scholarly journals Effects of water activity on the performance of potassium sorbate and natamycin as preservatives against cheese spoilage moulds

2017 ◽  
Vol 56 (1) ◽  
pp. 85-92 ◽  
Author(s):  
P. Marín ◽  
C. Ginés ◽  
P. Kochaki ◽  
M. Jurado
Keyword(s):  
Sodium Chloride ◽  
Water Activity ◽  
Penicillium Chrysogenum ◽  
Potassium Sorbate ◽  
Mucor Racemosus ◽  
Food Preservatives ◽  
Glycerol Water ◽  
Fungal Inhibition ◽  
Growth Of Fungi ◽  
Different Levels

AbstractThis work investigated the effects of the food preservatives potassium sorbate and natamycin, combined with different levels of ionic (sodium chloride) and non-ioinic (glycerol) water activity (aw), on growth of fungi involved in cheese spoilage. In general, the combined effect of water stress and presence of preservatives enhanced fungal inhibition. However, some doses of potassium sorbate (0.02%) and natamycin (1, 5 and 10 ppm) were able to stimulate growth of Aspergillus varians, Mucor racemosus, Penicillium chrysogenum and P. roqueforti at awvalues in the range of 0.93–0.97. P. solitum was the only species whose growth was consistently reduced by any doses of preservative. The results also showed that sodium chloride and glycerol differentially affected the efficacy of preservatives. This study indicates that awof cheese is a critical parameter to be considered in the formulation of preservative coatings used against fungal spoilage.

scholarly journals Effect of water activity on the growth of fungi isolated from „muesli“ components

2013 ◽  
pp. 31-37
Author(s):  
Gordana Dimic ◽  
Suncica Kocic-Tanackov ◽  
Zeljko Maletic ◽  
Irena Suturovic
Keyword(s):  
Aspergillus Niger ◽  
Water Activity ◽  
Colony Formation ◽  
Penicillium Chrysogenum ◽  
Maximal Growth ◽  
Effect Of Water ◽  
Moisture Conditions ◽  
Growth Of Fungi

The effect of water activity (aw) (0.85-0.97) on the growth of Aspergillus niger, A. flavus, Penicillium chrysogenum, P. brevicompactum and Eurotium herbariorum was examined. The growth of A. niger was lower than that of A. flavus at aw of 0.89 and 0.85. A. niger was the least tolerant of reduced moisture, and low aw (0.85) could prevent colony formation in 5 days. P. brevicompactum was less sensitive to reduced moisture conditions than P. chrysogenum. The maximal growth of E. herbariorum was observed at the level of 0.89 aw. Among the tested fungi, E. herbariorum appeared to be best adapted to the conditions of low aw.

Humectant Permeability Influences Growth and Compatible Solute Uptake by Staphylococcus aureus Subjected to Osmotic Stress

2002 ◽  
Vol 65 (6) ◽  
pp. 1008-1015 ◽  
Author(s):  
ODDUR VILHELMSSON ◽  
KAREN J. MILLER
Keyword(s):  
Staphylococcus Aureus ◽  
Sodium Chloride ◽  
Water Activity ◽  
Glycine Betaine ◽  
Compatible Solutes ◽  
Foodborne Pathogen ◽  
Compatible Solute ◽  
Solute Uptake ◽  
Stressed Cells ◽  
Carnitine Uptake

The effects of different humectants (sodium chloride, sucrose, and glycerol) on the growth of and compatible solute (glycine betaine, proline, and carnitine) uptake by the osmotolerant foodborne pathogen Staphylococcus aureus were investigated. While growth in the presence of the impermeant humectants sodium chloride and sucrose induced the accumulation of proline and glycine betaine by cells, growth in the presence of the permeant humectant glycerol did not. When compatible solutes were omitted from low-water-activity media, growth was very poor in the presence of impermeant humectants. In contrast, the addition of compatible solutes had essentially no effect on growth when cells were grown in low-water-activity media containing glycerol as the humectant. Carnitine was found to accumulate to high intracellular levels in osmotically stressed cells when proline and glycine betaine were absent, making it a potentially important compatible solute for this organism.

