1
|
Koňuchová M, Boháčiková A, Valík Ľ. Characterisation of the surface growth of Mucor circinelloides in cheese agar media using predictive mathematical models. Heliyon 2024; 10:e30812. [PMID: 38765159 PMCID: PMC11101853 DOI: 10.1016/j.heliyon.2024.e30812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 04/15/2024] [Accepted: 05/06/2024] [Indexed: 05/21/2024] Open
Abstract
The main objective of this work was to characterise the mycelial growth of Mucor circinelloides, one of the fungal contaminants that appear frequently in the artisan cheese production environment. The study uses primary Baranyi and Huang models to compare their parameters and predict M. circinelloides on cheese-based medium (CBA) under diverse environmental conditions (temperature range from 6 to 37 °C and 0 and 1 % NaCl concentration). However, the Baranyi model consistently estimated longer lag phases and higher surface growth rates (sgr) than the Huang model; both models showed adequate best-fit performance (exactly with the mean coefficient of determination R2 = (0.993 ± 0.020 × 10-1). The groups of primary growth parameters were analysed against temperature using the cardinal model (CM) with the following main outputs. The optimal surface growth rates (sgropt) on CBA were 6.8 and 6.5 mm/d calculated with the Baranyi and Huang models, respectively. They were reduced by approximately 46 % on the surface of the agar medium when 1 % NaCl was added. Topt was estimated in a very narrow range of 32.1-32.5 °C from both primary sgr data sets (0 % and 1 % NaCl). Similarly, Tmax values of 37.2 °C and 37.3 °C were estimated for the Baranyi and Huang models, respectively; however, they decreased at 2 °C in CBA with 1 % NaCl (Tmax = 35.1 °C). The application of CM for sgr provided an estimation of the parameter Tmin with negative values that are considered only as a theoretical output. The results provide insight into the modelling and prediction of fungi growth as a function of time and salt concentration, including the times to detect visible mycelial growth of Mucor circinelloides. The mere quantification of this phenomenon can be useful for practice. Adjusting the frequency of the cheese surface washing step with a salt solution at the early stage of ripening properly can prevent the growth of not only fast fungal growers.
Collapse
Affiliation(s)
- Martina Koňuchová
- Institute of Food Sciences and Nutrition, Faculty of Chemical and Food Technology, Slovak University of Technology Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovakia
| | - Agáta Boháčiková
- Institute of Food Sciences and Nutrition, Faculty of Chemical and Food Technology, Slovak University of Technology Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovakia
| | - Ľubomír Valík
- Institute of Food Sciences and Nutrition, Faculty of Chemical and Food Technology, Slovak University of Technology Bratislava, Radlinského 9, SK-812 37, Bratislava, Slovakia
| |
Collapse
|
2
|
Hyphal growth of Penicillium rubens in changing relative humidity. Appl Microbiol Biotechnol 2021; 105:5159-5171. [PMID: 34095972 PMCID: PMC8236038 DOI: 10.1007/s00253-021-11343-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 04/25/2021] [Accepted: 05/09/2021] [Indexed: 11/18/2022]
Abstract
Abstract When considering mold prevention strategies, the environmental conditions in which fungi grow need to be taken into consideration. This environment is often characterized by a time-dependent relative humidity, and porous substrate. Growth has mainly been investigated in steady-state experiments. Therefore, the goal of this study is to understand the hyphal growth of Penicillium rubens on porous gypsum, under dynamic humidity conditions. Spores of P. rubens were inoculated on porous gypsum containing nutrients, and placed in a small incubation chamber, allowing for microscopic hyphal observation. The relative humidity in this chamber varied multiple times between a high (close to 100%) and low value (35%, 55%, or 75%). The hyphae reacted to a lowered relative humidity by an immediate growth stop and dehydration. When the relative humidity was increased again, the hyphae re-hydrated and three responses were found: regrowing after approximately 4 h, after a time equal to the germination time, or no regrowth at all. No substantial regrowth was found for fluctuations faster than 4 h. This time-scale was found for multiple decreases in relative humidity, and has been reported for the first time. Key points • Hyphae restart growth after a characteristic time of approximately 4 h. • Relative humidity fluctuations of 3 h can suppress hyphal growth. • Hyphae do not regrow after a severe desiccation and short periods of high humidity. Supplementary Information The online version contains supplementary material available at 10.1007/s00253-021-11343-6.
