Growth Of Rhizopus Stolonifer Research Articles

Biodegradable soy protein isolate carvacrol coating controls soft rot on nectarines by enhancing defense response

Nectarine fruits are rich in nutrients, which are susceptible to fungal infection during postharvest, resulting in quality deterioration and decay. This study aimed to assess the effect of different concentrations of carvacrol and soy protein isolate coatings on the fungal infection and quality characteristics of nectarines during postharvest storage. The results showed that soy protein isolate carvacrol (SPI-C) coating inhibited the growth of Rhizopus stolonifer in vitro. The SPI-C coating significantly reduced the incidence of postharvest soft rot, maintained the postharvest quality of nectarines during storage. SPI-C coating induces the defense response to soft rot by enhancing the accumulation of phenolic, flavonoids and lignin, and up-regulating the expression of defense-related genes in nectarines. The SPI-C coating activated the transcription of antioxidant enzymes (CAT, SOD and POD) and eliminated ROS damage. The disease resistance response promotes the production of defense-related substances by upregulating the gene expression of PpPPO and PpPAL. In summary, SPI-C coating significantly reduces the incidence of postharvest soft rot, maintains the postharvest quality and induces defense response to soft rot by enhancing the expression of genes involved in phenylpropanoid metabolism in nectarines during storage.

Electrically conductive bioplastics based on chitosan, polyvinyl alcohol, polyvinyl pyrrolidone, and plant extract nanoparticles for detecting Rhizopus stolonifer on tomato fruit

AbstractThis work aimed to manufacture bioplastics with mechanical and electrical properties for monitoring the Rhizopus stolonifer growth in tomato fruit packaging. Bioplastics were based on chitosan/polyvinyl alcohol (Ch/PVA), chitosan/polyvinyl pyrrolidone (Ch/PVP), and nanoparticles (NPs) of plant extracts at 10% and 30% of concentrations. Bioplastics were exposed to tomato inoculated with R. stolonifer for 6 d at 25°C. Water vapor permeability (WVP), mechanical properties, FTIR, UV–vis, morphology, electrical resistance of bioplastics, and the NPs size were assessed. In bioplastics added with plant extracts, 1.5 times more WVP than in the control group (18–35 gs−1m−1Pa−1) were quantified. Ch/PVA bioplastic showed 51% more tensile strength, 44% more elongation at break, and 40% more Young's modulus than Ch/PVP, regardless of the plant extract. The electrical resistance in Ch/PVA bioplastics with 30% mushroom extract and 10% radish allowed the differentiation between inoculated (109–1010 Ω) and non‐inoculated tomatoes (1010–1011 Ω). The FTIR assay confirmed the presence of each compound used in the bioplastic, and UV–vis confirmed phenols at 300 nm. The NPs measured less than 50 nm. Only Ch/PVA with 30% mushroom and 10% radish can be useful to monitor fungi in tomatoes based on their electrical behavior.

Inhibitory Effect of Natural Honey on The Growth of Rhizopus stolonifer, Mucor spp., and Aspergillus niger

Background: Honey is frequently used as an antiseptic, prophylactic, and therapeutic agent for many infections. The chemical and physical properties of honey have an inhibitory effect on a lot of microorganisms including fungi. Rhizopus stolonifer, Mucor spp., and Aspergillus niger are common indoor molds that contaminate bread and eatable plants. During growth on bread, they multiply and produce large numbers of spores that can cause different types of infections, especially in immunocompromised patients. Objectives: 1) To evaluate the effect of natural honey on the growth of Rhizopus stolonifer, Mucor spp., and Aspergillus niger fungi. 2) To determine the minimal inhibitory concentration of honey that can suppress the growth of these fungi. 3) To assess the possibility of using honey as a natural replacement for chemical preservatives. Methodology: This experimental study was conducted in the College of Sciences at King Saud University between August and November 2021 in Riyadh, KSA. Multifloral honey was diluted in sterile distilled water volume to volume (%, v/v) in series concentrations: 5%, 15%, 30%, 45%, and 60%. The diluted samples of honey were then added to potato dextrose agar (PDA). Measured parts of the colonies of Rhizopus stolonifer, Mucor, and Aspergillus niger, were cultured on the PDA plates with the diluted honey. Two replicates were used for every concentration of each fungus. The inoculated plates, including the controls, were incubated at room temperature (25±2°C). Fungal growth was monitored daily for three months. Results: The 5%, 15%, and 35% concentrations of honey mixed with PDA did not inhibit the fungal growth, the fungi grew within the first 24h while the 60 % dilute concentration killed the three fungi and completely inhibited their growth. The fungi were monitored for 3 months; during that time, there was no growth. In conclusion: This study confirms that honey strongly inhibits the growth of Rhizopus Stolonifer, Mucor spp., and Aspergillus niger when used in a concentration of 60% or above. Accordingly based on these findings we determine that the minimal inhibitory concentration (MIC) of multi-floral honey on bread fungi is 60%.

