Karim Rigalma

• PhD
• Université de Bretagne Occidentale

Penicillium camemberti is a domesticated species adapted to the dairy environment, which is used as adjunct cultures to ripen soft cheeses. A recent population genomics analysis on P. camemberti revealed that P. camemberti is a clonal lineage with two varieties almost identical genetically but with contrasting phenotypes in terms of growth, color,...

Filamentous fungi are used in the dairy industry as adjunct cultures in fermented products, but can also lead to food spoilage, waste and economic losses. The control of filamentous fungi with abiotic factors contributes to longer food shelf life and prevention of fungal spoilage. One of the main abiotic factors for controlling fungal growth in foo...

This study aimed at quantifying the impact of the concentration of four commercial sanitizers and temperature on mold spores inactivation. The sanitizers were based on the following fungicide molecules, ethanol (ARVO 21 SR), active chlorine (ARVO CLM 600), hydrogen peroxide (Nocolyse Food) and triamine (P3 Topax 960). Food plant spores were produce...

Due to the dissemination of airborne conidia and spores, molds can contaminate various surfaces. In the food industry sector, their presence and development can have health and economic implications. In order to control these undesirable microorganisms, various approaches can be used but the main one relies on the use of disinfectants. The objectiv...

Different strains of a given fungal species may display heterogeneous growth behavior in response to environmental factors. In predictive mycology, the consideration of such variability during data collection could improve the robustness of predictive models. Among food-borne fungi, Penicillium roqueforti is a major food spoiler species which is al...

This study aimed at assessing the impact of the physiological state of fungal spores on inactivation by sodium hypochlorite, 0.1% and 0.2% active chlorine, and 3% hydrogen peroxide. In this context, two physiological states were compared for 4 fungal species (5 strains). The first physiological state corresponded to fungal spores produced at 0.99 a...

The aim of this study was to assess the impact of the physiological state and intraspecific variability on the efficacy of 70% ethanol to inactivate conidia of Penicillium commune, used as a representative species of dairy product contaminants. Four physiological states were obtained by modifying the water activity during the production of conidia...

Although lupin anthracnose caused by Colletotrichum lupini is a significant threat for spring and winter lupin crops, it has been poorly studied so far. This study aimed at characterizing the (i) phylogenetic, (ii) morphological, and (iii) physiological diversity of collected isolates from anthracnose-affected lupins. The genetic identification of...

Modified atmosphere packaging (MAP) is commonly applied to extend food shelf-life. Despite growth of a wide variety of fungal contaminants has been previously studied in relation to modified-atmospheres, few studies aimed at quantifying the effects of dioxygen (O2) and carbon dioxide (CO2) partial pressures on conidial germination in solid agar med...

Topic: Physiology and metabolism - Introduction: In the cheese industry context, Mucor species exhibit an ambivalent behavior, as some species are essential technological organisms contributing to the required organoleptic characteristics of some cheeses while some others can be spoiling agents. The present study aimed at better understanding this...

Water activity (aw) is one of the most influential abiotic factors affecting fungal development in foods. The effects of aw reduction on conidial germination and radial growth are generally studied by supplementing culture medium with the non-ionic solute glycerol despite food aw can also depend on the concentration of ionic solutes such as sodium...

Colletotrichum is a fungal genera gathering numerous species causing anthracnose on a large host range and these pathogens are spread worldwide. Within the Colletotrichum acutatum complex, the filamentous fungus Colletotrichum lupini is specific to Lupins and responsible for the anthracnose disease, one of the major threats for Lupin crops.

Conidial germination and mycelial growth are generally studied with conidia produced under optimal conditions to increase conidial yield. Nonetheless, the physiological state of such conidia most likely differs from those involved in spoilage of naturally contaminated food. The present study aimed at investigating the impact of temperature, pH and...

The Mucor genus includes a large number of ubiquitous fungal species. In the dairy environment, some of them play a technological role providing typical organoleptic qualities to some cheeses while others can cause spoilage. In this study, we compared the effect of relevant abiotic factors for cheese production on the growth of six strains represen...

The genus Mucor belongs to the Mucoromycotina subphylum and Mucorales order. This genus includes a large number of ubiquitous fungal species. In the dairy environment, some of them play a technological role providing typical organoleptic qualities to some cheeses while others can cause undesirable effects including off-flavours, anomalous textures...

The Mucor genus includes ubiquitous species regularly encountered as contaminants of foodstuffs where they induce undesirable effects including off-flavours, anomalous textures or discolorations. In the cheesemaking context, some Mucor spp. are used as technological microorganisms contributing to the texture and the sensory characteristics of chees...

Le genre Mucor regroupe des espèces de champignons basaux ubiquistes présentes dans l’environnement mais aussi dans des matières premières et/ou des produits transformés. Dans le contexte fromager, et en fonction du fromage considéré, les Mucor n’ont pas le même rôle. Dans les fromages frais et à pâte molle (bûche de chèvre, Camembert), ils peuvent...