Collapse
|
3
|
|
4
|
Koňuchová M, Valík Ľ. Modelling the Radial Growth of Geotrichum candidum: Effects of Temperature and Water Activity. Microorganisms 2021; 9:532. [PMID: 33807629 PMCID: PMC7999232 DOI: 10.3390/microorganisms9030532] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 02/24/2021] [Accepted: 03/02/2021] [Indexed: 11/16/2022] Open
Abstract
Modelling the growth of microorganisms in relation to environmental factors provides quantitative knowledge that can be used to predict their behaviour in foods. For this reason, the effects of temperature and water activity (aw) adjusted with NaCl on the surface growth of two isolates and one culture strain of Geotrichum candidum were studied. A dataset of growth parameters obtained from almost 600 growth curves was employed for secondary modelling with cardinal models (CMs). The theoretical minimal temperature resulting from the modelling of the mycelium proliferation rate ranged from -5.2 to -0.4 °C. Optimal and maximal temperatures were calculated and found to have narrow ranges of 25.4 to 28.0 °C and 34.2 to 37.6 °C, respectively. Cardinal aw values associated with radial growth (awmin from 0.948-0.960 and awopt from 0.992-0.993) confirmed the salt sensitivity of the species. Model goodness-of-fit was evaluated by the coefficient of determination R2, which ranged from 0.954 to 0.985, and RMSE, which ranged from 0.28 to 0.42. Substantially higher variability accompanied the lag time for growth modelling than the radial growth rate modelling despite the square root transformation of the reciprocal lag phase data (R2 = 0.685 to 0.808). Nevertheless, the findings demonstrate that the outputs of growth modelling can be applied to the quantitative evaluation of the roles of G. candidum in fresh cheese spoilage as well as the ripening of Camembert-type cheeses or various artisanal cheeses. Along with validation, the interactions with lactic acid bacteria can be included to improve the predictions of G. candidum in the future.
Collapse
Affiliation(s)
- Martina Koňuchová
- Department of Nutrition and Food Quality Assessment, Institute of Food Science and Nutrition, Faculty of Chemical and Food Technology, Slovak University of Technology in Bratislava, Radlinskeho 9, SK-812 37 Bratislava, Slovakia;
| | | |
Collapse
|
5
|
Ruijten P, Huinink HP, Adan OCG. Penicillium rubens germination on desiccated and nutrient-depleted conditions depends on the water activity during sporogenesis. Fungal Biol 2020; 124:1058-1067. [PMID: 33213786 DOI: 10.1016/j.funbio.2020.10.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2020] [Revised: 10/08/2020] [Accepted: 10/14/2020] [Indexed: 10/23/2022]
Abstract
Fungal growth often appears in a surrounding where water and nutrients are scarce. The impact of this environment during sporogenesis on subsequent growth is often neglected. This study investigates the effect of water availability during sporogenesis on subsequent early growth. Therefore, a carbon-depleted substrate was constructed. Humidity is then the only parameter of interest. The water conditions during sporogenesis, and during subsequent growth, were varied. This is a stressing environment: no carbon source is present, and water provided solely via the vapour. The lag time, tl, and initial growth rate, μfp, of the germ tubes were monitored. The effect of aw history on germination and initial growth depends on the RH of the environment. Only at low RH do spores produced at low aw have a smaller tl and higher μfp compared to those grown at high aw. This result was remarkably pronounced when the substrate was also made hydrophobic: growth only occurred when spores were developed at low aw and placed in high RH. Spores grown on lowered aw attract more water. It is hypothesized that this attraction affects subsequent growth behaviour, and is the reason why growth on hydrophobic glass only prevails in the condition of high RH and lowered aw history. We demonstrate the influence of cultivation conditions on germination, which becomes more pronounced in a more desiccated environment.