Analyzing honey’s ability to inhibit the growth of Rhizopus stolonifer

Rhizopus stolonifer is a mold commonly found growing on bread that can cause many negative health effects when consumed. Preservatives are the well-known answer to this problem; however, many preservatives are not naturally found in food, and some have negative health effects of their own. We focused on honey as a possible solution because of its natural origin and self-preservation ability. We hypothesized that honey would decrease the growth rate of R. stolonifer . We evaluated the honey with a zone of inhibition (ZOI) test on agar plates. Sabouraud dextrose agar was mixed with differing volumes of honey to generate concentrations between 10.0% and 30.0%. These plates were then inoculated with a solution of spores collected from the mold. The ZOI was measured to determine antifungal effectiveness. A statistically significant difference was found between the means of all concentrations except for 20.0% and 22.5%. Our findings support the hypothesis as we showed a positive correlation between the honey concentration and growth rate of mold. By using this data, progress could be made on an all-natural, honey-based preservative.

Development of gelatin/carboxymethylcellulose active films containing Hass avocado peel extract and their application as a packaging for the preservation of berries

This study aimed to evaluate the effect of incorporating different concentrations (0, 200, 300, and 400 mg L−1) of avocado peel extracts (EE-AP) on the physicochemical properties and antifungal activity of gelatin-carboxymethylcellulose (Gel-CMC) films and their applicability in berry preservation. The results showed that incorporating EE-AP was compatible with the Gel-CMC film and enhanced the mechanical properties without affecting the integrity and thermal properties. The 200 mg L−1 of EE-AP concentration on films offered the best barrier properties against water vapor (2.90 × 10−11 g m−1 s−1 Pa−1). FTIR identified the intramolecular and intermolecular interactions between the functional groups of biopolymers and the EE-AP. The results obtained revealed that EE-AP incorporation into gelatin-carboxymethylcellulose films significantly decreased the moisture content (from 12.48 to 11.02%) and solubility (from 40.13 to 35.39%) of the films. All films incorporated with EE-AP showed higher colorimetric parameters and opacity than the control film (p < 0.05). The DPPH radical scavenging ability of the Gel-CMC films was increased from 24.16 to 41.12, 57.21, and 63.47%, as the extract concentration increased. Active films presented excellent ultraviolet-visible light barrier properties. The antioxidant pigments (flavonoids and chlorophylls) were estimated spectrophotometrically through absorbance. In vitro tests indicated high effectiveness to inhibit the growth of Rhizopus stolonifer and Aspergillus niger. A preservation study indicated the absence of fungal development in berries over six days of storage. In conclusion, gelatin-carboxymethylcellulose films with EE-AP represent a potential option for active packaging and can preserve fresh fruit.

Influence of eight chosen essential oils in the vapor phase on the growth of Rhizopus stolonifer and Rhizopus lyococcus

This study aimed to evaluate the fungicidal effect of eight essential oils against five strains of the genus Rhizopus. Strains were obtained from various moldy foods, namely Rhizopus stolonifer KMi 383 from chestnut, R. stolonifer KMi 510 from strawberry, R. stolonifer KMi 511 from nectarine, R. stolonifer KMi 524 from cherry tomatoes, and R. lyococcus KMi 512 from blackberry. The essential oils (EO) used in this study were jasmine EO (extract from Jasminum officinale L.), bergamot EO (Mentha aquatica L. var. citrata (Her.) Fresen), bitter orange EO (from Citrus aurantium L.), grapefruit EO (Citrus paradisi Macfady), sweet flag EO (East Asian Calamus, from Acorus calamus L. var. angustatus Bes), star anise EO (from Illicium verum J.D.Hook), geranium EO (from Pelargonium graveolens), and lemongrass EO (from Cymbopogon citratus DC). The semi-quantitative composition of the essential oil samples was determined by gas chromatography coupled with mass spectrometry (GC-MS). The antifungal activity of essential oils against the strains of R. stolonifer and R. lyococcus was determined during 7 days, using the micro-atmosphere method (0.625 μL.mL-1 of air). Two essential oils, geranium and lemongrass, completely inhibited the growth of all isolates. Bitter orange essential oil inhibited the growth of all isolates of Rhizopus stolonifer, but isolate of Rhizopus lyococcus began to grow after four days of cultivation. In conclusion, certain essential oils are highly effective in the vapor phase. These could be used in further tests of their antifungal activity and could be used in the control of Rhizopus spp. or other fungal pathogens.

