Article

The Effect of Ph on the Efficiency of Various Mold Inhibiting Compounds

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Abstract

Twelve compounds having antifungal activity were investigated at pH levels of 3, 5, 7, and 9 for the effects of pH changes on their relative efficacy against four common mold contaminants. Tests conducted utilized standardized spore suspensions planted on sterile slants of a modified Sabouraud's agar medium containing graded amounts of the antifungal compounds. A majority of the compounds investigated showed a progressive loss of antifungal activity with increasing pH values to the point that some were totally ineffective in the neutral and alkaline range.

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... Sorbic acid and some sorbic acid salts have been widely used for years as preservatives in processed food (Chichester and Tanner, 1972). PS (C 6 H 7 O 2 K; EU E-Number list: E-202) is a wide spectrum antimicrobial food additive with effect against molds and yeasts, mostly within the pH range of 3-6.5 (Bandelin, 1958). PS is more water soluble than sorbic acid, thus it is more appropriate for application as aqueous solutions. ...
... As explained by Eklund (1983), the fungicidal activity of undissociated sorbic acid is 10-600 times more effective than the dissociated form. Thus, the highest efficacy is achieved at the highest concentration of the undissociated form of sorbic acid in the solution, that occur when the pH of the medium where PS is dissolved is as low as 4.77, which is the pK a of PS (Bandelin, 1958). The toxicity of PS aqueous solutions at its natural pH of 7.8 is low, but when applied to citrus fruit they become more active within the wounds in the albedo tissue because of the relatively low pH in these wounds. ...
Article
Several commercially important citrus species and cultivars were artificially inoculated with Penicillium digitatum or Penicillium italicum, immersed 24 h later for 5, 15, 30, or 60 s in water (control) or aqueous solutions of 3% (w/v) potassium sorbate (PS) at 20, 53, 58, 62, 65, or 68 °C, rinsed with tap water, and incubated at 20 °C for 7 d. The most effective treatments were PS applications at 62 °C for 30 or 60 s, which reduced both penicillium molds by up to 20, 25, 50, 80, or 95% on ‘Clemenules’ and ‘Nadorcott’ mandarins, ‘Fino’ lemons, ‘Ortanique’ mandarins, and ‘Valencia’ oranges, respectively. After 60-d storage at 5 °C, green mold and blue mold on ‘Valencia’ oranges treated with PS at 62 °C for 60 s were reduced by 96 and 83%, respectively. Treatments applied to nonwounded fruit before inoculation did not induce disease resistance. In semicommercial trials with ‘Valencia’ oranges, treatments with heated PS alone, PS combined with the fungicide imazalil (IZ), and IZ alone were all equally effective. On ‘Marisol’ clementine mandarins, the combination PS + IZ at room temperature allowed a significant reduction of the IZ doses needed for effective control of green mold.
... The concentrations of (HA)aq,eq were calculated over Equation 1.9 (Henderson-Hasselbalch equation). Sorbate is more effective in foods with low rather than high pH values (Bandelin, 1958;Bell et al., 1959;Lück, 1980;Sofos and Busta, 1981). When observing the results in Table 6 ...
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Food water-in-oil (W│O) emulsions such as margarine, butter and fat spreads are staple foods in households worldwide but are prone to fungal spoilage. The main factors that determine the fungal stability of W│O emulsions are the water content and availability of nutrients, water droplet size distribution (DSD) and the presence of preservatives, such as sorbic acid. The goal of this study was to investigate the role of sorbic acid on the fungal stability of W│O emulsions. First, a theoretical model was developed that describes the distribution of sorbic acid in W│O emulsions, taking into account the pH, mass fraction of lipid phase and solid fat content (SFC). These assumptions were then experimentally validated by HPLC analysis in model W│O systems. The findings were then microbiologically validated in model W│O systems inoculated with Candida guilliermondii where the presence of liquid oil and solid fat influenced the antimicrobial effects of sorbic acid. Afterwards, the influence of emulsification on sorbic acid distribution in W│O emulsions was investigated. Recently, market demand is shifting towards products with less additives. Thus, the effect of droplet size distribution (DSD) and temperature on the fungal stability of W│O emulsions was also investigated. Lastly, the findings regarding sorbic acid behavior in W│O emulsions were validated on industrially produced fat spreads. The applied sorbic acid concentrations were calculated over the proposed sorbic acid distribution model, taking into account the final pH, mass fraction of lipid phase and measured solid fat content (SFC) of the W│O emulsion. The information and real-food validation elucidated in this study might further the efforts of designing microbiologically stable W│O emulsions and reduce the occurrence of fungal spoilage incidents.