Collapse
Affiliation(s)
- Philip Ruijten
- Department of Applied Physics, Eindhoven University of Technology, 5612, AZ, Eindhoven, the Netherlands
| | - Hendrik P Huinink
- Department of Applied Physics, Eindhoven University of Technology, 5612, AZ, Eindhoven, the Netherlands.
| | - Olaf C G Adan
- Department of Applied Physics, Eindhoven University of Technology, 5612, AZ, Eindhoven, the Netherlands; Netherlands Organization for Applied Scientific Research (TNO), High Tech Campus 25, 5656, AE, Eindhoven, the Netherlands
| |
Collapse
|
6
|
Sandoval-Contreras T, IÑiguez-Moreno M, Garrido-SÁnchez L, Ragazzo-SÁnchez JA, NarvÁez-Zapata JA, Ascencio F, CalderÓn-Santoyo M. Predictive Model for the Effect of Environmental Conditions on the Postharvest Development of Colletotrichum gloeosporioides Strains Isolated from Papaya (Carica papaya L.). J Food Prot 2020; 83:1495-1504. [PMID: 32236559 DOI: 10.4315/jfp-19-493] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Accepted: 03/31/2020] [Indexed: 11/11/2022]
Abstract
ABSTRACT Colletotrichum species are the most important postharvest spoilage fungi of papaya fruit. The objective of this research was to evaluate the effect of temperature and relative humidity on growth rate and time for growth to become visible of five strains of Colletotrichum gloeosporioides isolated from papaya fruit in a complex medium. As a primary model, the radial growth rates were estimated using the Baranyi and Roberts model in papaya agar. The Solver MS Excel function was used to obtain the time to visible mycelium (tv). Secondary models obtained with the Rosso et al. cardinal model of inflection were applied to describe the effect of temperature on the growth rate (μ). The Arrhenius-Davey model was used to model tv. The obtained models seem to be satisfactory for describing both μ and tv. The relative humidity had an effect on μ and tv for all tested C. gloeosporioides isolates, but no model accurately described the behavior of the fungus. External validation of models was performed with papaya fruit. Growth models were developed with the same models used in vitro. The bias and the accuracy factors as indices for performance evaluation of predictive models in food microbiology as a function of temperature and RH were 1.22 and 1.33, respectively, for μ and 1.18 and 1.62, respectively, for tv, indicating accurate predictions. The supply chain of papaya is complex and requires constant conditions, and poor conditions can result in damage to the fruit. Knowledge of the behavior of C. gloeosporioides on papaya fruit and application of the developed models in the supply chain will help to establish transport control strategies to combat these fungi. This research has contributed to development of the first models of growth for C. gloeosporioides in Mexico. HIGHLIGHTS
Collapse
Affiliation(s)
- Teresa Sandoval-Contreras
- Tecnológico Nacional de México/Instituto Tecnológico de Tepic, Av. Tecnológico #2595, C.P. 63175 Tepic, Nayarit, México
| | - Maricarmen IÑiguez-Moreno
- Tecnológico Nacional de México/Instituto Tecnológico de Tepic, Av. Tecnológico #2595, C.P. 63175 Tepic, Nayarit, México
| | - Luis Garrido-SÁnchez
- Instituto Tecnológico y de Estudios Superiores de Occidente, Periférico Sur Manuel Gómez Morín #8585, C.P. 45604 Tlaquepaque, Jalisco, México
| | - Juan Arturo Ragazzo-SÁnchez
- Tecnológico Nacional de México/Instituto Tecnológico de Tepic, Av. Tecnológico #2595, C.P. 63175 Tepic, Nayarit, México
| | - JosÉ Alberto NarvÁez-Zapata
- Instituto Politécnico Nacional, Centro de Biotecnología Genómica, Col. Narciso Mendoza, Reynosa, Tamaulipas, México
| | - Felipe Ascencio
- Centro de Investigaciones Biológicas del Noroeste. Av. Instituto Politécnico Nacional 195, Playa Palo de Santa Rita Sur, C.P. 23096 La Paz, Baja California Sur, México
| | - Montserrat CalderÓn-Santoyo
- Tecnológico Nacional de México/Instituto Tecnológico de Tepic, Av. Tecnológico #2595, C.P. 63175 Tepic, Nayarit, México.,(ORCID: https://orcid.org/0000-0002-8744-1815 [M.C.S.])
