Effect of Four Presumptive Coliform Test Media, Incubation Time and Product Inoculum Size on Recovery of Coliforms from Dairy Products

1985 ◽  
Vol 48 (5) ◽  
pp. 388-392 ◽  
Author(s):  
B. C. COOKE ◽  
M. A. JORGENSEN ◽  
A. B. MacDONALD
Keyword(s):  
Bile Salt ◽  
Media Studies ◽  
Incubation Time ◽  
Dairy Products ◽  
Limited Range ◽  
Inoculum Size ◽  
Media Type ◽  
Defined Media ◽  
Media Comparison ◽  
Better Than

The need to consider the interrelationship of relevant procedural parameters in media comparison studies has been shown. In this study, the influence of media-type on recovery of coliforms from dairy products was found to be of less importance than the effects of incubation time and inoculum size. Statistically significant media-type effects were found, however, and these contrasted with the observations of other workers in that bile-salt-based media performed better than chemically-defined media. These findings indicate that media studies too specifically designed may yield conclusions with limited range of application.

Research of the activity and viability of spermatozoa at different concentrations and proportions of diluents after incubation

2020 ◽  
pp. 88-95
Author(s):  
Svitlana Lobchenko ◽  
Tetiana Husar ◽  
Viktor Lobchenko
Keyword(s):  
Plasma Concentration ◽  
Incubation Time ◽  
Coefficient Of Variation ◽  
Incubation Medium ◽  
Wide Range ◽  
Series Of Experiments ◽  
The Subject ◽  
Boar Spermatozoa ◽  
Native Plasma ◽  
Better Than

The results of studies of the viability of spermatozoa with different incubation time at different concentrations and using different diluents are highlighted in the article. (Un) concentrated spermatozoa were diluented: 1) with their native plasma; 2) medium 199; 3) a mixture of equal volumes of plasma and medium 199. The experiment was designed to generate experimental samples with spermatozoa concentrations prepared according to the method, namely: 0.2; 0.1; 0.05; 0.025 billion / ml. The sperm was evaluated after 2, 4, 6 and 8 hours. The perspective of such a study is significant and makes it possible to research various aspects of the subject in a wide range. In this regard, a series of experiments were conducted in this area. The data obtained are statistically processed and allow us to highlight the results that relate to each stage of the study. In particular, in this article it was found out some regularities between the viability of sperm, the type of diluent and the rate of rarefaction, as evidenced by the data presented in the tables. As a result of sperm incubation, the viability of spermatozoa remains at least the highest trend when sperm are diluted to a concentration of 0.1 billion / ml, regardless of the type of diluent used. To maintain the viability of sperm using this concentration of medium 199 is not better than its native plasma, and its mixture with an equal volume of plasma through any length of time incubation of such sperm. Most often it is at this concentration of sperm that their viability is characterized by the lowest coefficient of variation, regardless of the type of diluent used, which may indicate the greatest stability of the result under these conditions. The viability of spermatozoa with a concentration of 0.1 billion / ml is statistically significantly reduced only after 6 or even 8 hours of incubation. If the sperm are incubated for only 2 hours, regardless of the type of diluent used, the sperm concentrations tested do not affect the viability of the sperm. Key words: boar, spermatozoa, sperm plasma, concentration, incubation, medium 199, activity, viability, rarefaction.

Assessment of different selective agar media for enumeration and isolation ofListeriafrom dairy products

1988 ◽  
Vol 55 (4) ◽  
pp. 579-583 ◽  
Author(s):  
Lucas Dominguez ◽  
José Francisco Fernández ◽  
Victor Briones ◽  
José Luis Blanco ◽  
Guillermo Suárez
Keyword(s):  
Dairy Products ◽  
Agar Medium ◽  
Raw Milk ◽  
Superior Performance ◽  
Direct Plating ◽  
Selective Agar ◽  
Natural Microflora ◽  
Agar Media ◽  
The Difference ◽  
Better Than