... ). This agrees with the observations that at lower pH values, the effectiveness of sorbate increases (2,3). This is evidenced by the fact that at pH 5.5, three to five times as much sorbate was required to get the same antifungal effects as at pH 4.7. ...
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Twostrains ofPenicillium digitatum andone strain ofPenicillium italicum were exposed tovarious levels of sorbic acidandpotassium sorbate, andtheMICswere determined. Selected strains ofthemoldswere then repeatedly exposed tosubinhibitory levels ofthecompounds todetermine whether increased tolerance might develop. TheMICofsorbic acid(pH4.75) toP.digitatum was between 0.02and0.025%. TheMICofsorbate (pH5.5) totwostrains ofP.digitatum andP.italicum was foundtobebetween 0.06and0.08%.Increasing levels ofsorbate resulted inincreasing growth suppression ofthemolds. Populations ofP.digitatum were tested forincreased tolerance tosorbic acid, andnone was found. Individual moldsthat started fromthesame parent colony were examined forincreased tolerance topotassium sorbate. TwoP.digitatum strains developed no observable increased tolerance, butP.italicum developed aslight increase intolerance tosorbate. Whenspores ofP.italicum andP.digitatum were exposed tohigher levels ofsorbate forprolonged times, thefungicidal or fungistatic activity oftheinhibitor was dependent upon pH,length ofexposuretime, level ofsorbate, andthe moldstrain. Moldgrowth on citrus fruits during storage isacontinuing problemthatresults ineconomic loss. Although several fungal species havebeenreported tobeinvolved inthe spoilage ofcitrus products, Penicillium digitatum (green mold)andPenicillium italicum (blue mold) aretheprimary organisms involved. Control ofpostharvest moldspoilage of citrus fruits bytheuse ofbenomylandthiabendazole has beenstandard procedure inmany citrus-producing areas sincetheearly1970s(4,12).However,therehavebeen reportsthatP.digitatum andP.italicum can develop resistance ortolerance tothese fungicides (4,6,8).Harding (4)reported thatbenzimadazole-resistant isolates ofP. digitatum andP.italicum havealsobeenfoundinorchards andcitrus packing-houses inwhichbenzimadazole fungi- cideshadneverbeenused. Inan effort tofind a new fungicide toeffectively combat theseresistant strains, SmootandMcCornack(9)investi- gated theuseofpotassium sorbate forcitrus decaycontrol. Theyreported thata 2% aqueous solution ofpotassium sorbate, applied as a dip,effectively reducedpostharvest decayinseveral citrus products. Although notaseffective as benomyl orthiabendazole, SmootandMcCornack(9)found thatstrains ofP.digitatum resistant tothesefungicides were sensitive topotassium sorbate. Thequestion hasremained, however, whethermoldscommon tocitrus products might alsodevelop resistance tosorbic acidandpotassium sorbate on prolonged usage. Thepurposeofthisinvestigation was todetermine the inhibitory effects ofsorbic acidandpotassium sorbate on P. digitatum andP.italicum andtostudy thepossibility of development oftolerant strains uponrepeated exposureto subinhibitory levels ofthesecompounds.
... Among those films containing organic acid salts, only PS-and SBbased films were effective to control the pathogens, even at neutral pH of the formulations (Table 1). Although these preservatives typically show higher antimicrobial activity at low pH values, several studies confirm that neutral solutions or formulations of these additives have also been effective against Penicillium spp. on citrus fruit (Bandelin, 1958;Palou, Usall, Smilanick, Aguilar, & Viñas, 2002b; Smilanick, Mansour, Gabler, & Sorenson, 2008). Since they are technologically easier to prepare, they were used in this study. ...