| |
Collapse
|
7
|
Lane Paixão dos Santos J, Samapundo S, Van Impe J, Sant’Ana AS, Devlieghere F. Effect of sugar concentration (°Brix) and storage temperature on the time to visible growth of individual ascospores of six heat-resistant moulds isolated from fruit products. Food Control 2020. [DOI: 10.1016/j.foodcont.2019.106880] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
|
8
|
Buehler A, Martin N, Boor K, Wiedmann M. Evaluation of biopreservatives in Greek yogurt to inhibit yeast and mold spoilage and development of a yogurt spoilage predictive model. J Dairy Sci 2018; 101:10759-10774. [DOI: 10.3168/jds.2018-15082] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 08/06/2018] [Indexed: 11/19/2022]
|
9
|
dos Santos JLP, Silva BS, Furtado MM, Morassi LL, Vermeulen A, Sant’Ana AS. The application of growth-no growth models to directly assess the stability of wholemeal multigrain bread towards Penicillium paneum LMQA-002 and Paecilomyces variotii LMQA-001. Lebensm Wiss Technol 2018. [DOI: 10.1016/j.lwt.2018.07.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
|
10
|
Santos JL, Samapundo S, Gülay SM, Van Impe J, Sant'Ana AS, Devlieghere F. Inter- and intra-species variability in heat resistance and the effect of heat treatment intensity on subsequent growth of Byssochlamys fulva and Byssochlamys nivea. Int J Food Microbiol 2018; 279:80-87. [DOI: 10.1016/j.ijfoodmicro.2018.04.035] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2018] [Revised: 04/09/2018] [Accepted: 04/19/2018] [Indexed: 01/08/2023]
|
11
|
Aldars-García L, Marín S, Sanchis V, Magan N, Medina A. Assessment of intraspecies variability in fungal growth initiation of Aspergillus flavus and aflatoxin B 1 production under static and changing temperature levels using different initial conidial inoculum levels. Int J Food Microbiol 2018; 272:1-11. [PMID: 29482078 DOI: 10.1016/j.ijfoodmicro.2018.02.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 01/06/2018] [Accepted: 02/11/2018] [Indexed: 11/24/2022]
Abstract
Intraspecies variability in fungal growth and mycotoxin production has important implications for food safety. Using the Bioscreen C we have examined spectrophotometrically intraspecies variability of A. flavus using 10 isolates under different environments, including temperature shifts, in terms of growth and aflatoxin B1 (AFB1) production. Five high and five low AFB1 producers were examined. The study was conducted at 5 isothermal conditions (from 15 to 37 °C) and 4 dynamic scenarios (between 15 and 30 °C). The experiments were carried out in a semisolid YES medium at 0.92 aw and two inoculum levels, 102 and 103 spores/mL. The Time to Detection (TTD) of growth initiation was determined and modelled as a function of temperature through a polynomial equation and the model was used to predict TTD under temperature upshifts conditions using a novel approach. The results obtained in this study have shown that a model can be developed to describe the effect of temperature upshifts on the TTD for all the studied isolates and inoculum levels. Isolate variability increased as the growth conditions became more stressful and with a lower inoculum level. Inoculum level affected the intraspecies variability but not the repeatability of the experiments. In dynamic conditions, isolate responses depended both on the temperature shift and, predominantly, the final temperature level. AFB1 production was highly variable among the isolates and greatly depended on temperature (optimum temperature at 30-35 °C) and inoculum levels, with often higher production with lower inoculum. This suggests that, from an ecological point of view, the potential isolate variability and interaction with dynamic conditions should be taken into account in developing strategies to control growth and predicting mycotoxin risks by mycotoxigenic fungi.