Chemical Profile and Antimicrobial Properties of Liquid and Vapor Phases of The Essential Oil of Cladanthus eriolepis: An Endemic Asteraceae Growing in The Moroccan Oases

The present study has been designed to evaluate the phytochemical quality and quantity of the essential oil (EO) extracted from Cladanthus eriolepis originated in Southern Moroccan oases and to examine its antimicrobial potential by the use of poison-food (PF) and volatile activity (VA) tests against four bacterial and five fungal agricultural pathogens. The analysis of the EO showed that camphor was the predominant constituent (37.02 %), followed by sabinene (10.26 %), α-pinene (6.29 %), p-cymene (6.13 %) and α-cadinol (5.57 %). The antimicrobial activity of C. eriolepis oil in vapor and liquid phases on the tested bacterial and fungal strains showed that Staphylococcus aureus ATCC 6538 was the most vulnerable, displaying the weakest development with a minimal bactericidal concentration (MBC) and minimal inhibitory concentration (MIC) of 0.156 mg mL-1 and 0.078 mg mL-1 respectively. Fusarium oxysporum f. sp. albedinis, Aspergillus brasiliensis, Rhizopus stolonifer, Penicillium expansum and Alternaria sp. were found to be susceptible to this EO, thus were partly repressed with 0.5 μL mL-1 of the liquid EO. Nevertheless, at the same concentration, mycelial growth of Rhizopus stolonifer and Alternaria sp. was completely inhibited by the vapor phase of the EO. The latter has a higher antifungal activity which can inhibit the growth of most tested fungi. This behavior of the vapor phase provides an interesting path forward for finding ways to apply this EO especially by fumigation in the control of post-harvest diseases.

Bacillomycin D inhibits growth of Rhizopus stolonifer and induces defense-related mechanism in cherry tomato.

The inhibitory effect of Bacillomycin D, a cyclic lipopeptide, on Rhizopus stolonifer colonization of cherry tomato was studied, and its possible mechanism of action was explored. Bacillomycin D showed a direct inhibitory effect on R. stolonifer spore germination and mycelial growth in vitro. It conferred both a direct inhibitory effect on R. stolonifer growth in cherry tomato in vivo and induced host resistance in cherry tomato. Moreover, Bacillomycin D treatment significantly increased the activities of plant defense-related enzymes, including chitinase (CHI), β-1,3-glucanase (GLU), phenylalanine ammonia-lyase (PAL), and peroxidase (POD). Real-time PCR (RT-PCR) showed that defense-related genes involved in the salicylic acid defense signaling pathway and genes encoding pathogenesis-related proteins were up-regulated in Bacillomycin D treatment. Furthermore, Bacillomycin D-C16 resulted in direct inhibition and a remarkable induced resistance to R. stolonifer which was higher than as induced by Bacillomycin D-C14. Together, the data indicated that Bacillomycin D can control the growth of R. stolonifer through both the direct inhibition of the fungus and the activation of defense-related genes and enzymes in cherry tomato.

Carvacrol and eugenol inhibit postharvest soft rot disease by enhancing defense response in peaches during storage

Peaches are in high demands because of their nutritional value and delicious flavor, but often become unmarketable due to the fungus infection. In this study, carvacrol and eugenol were used to preserve peaches. Rhizopus stolonifer growth was completely inhibited by carvacrol at 32 µl/Lair and eugenol at 64 µl/Lair. Carvacrol at 0.5 µl/Lair and eugenol at 1 µl/Lair significantly reduced the incidence and severity of soft rot decay in artificially inoculated peaches. Also, carvacrol and eugenol significantly reduced the natural incidence of soft rot disease and maintained high sensory acceptance and quality of peaches during storage. The activities of defense-related enzymes were enhanced by carvacrol and eugenol fumigation, and the contents of phenolics, flavonoids, lignin, and hydroxyproline-rich glycoprotein in these two oils treated fruit, were much higher than untreated control during storage. These observations indicted that carvacrol and eugenol could preserve peach fruit during postharvest storage. Practical applications Carvacrol and eugenol showed great potential application in the preservation of peach fruit during postharvest storage, exhibiting high antifungal activity against Rhizopus stolonifer and enhancing defense response to soft rot disease.