Article
The performance of edible composite coatings containing hydroxypropyl methylcellulose (HPMC), hydrophobic components (beeswax and shellac), and food preservatives as antifungal ingredients was evaluated on ‘Clemenules’ clementine mandarins. Tested preservatives included potassium sorbate (PS), sodium benzoate (SB), sodium propionate (SP), and their mixtures. Intact fruit or fruit artificially inoculated with Penicillium digitatum or Penicillium italicum, the causal agents of citrus postharvest green (GM) and blue (BM) molds, respectively, were coated and stored up to 30 d at 5 °C plus 7 d at 20 °C of shelf-life. During cold storage, all HPMC-lipid coatings containing food additives significantly reduced the development of both GM and BM, although the performance was better against GM. When coated fruit were transferred to 20 °C, all coatings lost effectiveness. SB + PS-based coating was the most effective to reduce disease severity. All the coatings effectively reduced weight loss and maintained rind firmness of coated ‘Clemenules’ mandarins. The coatings did not adversely affect the ethanol content of the juice, sensory flavor, and fruit appearance. Although the internal gas concentration of coated fruit was modified, the coatings did not induce off-flavor.
... wn inFig. (1). There was an inverse relationship between the concentration of NaHCO 3 in the media and the degree of fungal growth however, Aspergillus flavus was more sensitive for the medium pH than the other two fungi strains. The fungal growth was markedly suppressed by increasing the concentration of NaHCO 3 to 5% in the cultivated PDA medium. Bandelin (1958) stated a progressive loss of antifungal activity of spore suspensions planted on sterile slants of a modified Sabouraud's agar medium with increasing pH values to the point that some were totally ineffective in the neutral and alkaline range. Also, Wheeler, et al., (1990) found that Aspergillus species were more tolerant of alkaline pH ...
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The growth of fungi on cheese surface causes significant economic losses for producers in addition to the negative impact on the consumers health as a result of their exposure to mycotoxins, especially that produced by Aspergillus spp. The present study is a trail to protect Ras cheese from fungal attack. The cheese wheels was coated with a water suspension of 50% of bentonite clay, sprayed with 5% of sodium bicarbonate (NaHCO3) solution or wrapped with plastic membranes treated with 5% solution of NaHCO3 and compared with control cheese wheels (without treatment) during 6 months of ripening and cold storage. The results showed in vitro growth inhibition effect of of Aspergillus flavus, Aspergillus niger and Penicillium requeforti cultivated in PDA medium amended with bentonite clay (50%) or NaHCO3 (5%) solutions. These two treatments were found to prevent fungal growth on cheese surface without affecting the chemical and the sensory properties of cheese.
... A report in the literature shows that the relative efficacies of the antifungal activities of the compounds could be affected by the changes of the pH of the medium containing antifungal compounds. It has been also observed from the literature that with increasing pH values, there was a progressive loss of antifungal activity of the compounds; even in some cases, the few compounds were completely ineffective in the alkaline and neutral pH [38]. With this knowledge of the above literature precedents, a sincere attempt is made to investigate the effect of different solvent on the pH of the SeNPs; the investigation data could be useful at the time of formulation and dose fixation study. ...
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Selenium nanoparticles (SeNPs) were synthesized through the bioreduction of sodium selenite (Na2SeO3) using gram-negative agrobacterium (AGBT) species. Subsequently, their physicochemical properties (pH, viscosity and surface tension) and medicinal activities as anti-dermatophyte against soil keratinophilic fungi at the molecular level were assessed. UV–visible and FTIR spectroscopic data of the biologically synthesized SeNPs were then recorded for confirming the presence of native biological materials adhered to nanoparticles, which are inherently required to enhance the stability and solubility through inhibition of the nanoparticle's natural aggregation and agglomeration. The λ max value between 290–300 nm in the absorption spectra of the biogenic materials in different concentrations of the Na2SeO3 corroborated the presence of SeNPs in the solution. The interaction of SeNPs in solution state was further studied through the determination of pH, viscosity and surface tension values of agrobacterium-derived SeNPs in different solvents. The pH value of SeNPs dispersed in water is reported as above 7.0 and the average viscosity, and surface tensions of the SeNPs are appeared as near to the water. The particle size distribution was further determined by DLS and the highest % of particle size of the synthesized SeNPs is found in between 200–300 nm. The anti-dermatophyte activity and molecular interaction with fungi DNA molecules were assessed providing the highest anti-dermatophyte activity at 0.1 M concentration and it is observed that the quantities and qualities of fungi DNA were affected by SeNPs. Considering all the outcomes of the studies together, our findings suggest that agrobacterium-mediated synthesis of SeNPs is dependent on bacterial metabolisms but not on the concentration of Na2SeO3 and are promising selenium-derived species with potential application in the prevention of fungal infection through denaturation of fungi DNA.