Collapse
Affiliation(s)
- Laila Aldars-García
- Food Technology Dept, XaRTA-UTPV, Agrotecnio Center, University of Lleida, Spain.
| | - Sonia Marín
- Food Technology Dept, XaRTA-UTPV, Agrotecnio Center, University of Lleida, Spain.
| | - Vicente Sanchis
- Food Technology Dept, XaRTA-UTPV, Agrotecnio Center, University of Lleida, Spain.
| | - Naresh Magan
- Applied Mycology Group, Environment and AgriFood Theme, Cranfield University, Cranfield, Bedford MK43 0AL, UK.
| | - Angel Medina
- Applied Mycology Group, Environment and AgriFood Theme, Cranfield University, Cranfield, Bedford MK43 0AL, UK.
| |
Collapse
|
12
|
Nguyen Van Long N, Vasseur V, Couvert O, Coroller L, Burlot M, Rigalma K, Mounier J. Modeling the Effect of Modified Atmospheres on Conidial Germination of Fungi from Dairy Foods. Front Microbiol 2017; 8:2109. [PMID: 29163403 PMCID: PMC5671599 DOI: 10.3389/fmicb.2017.02109] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2017] [Accepted: 10/16/2017] [Indexed: 11/13/2022] Open
Abstract
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 medium. In the present study, an original culture method was developed, allowing microscopic monitoring of conidial germination under modified-atmospheres in static conditions. An asymmetric model was utilized to describe germination kinetics of Paecilomyces niveus, Mucor lanceolatus, Penicillium brevicompactum, Penicillium expansum, and Penicillium roquefoti, using two main parameters, i.e., median germination time (τ) and maximum germination percentage (Pmax ). These two parameters were subsequently modeled as a function of O2 partial pressure ranging from 0 to 21% and CO2 partial pressure ranging from 0.03 to 70% (8 tested levels for both O2 and CO2). Modified atmospheres with residual O2 or CO2 partial pressures below 1% and up to 70%, respectively, were not sufficient to totally inhibit conidial germination,. However, O2 levels < 1% or CO2 levels > 20% significantly increased τ and/or reduced Pmax , depending on the fungal species. Overall, the present method and results are of interest for predictive mycology applied to fungal spoilage of MAP food products.
Collapse
Affiliation(s)
- Nicolas Nguyen Van Long
- Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, ESIAB, Université de Brest, EA 3882, Plouzané, France
| | - Valérie Vasseur
- Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, ESIAB, Université de Brest, EA 3882, Plouzané, France
| | - Olivier Couvert
- Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, UMT Spore Risk, ESIAB, Université de Brest, EA 3882, Quimper, France
| | - Louis Coroller
- Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, UMT Spore Risk, ESIAB, Université de Brest, EA 3882, Quimper, France
| | - Marion Burlot
- Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, ESIAB, Université de Brest, EA 3882, Plouzané, France
| | - Karim Rigalma
- Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, ESIAB, Université de Brest, EA 3882, Plouzané, France
| | - Jérôme Mounier
- Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, IBSAM, ESIAB, Université de Brest, EA 3882, Plouzané, France
| |
Collapse
|
13
|
Risk assessment of fungal spoilage: A case study of Aspergillus niger on yogurt. Food Microbiol 2017; 65:264-273. [DOI: 10.1016/j.fm.2017.03.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 03/09/2017] [Accepted: 03/10/2017] [Indexed: 11/21/2022]
|
14
|