Bacterial iturins mediate biocontrol activity of Bacillus sp. against postharvest pear fruit‐rotting fungi

AbstractA potential antagonist, Bacillus sp. LYLB4 isolated from pear fruits, was tested for its antifungal activity against postharvest pear pathogens. LYLB4 had a remarkable antifungal effect on Botryosphaeria dothidea. Although it showed a weak inhibition effect on the growth of Rhizopus stolonifer on potato dextrose agar (PDA) plates, LYLB4 almost completely destroyed R. stolonifer during direct contact in potato dextrose broth (PDB). LYLB4 treatment was able to significantly reduce disease incidence (by 68.9% and 100%, respectively) and lesion diameter (by 68.7% and 100%, respectively) of ring rot caused by B. dothidea and soft rot caused by R. stolonifer in pears. LYLB4 also suppressed several other phytopathogens in vitro, suggesting a broad‐spectrum antagonistic activity against fungal pathogens. 16S rRNA and gyrA sequence analysis indicated that LYLB4 is closely related to B. velezensis. Genome mining indicated that LYLB4 had 11 secondary metabolites encoding clusters, but that the surfactin and fengycin gene clusters may not be functional because of a large deletion. Matrix‐assisted laser desorption ionization‐time of flight mass spectra (MALDI‐TOF‐MS) demonstrated that iturins were the major lipopeptides, and that C16/C17 Bacillomycin D synthesis was stimulated when LYLB4 was co‐cultured with B. dothidea compared to the control. Overall, these results demonstrate that the main biocontrol mechanism adopted by LYLB4 could be through the production of toxic metabolites and direct contact with pathogens.

Developing a methodology for identifying brown rot resistance in stone fruit

Assays were conducted to understand the effect of various factors involved with screening for resistance to Monilinia fructicola in stone fruit. First, the effect of maturity heterogeneity was determined in a set of fruit graded into three apparent maturity classes according to the IAD index for measurements taken with a DA-Meter. Second, different conidia concentrations, incubation times and M. fructicola strains were evaluated to optimize the methodology. Furthermore, the effects of fruit disinfection on M. fructicola, Penicillium expansum and Rhizopus stolonifer growth were studied. Finally, the developed methodology was applied to a set of commercial varieties of stone fruit to determine its suitability for identifying the level of susceptibility to brown rot. The results obtained indicated significant differences between wounded and non-wounded fruit, inoculum concentration and incubation time. The effect of strain aggressiveness was also confirmed, whereas, in general, no significant differences were observed among the fruit collected at the same harvest date. Our results also show that disinfection of fruit prior to inoculation had an effect on the infection process. In addition, the use of this methodology in commercial varieties of stone fruit allowed distinctions to be made among the levels of susceptibility to brown rot. Hence, the developed methodology could be applied to resistance screening in breeding programmes, as well as studying the genetic basis of brown rot resistance.

Inhibitory Effect of Ginger and Turmeric on Rhizopus stolonifer Growth on Bread

The inhibitory effect of ginger and turmeric was studied on the Rhizopus stolonifer growth on bread. Different ratios of ginger and turmeric were incorporated to bread dough formulation. The treatments were BG0 (control), BG1 (3% ginger), BG2 (4% ginger), BG3 (3% turmeric), BG4 (4% turmeric), BG5 (1.5% ginger + 1.5% turmeric) and BG6 (2% ginger + 2% turmeric). All the samples were analyzed physicochemically (moisture, ash, pH and water activity), microbiologically (colony count of Rhizopus stolonifer) and organoleptically (color, texture, flavor and overall acceptability). The results showed that overall moisture decreased (from 27.46 to 26.41), water activity aW (from 0.89 to 0.86), color (from 7.4 to 5.58), texture (from 6.94 to 5.34), flavor (from 7.75 to 5.54) and overall acceptability (from 7.38 to 5.48), while percent ash increased (from 0.84 to 0.86), pH (from 5.95 to 6.20) and microbial count of Rhizopus stolonifer (3.8×101 to 2×102). The highest mean value for ash was recorded for treatment BG4 (0.98), water activity in BG0 (0.91), moisture in BG0 (29.69), pH in BG4 (6.34) Microbial count in BG0 (1.5 × 102cfu/g), color in BG3 (6.98), texture in BG0 (7.04), flavor in BG0 (6.90) and overall acceptability in BG0 and BG3 (6.96). The overall results showed that BG3 gave the best inhibitory results against Rhizopus stolonifer as well as in physicochemical and sensory evaluation, while BG6 also presented better inhibitory results in microbial analysis but it was not satisfactory in terms of sensory characteristics.