... Indeed, in Wolf 's 1950 paper [97], the MIC against S. aureus remained at 0.3% from pH 5 to 9. However, loss of activity at alkaline pH values was noted by Bandelin [98] in his detailed study of the effect of pH on the activity of antifungal compounds, as would be predicted by the pK a value. Little was known about its mode of action, although Seevers et al. [99] produced evidence that DHA inhibited succinoxidase activity in mammalian tissue, while Wolf and Westveer [100] showed that it did not react with microbial -SH enzymes. ...
... The MIC in this study of potassium sorbate against test molds ranged between 750 to 1500 ppm at pH 6.0 and 500 -1500 ppm, at pH 5.0 and 5.5. The results indicated that the MIC of potassium sorbate at pH 5.0 was slightly contrary to the observations of [20], who reported that the minimum antimicrobial activity of sorbate was 800 ppm at pH 5.0. However, [21] observed that the MIC of potassium sorbate was in the range between 100 -1000 ppm and was dependent on the pH of the substrate, types and numbers of molds, as well as their environmental factors. ...
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Inhibition of spoilage mold of common contaminant of bakery goods in modal agar system by potassium sorbate and calcium propionate in wide range of concentration (0 -2000 ppm) at different pH (5.5 -7) was investigated. All Sam-ples were examined daily for mold growth. Results showed that both potassium sorbate and calcium propionate can be used effectively to inhibit mold growth and the effectiveness of these preservatives is enhanced by increasing the con-centration and decreasing the pH. The effect of modified atmosphere packaging (MAP) comprised of 60% or 80% CO 2 (balance N 2) and oxygen absorbents on the growth of mold was also studied on the agar system. The results indicated that mold growth was prevented up to 42 days in packs flushed with 60% or 80% CO 2 (balance N 2). It was also evident that all samples did not show mold growth for >40 days when packaged in the presence of oxygen scavenger sachet.
... Conversely, commonly used organic acids exhibiting antimicrobial activities, such as benzoic, salicylic, and propionic acid lost their activity at higher pH due to deprotonation of their functional groups, causing them to be negatively charged. The electrostatic repulsion between the negatively charged cells and the compounds prevented penetration (6). The influence of environmental conditions can generally be seen when studying the pH and salt dependence of the activities of antimicrobials (2,17). ...
Article
Antimicrobial activity and mechanism of action of rosmarinic acid (RA) and dodecyl rosmarinate (RE12) against Staphylococcus carnosus LTH1502 were studied as a function of pH (5.8 to 7.2) and in the presence of salts (KCl and MgCl2, 0 to 500 mM). Microbial cultures were exposed to unesterified RA and to esterified RE12, and cell number was determined by plate counting. Cells exposed to RA and RE12 at the minimum bactericidal concentration (200 and 0.05 mM, respectively) were examined using scanning electron microscopy to observe potential morphological changes. Activity of RA was found to be strongly dependent on pH, salt type, and concentration, whereas RE12 led to the compound's activity becoming independent of pH, salt concentration, and type. Scanning electron microscopy images showed that morphology of cells treated with RE12 after incubation of 1 h was irrevocably altered. Our results suggest that esterification (i) altered the mechanism of action by increasing the compound's affinity for cell membranes and (ii) decreased the compound's susceptibility to changes in environmental conditions that alter its charge. Highly specific changes in structure-activity relationships can be observed when esterifying a naturally active phenol such as RA with an alkyl chain that has a carbon chain length of 12.