Le genre Mucor regroupe des espèces de champignons basaux ubiquistes présentes dans l’environnement mais aussi dans des matières premières et/ou des produits transformés. Dans le contexte fromager et en fonction du fromage considéré, les Mucor peuvent être assimilés à des microorganismes d’altération responsables de défauts de type « poil de chat »...

Le genre Mucor regroupe des espèces de champignons basaux ubiquistes présentes dans l’environnement mais aussi dans des matières premières et/ou des produits transformés. Dans le contexte fromager, et en fonction du fromage considéré, les Mucor peuvent être assimilés à des microorganismes d’altération, du fait par exemple de la formation de défauts...

The Mucor genus includes ubiquitous species found in the environment but also in raw materials and processed foodstuffs. Some species serve as technological microorganisms in various fermented products. In France, some Mucor spp. are used for the production of St. Nectaire and Tomme cheeses due to the typical organoleptic qualities they provide; wh...

The Mucor genus includes ubiquitous species found in the environment, but also in raw materials and foodstuffs. In the cheesemaking context, some Mucor spp. are used as technological microorganisms due to the organoleptic qualities they provide to some cheese (e.g. Tomme and St Nectaire cheeses), while on other cheeses they can cause spoilage. To d...

This work aimed first to compare 2 diets differing in their percentage of concentrate [low (LO): 30% concentrate vs. High (HI): 60% concentrate] by measuring simultaneously feeding behavior, rumen parameters, blood and plasma parameters, and milk yield and composition in 8 mid-lactation goats. The second aim was to study the interrelationships betw...

Le genre Mucor appartient au sous-phylum des Mucoromycotina, un groupe de champignons basaux par rapport aux champignons supérieurs. Ce genre regroupe des espèces ubiquistes puisqu’on les retrouve dans l’environnement, dans des prélèvements de sol (Farrow, 1954 ; Pandey & al., 1990 ; Domsch & al., 2007), d’air et de poussière (Bagy & Gohar 1988 ; B...

Stray voltage ( Keywords: ANIMAL WELFARE; CATTLE; PAST EXPERIENCE; STRAY VOLTAGE; STRESS; UNPREDICTABILITY Document Type: Research Article Publication date: August 1, 2011 $(document).ready(function() { var shortdescription = $(".originaldescription").text().replace(/\\&/g, '&').replace(/\\, '<').replace(/\\>/g, '>').replace(/\\t/g, ' ').replace(/\...

The effects of permanent or random exposure to stray voltage on a water trough were evaluated in growing–finishing Romane male lambs between the age of 13 and 19 weeks. Ninety lambs were assigned during two 6-week experimental periods to one of three treatments, with 30 animals in each treatment (15 per experimental period). The treatments were per...

The medium-term effects of permanent or random exposure to stray voltage applied to the water trough were evaluated on milk production and stress physiology in lactating dairy cows. Seventy-four Holstein cows were assigned during two 8-wk experimental periods to 1 of 3 treatments. The treatments were permanent exposure to voltage (PERM, 1.8 V, n=23...

Lors de l’application d’une tension électrique augmentée progressivement chaque jour, un seuil de réaction persistante de 2,3 V (3,5 mA) a été mis en évidence à court terme chez des génisses, malgré une forte variabilité individuelle. À moyen terme, une analyse multicritère a montré que l’exposition de vaches laitières, de manière permanente (prévi...

Besides the very important scientific research on the - still unproved - effects of ELF EMF on human health, some few studies have focused on possible effects of EMF on large farm animals such as pigs, cows and horses. Most of these were observational studies conducted in the 70's and 80's. They correspond to major developments of HV grids, and exp...

When heifers were exposed to an electrical current which voltage was increased daily, a short-term persistent reaction threshold of 2.3 V (3.5 mA) was observed, despite a large individual variability. In the medium-term, a multi-criteria experimental approach in dairy cows exposed to a permanent (predictable) or random (unpredictable) voltage of 1....

L’élevage des animaux de rente implique une utilisation croissante d’équipements électriques et électroniques ainsi que le recours à du matériel et à des structures métalliques qui sont autant de facteurs favorisant l’apparition des courants électriques parasites. Les tensions à l’origine de ces courants, généralement inférieures à 10 volts, sont d...

Modern farming techniques involve an increasing use of electrical and electronic equipment together with metallic features which can be responsible for stray-voltage. Stray-voltage, less than 10 volts, is often due to a faulty connection between the electrical circuit and the earth. Animals, due to a lower electrical resistance than humans, are mor...

The aim of this study was to compare rumen pH and time-budget in eight mid-lactation goats receiving two diets in a cross-over design (low-concentrate diet (L): 30% and high-concentrate diet (H): 60% concentrate). Feeding H increased daily intake (4.3 ± 0.08% v. 4.7 ± 0.08% of body weight for L and H, respectively) and daily milk production (3.01 ±...

The requirements for polyunsaturated fatty acids during brain development are high and in certain situations supply may be inadequate. Numerous studies in rodents have shown that a diet rich in linolenic acid improves learning ability and modifies emotional reactivity of offspring. Thirty-two goats received from 1.5 months before to 2 months after...