Sandoval-Contreras T, Marín S, Villarruel-López A, Gschaedler A, Garrido-Sánchez L, Ascencio F. Growth Modeling of Aspergillus niger Strains Isolated from Citrus Fruit as a Function of Temperature on a Synthetic Medium from Lime (Citrus latifolia T.) Pericarp. J Food Prot 2017; 80:1090-1098. [PMID: 28574305 DOI: 10.4315/0362-028x.jfp-16-408] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Molds are responsible for postharvest spoilage of citrus fruits. The objective of this study was to evaluate the effect of temperature on growth rate and the time to visible growth of Aspergillus niger strains isolated from citrus fruits. The growth of these strains was studied on agar lime medium (AL) at different temperatures, and growth rate was estimated using the Baranyi and Roberts model (Int. J. Food Microbiol. 23:277-294, 1994). The Rosso et al. cardinal model with inflexion (L. Rosso, J. R. Lobry, S. Bajard, and J. P. Flandrois, J. Theor. Biol. 162:447-463, 1993) was used as a secondary model to describe the effect of temperature on growth rate and the lag phase. We hypothesized that the same model could be used to calculate the time for the mycelium to become visible (tv) by substituting the lag phase (1/λ and 1/λopt) with the time to visible colony (1/tv-opt and 1/tv), respectively, in the Rosso et al. MODEL High variability was observed at suboptimal conditions. Extremes of temperature of growth for A. niger seem to have a normal variability. For the growth rate and time tv, the model was satisfactorily compared with results of previous studies. An external validation was performed in lime fruits; the bias and accuracy factors were 1.3 and 1.5, respectively, for growth rate and 0.24 and 3.72, respectively, for the appearance time. The discrepancy may be due to the influence of external factors. A. niger grows significantly more slowly on lime fruit than in culture medium, probably because the nutrients are more easily available in medium than in fruits, where the peel consistency may be a physical barrier. These findings will help researchers understand the postharvest behavior of mold on lime fruits, host-pathogen interactions, and environmental conditions infecting fruit and also help them develop guidelines for future work in the field of predictive mycology to improve models for control of postharvest fungi.
Collapse
Affiliation(s)
- T Sandoval-Contreras
- 1 Centro de Investigaciones Biológicas del Noroeste, A.C. Av. Instituto Politécnico Nacional 195, 23097 La Paz, Baja California Sur, México
| | - S Marín
- 2 Ciéncia i Tecnologia Agrària i Alimentària, Departament de Tecnologia d'Aliments, Universitat de Lleida. Av. Rovira Roure 191, 25198 Lleida, Spain
| | - A Villarruel-López
- 3 Centro Universitario de Ciencias Exactas e Ingenierías, Universidad de Guadalajara, Marcelino García Barragán 145, 44430, Guadalajara, Jalisco, México
| | - A Gschaedler
- 4 Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco, A.C. Camino Arenero 1227, 45019 Zapopan, Jalisco, México
| | - L Garrido-Sánchez
- 5 Instituto Tecnológico de Estudios Superiores de Occidente, A.C. Periférico Sur Manuel Gómez Morín 8585, 45604 Tlaquepaque, Jalisco, México
| | - F Ascencio
- 1 Centro de Investigaciones Biológicas del Noroeste, A.C. Av. Instituto Politécnico Nacional 195, 23097 La Paz, Baja California Sur, México
| |
Collapse
|
15
|
Aldars-García L, Sanchis V, Ramos AJ, Marín S. Single vs multiple-spore inoculum effect on growth kinetic parameters and modeled probabilities of growth and aflatoxin B1 production of Aspergillus flavus on pistachio extract agar. Int J Food Microbiol 2017; 243:28-35. [PMID: 27940413 DOI: 10.1016/j.ijfoodmicro.2016.11.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2016] [Revised: 11/11/2016] [Accepted: 11/28/2016] [Indexed: 10/20/2022]
Abstract
The objective of the present study was to assess the differences in modeled growth/AFB1 production probability and kinetic growth parameters for Aspergillus flavus inoculated as single spores or in a concentrated inoculation point (~500 spores). The experiment was carried out at 25°C and at two water activities (0.85 and 0.87) on pistachio extract agar (3%). Binary data obtained from growth and AFB1 studies were modeled using linear logistic regression analysis. The radial growth curve for each colony was fitted to a linear model for the estimation of the lag phase for growth and the mycelial growth rate. In general, radial