Effects of Potassium Sorbate Alone and in Combination with Sodium Chloride on Growth of Staphylococcus aureus MF-31

1987 ◽  
Vol 50 (9) ◽  
pp. 750-752 ◽  
Author(s):  
KATHLEEN A. LAROCCO ◽  
SCOTT E. MARTIN
Keyword(s):  
Staphylococcus Aureus ◽  
Sodium Chloride ◽  
Growth Inhibition ◽  
Cell Population ◽  
Potassium Sorbate ◽  
Growth Studies ◽  
Dual Plating ◽  
Cell Inhibition ◽  
Storage Temperatures

Effects of potassium sorbate alone and in combination with 2 or 3% sodium chloride on growth of Staphylococcus aureus MF-31 were examined. Growth studies were done in tryptic soy broth (final pH, 6.3) at 22°C for 15 d and 35°C for 48 h without shaking. A dual plating procedure was used to monitor growth (tryptic soy agar) and development of injury in the cell population (tryptic soy agar + 7% NaCl). At both storage temperatures, sorbate alone and in combination with 2 or 3% NaCl had only minimal effects on growth inhibition. Presence of NaCl did not appear to enhance effectiveness of sorbate in cell inhibition under these conditions. No injury was observed in the cell population.

Inhibition of Bacterial Histamine Production by Sorbate and other Antimicrobial Agents

1984 ◽  
Vol 47 (7) ◽  
pp. 508-511 ◽  
Author(s):  
STEVE L. TAYLOR ◽  
MARCI W. SPECKHARD
Keyword(s):  
Sodium Chloride ◽  
Klebsiella Pneumoniae ◽  
Bacterial Growth ◽  
Antimicrobial Agents ◽  
Sodium Hexametaphosphate ◽  
Potassium Sorbate ◽  
Sodium Polyphosphate ◽  
Histamine Production

Potassium sorbate at a concentration of 0.5% inhibited growth and histamine production by selected strains of Proteus morganii and Klebsiella pneumoniae in a trypticase-soy broth fortified with histidine (TSBH medium). At 32°C, the inhibition was effective for up to 120 h of incubation; at 10°C, the inhibition was observed through 216 h of incubation. Sodium hexametaphosphate and sodium polyphosphate did not inhibit growth of these histamine-producing bacteria at 32°C, but did slow the rate of histamine production at the 2% level. The extent of reduction of bacterial histamine production by sodium hexametaphosphate and sodium polyphosphate was most pronounced for P. morganii. Sodium chloride at levels up to 2.0% was ineffective in preventing bacterial growth and histamine production.

scholarly journals Cellular and extracellular siderophores of Aspergillus nidulans and Penicillium chrysogenum.

1981 ◽  
Vol 1 (2) ◽  
pp. 94-100 ◽  
Author(s):  
G Charlang ◽  
B Ng ◽  
N H Horowitz ◽  
R M Horowitz
Keyword(s):  
Biological Activity ◽  
Neurospora Crassa ◽  
Aspergillus Nidulans ◽  
Water Activity ◽  
Penicillium Chrysogenum ◽  
Mycelial Growth ◽  
Culture Medium ◽  
Highly Active ◽  
Assay Procedure ◽  
Generally True

Aspergillus nidulans and Penicillium chrysogenum produce specific cellular siderophores in addition to the well-known siderophores of the culture medium. Since this was found previously in Neurospora crassa, it is probably generally true for filamentous ascomycetes. The cellular siderophore of A. nidulans is ferricrocin; that of P. chrysogenum is ferrichrome. A. nidulans also contains triacetylfusigen, a siderophore without apparent biological activity. Conidia of both species lose siderophores at high salt concentrations and become siderophore dependent. This has also been found in N. crassa, where lowering of the water activity has been shown to be the causal factor. We used an assay procedure based on this dependency to reexamine the extracellular siderophores of these species. During rapid mycelial growth, both A. nidulans and P. chrysogenum produced two highly active, unidentified siderophores which were later replaced by a less active or inactive product--coprogen in the case of P. chrysogenum and triacetylfusigen in the case of A. nidulans. N. crassa secreted coprogen only. Fungal siderophore metabolism is varied and complex.

Individual and Combined Effects of Vanillin and Potassium Sorbate on Penicillium digitatum, Penicillium glabrum, and Penicillium italicum Growth

1999 ◽  
Vol 62 (5) ◽  
pp. 541-542 ◽  
Author(s):  
B. MATAMOROS-LEÓN ◽  
A. ARGAIZ ◽  
A. LÓPEZ-MALO
Keyword(s):  
Water Activity ◽  
Inhibitory Concentration ◽  
Synergistic Effects ◽  
Potato Dextrose Agar ◽  
Penicillium Digitatum ◽  
Potassium Sorbate ◽  
Combined Effects ◽  
Fractional Inhibitory Concentration ◽  
Penicillium Italicum ◽  
The Individual

The individual and combined effects of potassium sorbate and vanillin concentrations on the growth of Penicillium digitatum, P. glabrum, and P. italicum in potato dextrose agar adjusted to water activity 0.98 and pH 3.5 were evaluated. Inhibitory concentrations of potassium sorbate varied from 150 ppm for P. digitatum to 700 ppm for P. glabrum, and for vanillin from 1,100 ppm for P. digitatum and P. italicum and 1,300 ppm for P. glabrum. Fractional inhibitory concentration (FIC) isobolograms show curves deviated to the left of the additive line. Calculated FIC index varied from 0.60 to 0.84. FIC index as well as FIC isobolograms show synergistic effects on mold inhibition when vanillin and potassium sorbate are applied in combination.