SummaryDifferent selective agar media were compared for the recovery and isolation of five species ofListeriafrom raw milk and cheese. The selective media examined were Beerens medium, MacBride medium and that described by Dominguezet al.(1984) with 6 mg/1 acriflavine, listeria selective agar medium (LSAM), and LSAM with 12 mg/1 acriflavine (LSAM × 2A); a non-selective yeast glucose Lemco agar was included for comparison. When the difference between listeria and the natural microflora of raw milk and cheese was 102cfu/ml, listeria could be isolated by direct plating on all media tested. When it was lower than 103–104cfu/ml, listeria were isolated by direct plating only on LSAM and LSAM × 2A. When the difference was greater than 104cfu/ml, a previous enrichment was necessary to isolate them. LSAM and LSAM × 2A media performed better than the other media tested for isolating listeria by direct plating and improved their isolation from dairy products. This superior performance was evaluated by the ability of these media to support colony formation of different species ofListeriatested, the easy recognition of these colonies from those formed by other microorganisms and by their capacity to inhibit the natural microflora of these foods.

Optimization of dextran production from Leuconostoc strains isolated from different dairy products from Ouargla region Algeria

2022 ◽  
Vol 11 (6) ◽  
pp. 690-699
Author(s):  
M'hamed Bouricha ◽  
Roukia Hammoudi ◽  
Soumia Djelloul Daouadji ◽  
Samia Bissati Bouafia ◽  
Mahfoud Hadj Mahammed ◽  
...  
Keyword(s):  
Yeast Extract ◽  
Dairy Products ◽  
Assay Method ◽  
Total Sugars ◽  
Commercial Use ◽  
Physiological And Biochemical Characteristics ◽  
Good Production ◽  
Sucrose Medium ◽  
Physiological And Biochemical ◽  
Better Than

Leuconostoc (Ln) sp. belongs to a group of lactic acid bacteria, which has the capacity to produce dextran (an exopolysaccharides) in the presence of su-crose. dextran is industrially important, it was the first microbial exopolysac-charide affirmed for commercial use. This study aimed to optimize the pro-duction of the synthesized dextran by Ln strains species isolated from differ-ent dairy products. Morphological, cultural, physiological and biochemical characteristics were employed to identify 23 isolated strains. We have identi-fied the species: Ln. gelidum, Ln. carnosum, Ln. citreum, Ln. fallax, Ln. mesen-teroides subsp mesenteroides, Ln. mesenteroides subsp dextranicum, Ln. mesenteroides subsp cremoris. 20 strains had the capacity to produce dex-tran from sucrose. The precipitation and quantification of EPS on MRSs (Mark rogosa et sharpe sucrose) medium revealed a difference between the strains, by the total sugars assay method, the amount of EPS varied between 0.63 ± 0.19 and 2.41 ± 0.17 g / L of strains LnF70 and LnC1 (isolated from goat's milk), respectively. The dextran production from MRSs medium was better than from liquid MSE. The optimization of production on MRSs medi-um with different concentration of glucose, yeast extract and sucrose showed that the strains had good production with a concentration of 2% glucose, 0.3% yeast extract and 10% sucrose.

scholarly journals Thermoprofile Parameters Affect Survival of Megachile rotundata During Exposure to Low-Temperatures

2019 ◽  
Vol 59 (4) ◽  
pp. 1089-1102 ◽  
Author(s):  
George D Yocum ◽  
Joseph P Rinehart ◽  
Arun Rajamohan ◽  
Julia H Bowsher ◽  
Kathleen M Yeater ◽  
...  
Keyword(s):  
Developmental Stages ◽  
Survival Rates ◽  
Limited Range ◽  
Peak Temperature ◽  
Wave Form ◽  
Base Temperature ◽  
Megachile Rotundata ◽  
Lethal Effects ◽  
Delayed Emergence ◽  
Better Than

Abstract Insects exposed to low temperature stress can experience chill injury, but incorporating fluctuating thermoprofiles increases survival and blocks the development of sub-lethal effects. The specific parameters required for a protective thermoprofile are poorly understood, because most studies test a limited range of thermoprofiles. For example, thermoprofiles with a wave profile may perform better than a square profile, but these two profiles are rarely compared. In this study, two developmental stages of the alfalfa leafcutting bee, Megachile rotundata, eye-pigmented pupae, and emergence-ready adults, were exposed to one of eight thermoprofiles for up to 8 weeks. All the thermoprofiles had a base of 6°C and a peak temperature of either 12°C or 18°C. The duration at peak temperature varied depending on the shape of the thermoprofile, either square or wave form. Two other treatments acted as controls, a constant 6°C and a fluctuating thermal regime (FTR) with a base temperature of 6°C that was interrupted daily by a single, 1-h pulse at 20°C. Compared with constant 6°C, all the test thermoprofiles significantly improved survival. Compared with the FTR control, the thermoprofiles with a peak temperature of 18°C outperformed the 12°C profiles. Bees in the eye-pigmented stage exposed to the 18°C profiles separated into two groups based on the shape of the profile, with higher survival in the square profiles compared with the wave profiles. Bees in the emergence-ready stage exposed to 18°C profiles all had significantly higher survival than bees in the FTR controls. Counter to expectations, the least ecologically relevant thermoprofiles (square) had the highest survival rates and blocked the development of sub-lethal effects (delayed emergence).