Article
The toxicity of propionic acid to cultures of two isolates each of Fusarium culmorum, Aspergillus candidus and Paecilomyces varioti and one isolate of Cladosporium cladosporioides was determined by four methods, involving measurement of spore germination, of radial growth on agar, of growth in shake cultures and of size of inhibition zones produced by paper disks. All the fungi were inhibited by 100 000 ppm acid in paper disks but not by 10 000 ppm, although 10 000 ppm caused complete inhibition of growth or germination in the other three methods. With both isolates of F. culmorum and the isolate of C. cladosporioides 1 000 ppm were completely inhibitory to germination and to radial and shake growth; with the A. candidus isolates there was limited radial growth at an initial concentration of 1 000 ppm acid, but complete inhibition of germination and shake growth. The two isolates of P. varioti grew nearly as well in 1000 ppm acid as the controls and the spores also germinated well. There was evidence of inhibition of shake growth of some of the fungi with 100 ppm acid, but 10 and 1 ppm did not cause inhibition whichever technique of measurement was used.
Article
Paecilomyces variotii and members of the Aspergillus glaucus group, principally A. repens, were isolated from propionic-acid-treated hay. On agar media, both P. varioti and A. glaucus group species grew in the presence of up to 135 mM propionate; half the A. glaucus isolates grew on 108 mm, 70% on 54 mm and all on 27 mm propionate. In liquid media only a few isolates of A. chevalieri and A. ruber tolerated 80 mm propionate. Repeated culturing of A. glaucus group species on propionate-containing media did not increase tolerance. The onset of growth was delayed by propionate in the medium, the delay increasing with increasing concentration. Growth was always accompanied by metabolism of propionic acid. A. glaucus was most sensitive to propionate at pH 4, but the sensitivity of P. variotii varied little between pH 4 and 7. Other aliphatic acids stopped growth of both P. variotii and A. glaucus, the concentrations needed diminishing as chain length increased up to C9 or C10. Antifungal activity then decreased with increased chain length so that saturated solutions of dodecanoic acid (C12) failed to stop growth. Growing fungi degraded the acids.
Chapter
Citrus are nonclimacteric fruits that are harvested when their commercial maturity index has already been reached. The maturity index expresses the relationship between two important internal quality parameters, solid soluble concentration and titratable acidity, that determine the fruit consumer acceptance. These values are not dependent on postharvest external quality attributes and, for instance, fully-ripened fruit may still have green-colored rind. For this reason early mandarins or lemons may be artificially degreened through treatments with exogenous ethylene. Postharvest handling in citrus packinghouses, including degreening, packingline procedures, cold storage, or other treatments, are intended to commercialize fruit of maximum quality, increase their postharvest life, and reduce produce losses. According to their origin, major postharvest losses are caused by weight loss, physiological disorders, biotic diseases, and quarantine pests. Conventional synthetic waxes, often amended with chemical fungicides, other specific treatments with conventional synthetic fungicides, or in-transit cold treatments against quarantine fruit flies have been used for many years by the export citrus industry to minimize postharvest losses. However, the repeated use of these practices has arisen important problems that increasingly limit the profitable commercialization of fresh citrus fruits. These problems include, for example, health and environmental issues associated with conventional waxes containing ammoniacal compounds or synthetic fungicides like imazalil, thiabendazole or sodium ortho-phenyl phenate that generate chemical residues and lead to the proliferation of pathogenic resistant strains. Furthermore, lengthy standard cold treatments are not appropriate for mandarin cultivars susceptible to chilling injury. There is, therefore, an increasing need to find and implement alternatives to these traditional postharvest procedures. In this chapter, novel approaches for postharvest preservation of fresh citrus fruits are reviewed. Substantial progress has been accomplished in evaluating new effective postharvest disease control methods as part of integrated disease management programs. New active ingredients such as pyrimethanil, fludioxonil, azoxystrobin or trifloxystrobin, classified as reduced risk fungicides; low-toxicity or natural antifungal chemicals such as food additives, generally regarded as safe compounds, or essential oils have been tested alone or in combinations against the most important citrus postharvest diseases worldwide, namely green and blue molds and sour rot, caused by Penicillium digitatum, Penicillium italicum and Geotrichum citri-aurantii, respectively. The development of composite natural edible coatings to substitute conventional citrus waxes or, in the case of incorporating low-toxicity antifungal ingredients, to replace also the use of synthetic fungicides, is currently an active research field. Likewise, attention has been devoted to the evaluation of methods alternative to the mandatory cold exposure for the control of important citrus quarantine pests such as the Mediterranean fruit fly Ceratitis caPItata. Such alternatives include heat, insecticidal controlled atmospheres, ionizing radiation (γ-, β-, X-rays) and combinations of these treatments.
