate the long-term tolerability and efficacy of polyhexanide in clinical practice.

Effect of Sodium Nitrite on Growth of Shigella flexneri

1991 ◽  
Vol 54 (6) ◽  
pp. 424-428 ◽  
Author(s):  
LAURA L. ZAIKA ◽  
ANNA H. KIM ◽  
LOUISE FORD
Keyword(s):  
Exponential Growth ◽  
Shigella Flexneri ◽  
Salt Content ◽  
Brain Heart Infusion ◽  
Growth Curves ◽  
Inhibitory Effect ◽  
Plate Count ◽  
Generation Times ◽  
High Salt Content ◽  
Lag Times

A partial factorial design study of the effect of NaNO2 (0, 100, 200, 1000 ppm) in combination with NaCl (0.5, 2.5, 4.0%), pH (7.5, 6.5, 5.5), and temperature (37, 28, 19°C) on growth of Shigella flexneri is reported. Experiments were done aerobically in brain-heart infusion medium, using an inoculum of 1 × 103 CFU/ml. Growth curves were fitted from plate count data by the Gompertz equation; exponential growth rates, lag times, generation times, and maximum populations were derived for all variable combinations. In the absence of nitrite, the organism grew well under all test conditions at 37 and 28°C but did not grow at 19°C at pH 5.5 nor at pH 7.5 with 4% NaCl. Nitrite did not affect growth in media of pH 7.5 at 37 and 28°C. At pH 6.5 growth was inhibited by 1000 ppm NaNO2. The organism failed to grow at 19°C at all nitrite levels in the presence of 2.5 or 4.0% NaCl. The inhibitory effect of nitrite was much greater in media of pH 5.5 and increased with increasing salt levels. More inhibition was apparent at 28 than at 37°C. While lack of growth was used as a paradigm of the effect of nitrite on S. flexneri, nitrite also increased the lag and generation times and decreased the exponential growth rate. Results indicated that NaNO2 in combinations with low temperature, low pH, and high salt content can effectively inhibit the growth of S. flexneri.

scholarly journals Postharvest Supply Chain with Microbial Travelers: a Farm-to-Retail Microbial Simulation and Visualization Framework

2018 ◽  
Vol 84 (17) ◽  
Author(s):  
Claire Zoellner ◽  
Mohammad Abdullah Al-Mamun ◽  
Yrjo Grohn ◽  
Peter Jackson ◽  
Randy Worobo
Keyword(s):  
Supply Chain ◽  
Foodborne Pathogens ◽  
Empirical Data ◽  
Microbial Growth ◽  
Microbial Contamination ◽  
Fresh Produce ◽  
The United States ◽  
Plate Count ◽  
Modeling Tool ◽  
Parameter Ranges

ABSTRACTFresh produce supply chains present variable and diverse conditions that are relevant to food quality and safety because they may favor microbial growth and survival following contamination. This study presents the development of a simulation and visualization framework to model microbial dynamics on fresh produce moving through postharvest supply chain processes. The postharvest supply chain with microbial travelers (PSCMT) tool provides a modular process modeling approach and graphical user interface to visualize microbial populations and evaluate practices specific to any fresh produce supply chain. The resulting modeling tool was validated with empirical data from an observed tomato supply chain from Mexico to the United States, including the packinghouse, distribution center, and supermarket locations, as an illustrative case study. Due to data limitations, a model-fitting exercise was conducted to demonstrate the calibration of model parameter ranges for microbial indicator populations, i.e., mesophilic aerobic microorganisms (quantified by aerobic plate count and here termed APC) and total coliforms (TC). Exploration and analysis of the parameter space refined appropriate parameter ranges and revealed influential parameters for supermarket indicator microorganism levels on tomatoes. Partial rank correlation coefficient analysis determined that APC levels in supermarkets were most influenced by removal due to spray water washing and microbial growth on the tomato surface at postharvest locations, while TC levels were most influenced by growth on the tomato surface at postharvest locations. Overall, this detailed mechanistic dynamic model of microbial behavior is a unique modeling tool that complements empirical data and visualizes how postharvest supply chain practices influence the fate of microbial contamination on fresh produce.IMPORTANCEPreventing the contamination of fresh produce with foodborne pathogens present in the environment during production and postharvest handling is an important food safety goal. Since studying foodborne pathogens in the environment is a complex and costly endeavor, computer simulation models can help to understand and visualize microorganism behavior resulting from supply chain activities. The postharvest supply chain with microbial travelers (PSCMT) model, presented here, provides a unique tool for postharvest supply chain simulations to evaluate microbial contamination. The tool was validated through modeling an observed tomato supply chain. Visualization of dynamic contamination levels from harvest to the supermarket and analysis of the model parameters highlighted critical points where intervention may prevent microbial levels sufficient to cause foodborne illness. The PSCMT model framework and simulation results support ongoing postharvest research and interventions to improve understanding and control of fresh produce contamination.

scholarly journals Antimicrobial Activity of Red Fruit (Pandanus conoideus Lam) Paste against Staphylococcus aureus and Escherichia coli in Burger Patties

2021 ◽  
Vol 16 (2) ◽  
pp. 132-143
Author(s):  
Selvia Tharukliling ◽  
Lilik Eka Radiati ◽  
Imam Thohari ◽  
Agus Susilo
Keyword(s):  
Fatty Acids ◽  
Staphylococcus Aureus ◽  
Antimicrobial Activity ◽  
Unsaturated Fatty Acids ◽  
Saturated Fatty Acids ◽  
Ethanol Extract ◽  
Plate Count ◽  
Significant Difference ◽  
The Mean ◽  
Paste Content

This study aims to determine the antimicrobial activity of red fruit paste against Staphylococcus aureus FNCC-0047 and Eschericia coli FNCC-0091 by using ethanol and n-hexane as well as the total plate count value of the patty with red fruit paste added on different observations day. The concentration of paste extract for antimicrobial activity test was 6.25%, 12.5%, 25%, 50%. The calculation of the total value of the burger patty plate is calculated on the 3rd, 7th and 14th d with the red fruit paste content in the formula as much as 0%, 5%, 10%, 15%. The results showed that the fatty acids of red fruit paste were dominated by oleic acid and linoleic acid, which are unsaturated fatty acids and palmitic acid, which are saturated fatty acids. The yield of red fruit paste in n-hexane solvent was higher than ethanol solvent. There was a significant difference (P <0.05) from the use of different solvents to the mean clear zone of the two bacteria tested. The antibacterial activity shown by the ethanol extract and n-hexane extract of red fruit paste was in the inactive category at the 6.12% level, the moderate category at the 12.5% to 25% level and the strong category at the 50% level. There was a significant difference (P <0.05) from the total microbial value in each treatment where the higher the red fruit paste content in the patty, the lower the total microbial value found on each d of observation. The use of red fruit paste at a level of 10% to 15% can withstand the rate of microbial growth

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