Antibacterial Activity of Papaya Leaf Extracts Against Pathogenic Bacteria

It was reported that the extracts of papaya leaves could inhibit the growth of Rhizopus stolonifer. Antibacterial activity of Carica papaya leaf extracts on pathogenic bacteria was observed in this study. Papaya leaves were extracted by using maceration method and three kinds of solvents: ethanol, ethyl acetate, and hexane. Papaya leaf extracts were tested against Bacillus stearothermophilus, Listeria monocytogenes, Pseudomonas sp., and Escherichia coli by agar diffusion method. The objectives of this study were to determine extract ability against pathogenic bacteria, to observe the influence of pH, NaCl, and heat on extracts ability, and to observe extract ability against B. stearothermophilus spores. The data showed that ethyl acetate extract could inhibit B. stearothermophilus, L. monocytogenes, Pseudomonas sp., and E. coli. The extract activity was influenced by pH, and it was more effective in low pH. The extract activity was influenced by NaCl against B. stearothermophillus and E. coli. However, it was not influenced by NaCl in bioassay against L. monocytogenes and Pseudomonas sp. The extract activity was influenced by heating process against all the bacteria tested. The extracts inhibited B. stearothermophilus spores as well. Papaya leaves are potential natural anti-bacteria, which might be used in certain kinds of food.

Antioxidant, antifungal and antiviral activities of chitosan from the larvae of housefly, Musca domestica L.

Antioxidant activity of the chitosan from the larvae of Musca domestica L. was evaluated in two different reactive oxygen species assays, and inhibitory effects against seven fungi were also tested. The results showed that the chitosan had scavenging activity for hydroxyl and superoxide radicals which were similar to that of ascorbic acid. Also the chitosan exhibited excellent antifungal activity, especially in the low concentration, it could significantly inhibit the growth of Rhizopus stolonifer. Besides, antiviral results demonstrated that the chitosan could effectively inhibit the infection of AcMNPV and BmNPV. These results suggested that the chitosan from the larvae of housefly could be effectively used as a natural antioxidant to protect the human body from free radicals and retard the progress of many chronic diseases. Furthermore, the chitosan with antiviral and antifungal activity might provide useful information for antiviral breeding technology of economic insect and development of plant pathological control.

Inhibition of Spore Development and Mycelial Growth of Rhizopus stolonifer by Essential Oil of Satureja richingeri from Iran

There is a great interest in the use of natural antifungal compounds for the control of fungi such as Rhizopus stolonifer in the postharvest agricultural system and food industry. In this study, the inhibitory effect of essential oil extracted from Satureja richingeri and its major compound, Carvacrol, on spore development and mycelial growth of R. stolonifer was investigated. Mycelium exhibited higher sensitivity to the oil and Carvacrol than that observed for spores. Spore treatment with oil and Carvacrol for 2 and 3 h led to a complete inhibition of spore germination, after 4 h of incubation. However, continuing the incubation to 6 h resulted in germination of 4.67% of the spores treated with the oil but no germination was detected for those treated with Carvacrol. It could be concluded that treatment with S. richingeri essential oil for 3 h would extend the shelf life of agricultural product considerably via inhibition of spore germination.

Effect of nutrient status, pH, temperature and water potential on germination and growth of Rhizopus stolonifer and Gilbertella persicaria.

Effect of nutrient status, pH, temperature and water potential on germination and growth of Rhizopus stolonifer and Gilbertella persicaria.