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Oxygen uptake by lipolytic fungi on arachis oil is in the order Aspergillus flavus (brown) > A. niger > Rhizopus arrhizus > Rh. cohnii > A. flavus (green). Respiration is stimulated by low concentrations of benzoic acid, hydroxybenzoates and phenol, but with higher concentrations it is inhibited. Concentrations which give relatively low oxygen uptake are also fungistatic. The factors governing partitioning in oil-water systems are used to calculate the inhibitory concentration of benzoic acid in the aqueous phase.
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The antimicrobial activity of the soluble potassium salts of methyl, ethyl, propyl, and butyl parabens were evaluated to determine whether they would be more effective than their respective parabens (esters ofp-hydroxybenzoic acids). The potassium salts of the methyl and ethyl parabens as well as methyl and ethyl parabens were microbiocidal against the fungusAspergillus niger and five bacteria, whereas the potassium salts of propyl and butyl parabens and their respective parabens were not microbiocidal against all the test organisms. In the presence of several ingredients frequently used in pharmaceutical and cosmetic formulations, ethylenediaminetetraacetate (EDTA) and magnesium hydroxide did not interfere with the antimicrobial activity of the potassium salts of parabens and appeared to be microbiocidal against three of four test organisms. Simethicone and Tween 80 interfered with the antimicrobial activity of the preservatives. At pH 4–6, the potassium salt of butyl paraben, the only preservative tested, was active against more organisms than at pH 7–8. Overall, the highly soluble potassium salts of parabens showed microbiocidal activity against more of the test organisms than the less soluble parabens.
Chapter
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This chapter begins with a definition of the Target Product Profile which defines the goal for the drug product and guides formulation research and development activities. Formulation research begins with the generation of the preformulation information (physicochemical properties) and leads to the selection of a prototype suspension formulation. This chapter also outlines the formulation optimization and development activities required to iteractively refine the formulation composition and process as the project proceeds to the point of filing an NDA.
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The concentrations of formic, acetic, propionic and butyric acids required to prevent growth of Fusarium in wheat grain cultures were determined. The cultures were maintained at 31% moisture content and stored for 4 weeks at 25 ºC followed by 6 weeks at 12 ºC, which were optimum conditions for growth of Fusarium and synthesis of the mycotoxin, zearalenone. Under these conditions the critical concentration of all the acids, whether used singly or in combination, was between 1000 and 10 000 parts/million (equivalent to 0.1% and 1% w/w). At 1000 parts/million and below the fungus was able to develop and zearalenone synthesis was not affected except where acetic acid was used alone, when higher toxin yields were recorded.
Article
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Two strains of Penicillium digitatum and one strain of Penicillium italicum were exposed to various levels of sorbic acid and potassium sorbate, and the MICs were determined. Selected strains of the molds were then repeatedly exposed to subinhibitory levels of the compounds to determine whether increased tolerance might develop. The MIC of sorbic acid (pH 4.75) to P. digitatum was between 0.02 and 0.025%. The MIC of sorbate (pH 5.5) to two strains of P. digitatum and P. italicum was found to be between 0.06 and 0.08%. Increasing levels of sorbate resulted in increasing growth suppression of the molds. Populations of P. digitatum were tested for increased tolerance to sorbic acid, and none was found. Individual molds that started from the same parent colony were examined for increased tolerance to potassium sorbate. Two P. digitatum strains developed no observable increased tolerance, but P. italicum developed a slight increase in tolerance to sorbate. When spores of P. italicum and P. digitatum were exposed to higher levels of sorbate for prolonged times, the fungicidal or fungistatic activity of the inhibitor was dependent upon pH, length of exposure time, level of sorbate, and the mold strain.