Dry Rehydratable Films for Enumeration of Coliforms and Aerobic Bacteria in Dairy Products: Collaborative Study

1989 ◽  
Vol 72 (2) ◽  
pp. 312-318
Author(s):  
Michael S Curiale ◽  
Paul Fahey ◽  
Terrance L Fox ◽  
J Sue Mcallister
Keyword(s):  
Dairy Products ◽  
Collaborative Study ◽  
Ice Cream ◽  
Food Products ◽  
Aerobic Bacteria ◽  
Chocolate Milk ◽  
Coliform Count ◽  
Dry Milk ◽  
Better Than ◽  
Dry Film

Abstract A collaborative study was conducted to compare proposed dry-film plating methods, using aerobic count plates and coliform count plates, to standard agar plating methods for quantifying aerobic bacteria and coliforms in dairy products. In this study, 5 food products (chocolate milk, pasteurized cheese, nonfat dry milk, evaporated milk, and vanilla ice cream), selected as representative dairy products, were analyzed by 11 collaborating laboratories. The results indicate that the dry-film plating methods are equivalent to or better than the agar plating methods. The aerobic count and coliform count dry-film plating methods have been adopted official first action.

Experience with Direct and Indirect UHT Processing of Milk - A Canadian Viewpoint

1982 ◽  
Vol 45 (9) ◽  
pp. 878-883 ◽  
Author(s):  
P. JELEN
Keyword(s):  
Product Quality ◽  
Dairy Products ◽  
Process Engineering ◽  
Consumer Acceptance ◽  
Chocolate Milk ◽  
Engineering Product ◽  
Heating Systems ◽  
Technology Market ◽  
Better Than ◽  
Ancillary Equipment

This brief overview includes some of the Canadian industrial experience gained recently with UHT processing of milk and other dairy products. Emphasis is placed on the differences between direct and indirect heating systems in terms of process engineering, product quality, consumer acceptance, public health aspects and economy. Documented advantages include less fouling, better heat transfer and less heat damage to the final product for direct systems, and less elaborate requirements for ancillary equipment and lower costs for indirect technology. Market performance data from some of the four industrial Canadian producers of 2% and chocolate milk indicate better than expected consumer acceptance due to product quality and other market-related aspects of the UHT process.

scholarly journals Cultivation media for lactic acid bacteria used in dairy products

2019 ◽  
Vol 86 (4) ◽  
pp. 490-502 ◽  
Author(s):  
Saeed A. Hayek ◽  
Rabin Gyawali ◽  
Sulaiman O. Aljaloud ◽  
Albert Krastanov ◽  
Salam A. Ibrahim
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Bacterial Growth ◽  
Dairy Products ◽  
Microbial Control ◽  
Starter Cultures ◽  
Isolation And Identification ◽  
Defined Media ◽  
Growth Requirements ◽  
Large Numbers

AbstractThis review aims to familiarize the reader with research efforts on the cultivation media of lactic acid bacteria (LAB). We have also included a brief discussion on standard ingredients used in LAB media and chemically defined media as related to bacterial growth requirements. Recent research has focused on modifying standard media for the enumeration, differentiation, isolation, and identification of starter cultures and probiotics. Even though large numbers of these media have been developed to serve dairy microbial control, they have failed to provide consistent results. The research consequently points to the need to develop a reliable lactobacilli growth medium for the dairy industry.

scholarly journals Pharmacodynamics of once- or twice-daily levofloxacin versus vancomycin, with or without rifampin, against Staphylococcus aureus in an in vitro model with infected platelet-fibrin clots.