Fungitoxic effects of extract from garlic (&lt;i&gt;Alium sativum&lt;/i&gt;) on the post harvest rot pathogens of yam and sweet potato

The effects of garlic extract on the post harvest rot pathogens of Yam and Sweet Potatoes were investigated. Rhizopus stolonifer, Botryodiplodia theobromae Aspergillus niger and Aspergillus flavus were found to be the cause of rot in yam and sweet potato. Both hot ethanol and mechanically extracted pathogens progressively inhibited their radial growth. At 20% concentration, there was no growth of Botryodiplodia theobromae and 62.9% and 68.8% inhibition of growth of Aspergillus niger and Aspergillus flavus. The radial growth of Rhizopus stolonifer was not affected at this concentration, but at 50% concentration, there was no growth of any of the fungi. International Journal of Natural and Applied Sciences Vol. 2 (4) 2006: pp. 405-408

Antibacterial, antifungal and antitubercular activity of (the roots of) Pelargonium reniforme (CURT) and Pelargonium sidoides (DC) (Geraniaceae) root extracts

Root extracts of Pelargonium reniforme CURT and Pelargonium sidoides DC were evaluated for antibacterial and antifungal assays using the agar dilution while antitubercular assays were done using the BACTEC method at concentrations ranging from 5 × 10 3 to 500.0 mg/L. The ethanol and acetone extracts of the roots of P. sidoides inhibited the growth of Haemophilus influenzae, Moraxella catarrhalis and Streptococcus pneumoniae at a concentration of 5 × 10 3 mg/L. Both acetone and ethanol extracts of P. reniforme and only the ethanol extract of P. sidoides inhibited the growth of Aspergillus niger and Fusarium oxysporum significantly at a concentration of 5 × 10 3 mg/L. Growth of Rhizopus stolonifer was suppressed by the ethanol extract of P. reniforme and P. sidoides at 5 × 10 3 and 1 × 10 3 mg/L, respectively. Acetone, chloroform and ethanol extracts of P. reniforme showed activity against M. tuberculosis exhibiting a minimum inhibitory concentration of 5 × 10 3 mg/L.

Development of selective media for the isolation and enumeration of Alternaria species from soil and plant debris

A new semi-selective medium, acidified weak potato-dextrose agar (AWPDA) with Mertect (active ingredient: thiabendazole), was developed for the isolation and enumeration of Alternaria species from samples of soil and plant debris. The medium was selected based on growth inhibition tests against Alternaria and several other commonly encountered saprobic fungi utilizing three antifungal agents, Botran (active ingredient: dichloran), Bayleton (active ingredient: triadimefon), and Mertect, and two basal media, acidified potato-dextrose agar (APDA) and AWPDA. Botran inhibited growth of Rhizopus stolonifer moderately, but had little effect on Cladosporium cladosporoides, Fusarium oxysporum, Penicillium chrysogenum, or Trichoderma harzianum. Bayleton inhibited growth of R. stolonifer and C. cladosporoides severely, and inhibited growth of F. oxysporum, P. chrysogenum, and T. harzianum moderately. Mertect inhibited growth of C. cladosporoides, F. oxysporum, P. chrysogenum, and T. harzianum completely, but had little or moderate effect on R. stolonifer. All three antifungal agents inhibited growth of Alternaria species slightly or moderately. The combination of Bayleton and Mertect inhibited growth of all fungi severely. A comparison of recovery rates of Alternaria from soil and plant debris samples on AWPDA with Mertect and weak potato-dextrose agar (WPDA) revealed that Alternaria spp. accounted for 63.6%-81.0% of recovered fungal isolates on AWPDA with Mertect as compared to 0.6%-2.7% of recovered isolates on WPDA. The AWPDA medium with Mertect exhibited superior selective growth of Alternaria species from samples of soil and plant debris, and will be useful in studies where the recovery and enumeration of Alternaria species is necessary.

High-oxygen and high-carbon dioxide containing atmospheres inhibit growth of food associated moulds.

The objective of this study was to determine the relationship between the growth of three foodborne fungi and high-oxygen modified atmosphere. Petri dishes were incubated in a series of connected flasks, which were placed in a climatized room and flushed continuously with the desired gas atmosphere. A combination of 80% oxygen and 20% carbon dioxide resulted in reduced growth of Rhizopus stolonifer, Botrytis cinerea and Penicillium discolor compared with ambient atmosphere conditions. Combining 80% oxygen and 20% carbon dioxide at 10 degrees C arrested growth of B. cinerea for 17 d while an elevated carbon dioxide concentration only inhibited growth up to 11 d. In addition, the peroxidase activity was doubled at 80% oxygen and decreased when 10% carbon dioxide was present. This study demonstrates the potential use of elevated oxygen levels in a modified atmosphere to inhibit food-associated mould growth.