This reviewer finds it difficult to recommend this book to American colleagues. This statement is not meant so much to be critical of the content, format, or quality of illustrations as it is to stress the fact that we have several outstanding American textbooks which have been carefully edited by distinguished co-editors or authors. In an effort to find differences in emphasis or coverage, the reviewer read in detail those sections which the author referred to as using a "global" approach to pediatrics as a substitute for a chapter on tropical pediatrics. The result was disappointing, particularly since the author spent considerable time in a developing country. While many of the diseases of the tropics are the same as those in temperate climates, the author knows the experience of his own Colonial Health Service when his students went to India, to Singapore, or to the Gold Coast of Africa. Many
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Free p-hydroxybenzoic acid and its metabolic products in which the phenolic group has not been destroyed have been determined in tissues and biological fluids of drugs, tablets, and man following the ingestion of the acid and its esters. Recoveries from the urine of animals, regardless of the method of administration, range between 50 and 95 per cent except in the case of butyl esters where the recoveries were approximately 40 per cent. High plasma levels and urinary output of free and conjugated p-hydroxybenzoic acid in dogs indicate that hydrolysis of the ester linkage and metabolic conjugation constitute the chief paths of alteration for all of the esters studied except the butyl derivative. Topical application of ointments containing 10 per cent methyl and 10 per cent propyl p-hydroxybenzoate to the shaved backs of white rabbits produced no irritation during forty-eight hours of contact. Under this condition no drug concentration was detected in the kidneys.
Article
THE USE of the fatty acids in the treatment of mycotic infections was introduced by Peck and his associates.¹ They were led to this treatment because their investigations had convinced them that human perspiration played a role as a protective mantle against infections generally and fungous infections in particular. The basis for their treatment was founded on the fact that they were able to demonstrate that sweat was fungicidal and fungistatic, because of its content of fatty acids. Previous investigations on the fatty acid series from C1 to C11 by Peck and Rosenfeld² had demonstrated that the fatty acids inhibited growth of pathogenic fungi and that in proper concentration many of them were fungicidal. Since then many investigators have confirmed the therapeutic value of fatty acids in mycotic diseases. It is important to emphasize that the use of fatty acids is an advance in treatment, not
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The history of the esters of p-hydroxybenzoic acid and their uses as preservatives in pharmaceuticals, cosmetics, foods, and industrial products are discussed. Antimicrobial studies show that the methyl, ethyl, propyl, and butyl esters are effective in low concentrations against fungi and Gram-positive bacteria, but less effective against Gram-negative bacteria. The esters are more fungistatic than fungicidal. The p-hydroxybenzoates were also tested against microorganisms in the presence of humans serum, and against the growth of A. niger in procaine nicillin suspensions. The physical and chemical proprties of the p-hydroxygnwates are extensively described, as well as methods of incorporation and a method of determination by ultraviolet absorption.
Article
A comparison of the fungistatic property of sorbic acid and benzoic acid was undertaken to determine their efficacy against common mold contaminants and as a preservative in certain pharmaceutical preparations that are susceptible to mold growth. Sorbic acid was found to be superior to benzoic acid as a fungistatic agent.
Article
Some of the physical and pharmacologic properties of ethyl vanillate, a new fungistatic or fungicidal agent, have been briefly stated. The records of 12 patients with progressive disseminated histoplasmosis treated with ethyl vanillate have been reviewed. Five of these patients are alive and apparently well following treatment, an experience not previously encountered or reported in the literature. The use of the drug in the treatment of histoplasmosis has been outlined and the toxic manifestations of overdosage have been described.
Disinfection and Sterilization
  • E C Mcculloch
McCulloch, E. C., " Disinfection and Sterilization, "
Bacteriology and Allied Subjects Antiseotics. Disinfectants. Funri-2nd ed cide's and Sterilization
  • L Gershenfeld
Gershenfeld, L., " Bacteriology and Allied Subjects, " (3) Reddish. G. F.. " Antiseotics. Disinfectants. Funri-2nd ed.. Lea and Febiger, Philadelphia, 1945. Mack Printing Co., Easton, Pa., 1945. cide's and Sterilization, " Lea andkebi'ger, Philadelphia, lQg4. (1945).
Intern. Congr. Pure and Appl. Chem.(appendix)
  • Yabuta
A. M. A. Arch. Dermatol
  • Mitchell
Arch. Dermatol. u. Syphilis
  • Peck
Mich. State Univ. Agr. Exp. Sta. Mem. Quart. Bull
  • Brunner