Antibacterial Effect of Caprylic Acid and Potassium Sorbate in Combination against Listeria monocytogenes ATCC 7644

2020 ◽  
Vol 83 (6) ◽  
pp. 920-927
Author(s):  
KUN HAO ◽  
RIZENG MENG ◽  
XIUJUAN BU ◽  
ZONGHUI LIU ◽  
HAIYANG YAN ◽  
...  
Keyword(s):  
Listeria Monocytogenes ◽  
Caprylic Acid ◽  
Foodborne Pathogen ◽  
Microscopic Analysis ◽  
Antibacterial Activities ◽  
Extracellular Dna ◽  
Potassium Sorbate ◽  
Food Preservatives ◽  
Microdilution Method ◽  
Biofilm Development

ABSTRACT Listeria monocytogenes is a common foodborne pathogen that cause life-threatening infection with high mortality rates. Biofilm development of L. monocytogenes decreases its sensitivity to antibiotics, which has long attracted attention globally. Caprylic acid (CA) and potassium sorbate (PS) are both widely used food preservatives, but their synergistic effect against L. monocytogenes has not been described. This study explored the antibacterial activities of the CA-PS combination against L. monocytogenes ATCC 7644 grown in planktonic or biofilm cultures. The fractional inhibitory concentration index values, determined by the checkerboard microdilution method, were 0.37 ± 0.03 and 0.31 ± 0.04, showing their synergistic antimicrobial effects against L. monocytogenes ATCC 7644 in planktonic and biofilm cultures, respectively. CA-PS effectively eradicated the biofilm biomass to 10.8% by crystal violet assay and to 8.63% by fluorescence microscopic analysis compared with the control. The apoptosis rates of microbial cells embedded within biofilm significantly increased to 51.4%. Subsequent analysis revealed that the combination inhibited biofilm formation by affecting extracellular DNA release and polysaccharide intercellular adhesion expression, which was decreased from 8.93 to 1.04 ng of extracellular DNA per relative biomass and to 54.7% of the control, respectively. In addition, the combination inhibited the growth of L. monocytogenes ATCC 7644 by up to 0.67 ± 0.05 and 0.30 ± 0.03 log CFU/cm2 in planktonic and biofilm modes on a carrot surface, respectively. The synergistic antibacterial effects of CA-PS against L. monocytogenes ATCC 7644 were statistically significant, and the combination is an excellent candidate to be a novel food preservative. HIGHLIGHTS

Effects of potassium sorbate on growth patterns, morphology, and heat resistance of Zygosaccharomyces rouxii at reduced water activity

1992 ◽  
Vol 38 (12) ◽  
pp. 1252-1259 ◽  
Author(s):  
David A. Golden ◽  
Larry R. Beuchat
Keyword(s):  
Heat Resistance ◽  
Water Activity ◽  
Growth Patterns ◽  
Potassium Sorbate ◽  
Heat Sensitivity ◽  
Growth Morphology ◽  
Zygosaccharomyces Rouxii ◽  
Inhibition Of Growth ◽  
Reduced Water ◽  
Sorbate Concentration

A study was made of the effects of potassium sorbate on growth, morphology, and heat sensitivity of an osmotolerant yeast, Zygosaccharomyces rouxii, grown in media (water activity (aw) 0.93) supplemented with glucose and sucrose. Growth patterns of Z. rouxii in YM broth supplemented with glucose (YMBG) and sucrose (YMBS) were similar, although increased potassium sorbate concentration in both media resulted in decreased growth rates. Growth in YMBS containing potassium sorbate was not as prolific as that in YMBG containing potassium sorbate. Inhibition of growth was indicated by decreased absorbance (at 600 nm) of cells grown in YMBS and in YMBG and YMBS supplemented with potassium sorbate at 600 or 1000 μg/mL. Slight decreases in cell size and alteration of cellular morphology were associated with increased potassium sorbate concentration. Plasmolysis increased as potassium sorbate concentration was elevated in YMBS but not in YMBG. Tolerance of Z. rouxii to potassium sorbate was enhanced by previous adaptation of cells in media with elevated potassium sorbate concentrations. Heat resistance of cells unadapted to potassium sorbate showed little or no increase regardless of culture age, but increased substantially in cells grown in media containing potassium sorbate, particularly YMBS. Key words: Zygosaccharomyces rouxii, potassium sorbate, glucose, sucrose, heat resistance.

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