1996 ◽  
Vol 40 (3) ◽  
pp. 701-705 ◽  
Author(s):  
S M Palmer ◽  
M J Rybak
Keyword(s):  
In Vitro Model ◽  
Area Under The Curve ◽  
Human Platelets ◽  
Inoculum Size ◽  
Human Pharmacokinetics ◽  
Development Of Resistance ◽  
Vitro Model ◽  
Better Than ◽  
Fibrin Clots

We compared the pharmacodynamic activities of levofloxacin versus vancomycin, with or without rifampin, in an in vitro model with infected platelet-fibrin clots simulating vegetations. Infected platelet-fibrin clots were prepared with human cryoprecipitate, human platelets, calcium, thrombin, and approximately 10(9) CFU of organisms (MSSA 1199 and MRSA 494) per g and then were suspended via monofilament line into the in vitro model containing Mueller-Hinton growth medium. Antibiotics were administered by bolus injection into the model to simulate human pharmacokinetics; the regimens simulated included levofloxacin at dosages of 800 mg every 24 h (q24h) and 400 mg q12h, vancomycin at 1 g q12h, and rifampin at 600 mg q24h. Each model was run in duplicate over a 72-h period. Infected platelet-fibrin clots were removed in duplicate from each model, weighed, homogenized, serially diluted with sterile 0.9% saline, and plated on tryptic soy agar plates and plates containing antibiotics at 3, 6, and 12 times the MIC to evaluate the emergence of resistance. Time-kill curves were constructed by plotting the inoculum size versus time. Residual inoculum at 72 h was used to compare regimens. All levofloxacin regimens were significantly better than vancomycin monotherapy against both isolates (P < 0.002). Against MSSA 1199, levofloxacin q24h was significantly better than all other regimens, including levofloxacin q12h (P < 0.002); however, no difference between the levofloxacin monotherapy and combination therapy (with rifampin) regimens against MRSA 494 was seen. Killing activity for levofloxacin appeared to correlate better with the peak/MIC ratio than with the area under the curve/MIC ratio. The addition of rifampin significantly enhanced the activity of vancomycin but had little effect upon the activity of levofloxacin. For MRSA 494, vancomycin plus rifampin resulted in the greatest killing (P < 0.05). Development of resistance was not detected with any regimen. Levofloxacin may be a useful therapeutic alternative in the treatment of staphylococcal endocarditis, and further study with animal models of endocarditis or clinical trials are warranted.

Improved method for making high-affinity sections of soft tissue embedded in polyethylene glycol (PEG): its use in screening monoclonal antibodies.

1986 ◽  
Vol 34 (9) ◽  
pp. 1237-1241 ◽  
Author(s):  
J B Bard ◽  
A S Ross
Keyword(s):  
Monoclonal Antibodies ◽  
Polyethylene Glycol ◽  
Limited Range ◽  
Water Soluble ◽  
Frozen Sections ◽  
Polyethylene Glycol 1000 ◽  
Previously Treated ◽  
Mouse Antibody ◽  
Better Than

This article describes improvements in the immunohistologic technique for embedding highly hydrated embryonic tissue in polyethylene glycol 1000 (PEG)--a water-soluble wax of melting point 39 degrees C--and compares the PEG sections with frozen and polyester-wax sections. The main improvement ensures that relatively large PEG sections (8 X 3 mm) stretch out and adhere well to slides: a coat of albumen and glycerine is dried onto the slides and a fresh coat applied just before use. The embedding, sectioning, and mounting procedures, which are considerably faster than those for wax processing, have been developed for screening monoclonal antibodies against the differentiated neural crest cells in the anterior eyes of 9-day-old chick embryos. PEG sections of such eyes were a little fragile, but showed good cellular detail, similar to or better than in wax sections and considerably better than in frozen sections. The responses of PEG sections to the antibodies were far stronger than those of wax and marginally better than those of frozen sections. In one experiment using 125I-labeled rabbit anti-mouse antibody on sections previously treated with antibodies or antisera, PEG sections bound about five times as much label as wax sections and approximately 30% more than frozen sections. The main limitation of the technique is that, because of the softness of PEG, it only works well for embedding a limited range of tissues. Such PEG sections may, however, be useful for in situ hybridization as well as for immunohistochemistry.

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