growth rate and lag phase for growth were not normally distributed and both of them were affected by the inoculation type, with the lag phase for growth being more affected. Changing from the multiple spore to the single spore inoculation led to a delay of approximately 3-5days on the lag phase and higher growth rates for the multiple spore experiment were found. The same trend was observed on the probability models, with lower predicted probabilities when colonies came up from single spores, for both growth and AFB1 production probabilities. Comparing both types of models, it was concluded that a clear overestimation of the lag phase for growth occurred using the linear model, but only in the multiple spore experiment. Multiple spore inoculum gave very similar estimated time to reach some set probabilities (t10, t50 and t100) for growth or AFB1 production due to the abruptness of the logistic curve developed. The observed differences suggest that inoculum concentration greatly affects the outcome of the predictive models, the estimated times to growth/AFB1 production being much earlier for the concentrated inoculum than for a single spore colony (up to 9days). Thus the number of spores used to generate data in predictive mycology experiments should be carefully controlled in order to predict as accurately as possible the fungal behavior in a foodstuff.
Collapse
Affiliation(s)
- Laila Aldars-García
- Food Technology Dept., XaRTA-UTPV, Agrotecnio Center, University of Lleida, Spain.
| | - Vicente Sanchis
- Food Technology Dept., XaRTA-UTPV, Agrotecnio Center, University of Lleida, Spain.
| | - Antonio J Ramos
- Food Technology Dept., XaRTA-UTPV, Agrotecnio Center, University of Lleida, Spain.
| | - Sonia Marín
- Food Technology Dept., XaRTA-UTPV, Agrotecnio Center, University of Lleida, Spain.
| |
Collapse
|
16
|
Aldars-García L, Sanchis V, Ramos AJ, Marín S. Time-course of germination, initiation of mycelium proliferation and probability of visible growth and detectable AFB1 production of an isolate of Aspergillus flavus on pistachio extract agar. Food Microbiol 2016; 64:104-111. [PMID: 28213013 DOI: 10.1016/j.fm.2016.12.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2016] [Revised: 12/16/2016] [Accepted: 12/20/2016] [Indexed: 12/20/2022]
Abstract
The aim of this work was to assess the temporal relationship among quantified germination, mycelial growth and aflatoxin B1 (AFB1) production from colonies coming from single spores, in order to find the best way to predict as accurately as possible the presence of AFB1 at the early stages of contamination. Germination, mycelial growth, probability of growth and probability of AFB1 production of an isolate of Aspergillus flavus were determined at 25 °C and two water activities (0.85 and 0.87) on 3% Pistachio Extract Agar (PEA). The percentage of germinated spores versus time was fitted to the modified Gompertz equation for the estimation of the germination parameters (geometrical germination time and germination rate). The radial growth curve for each colony was fitted to a linear model for the estimation of the apparent lag time for growth and the growth rate, and besides the time to visible growth was estimated. Binary data obtained from growth and AFB1 studies were modeled using logistic regression analysis. Both water activities led to a similar fungal growth and AFB1 production. In this study, given the suboptimal set conditions, it has been observed that germination is a stage far from the AFB1 production process. Once the probability of growth started to increase it took 6 days to produce AFB1, and when probability of growth was 100%, only a 40-57% probability of detection of AFB1 production was predicted. Moreover, colony sizes with a radius of 1-2 mm could be a helpful indicator of the possible AFB1 contamination in the commodity. Despite growth models may overestimate the presence of AFB1, their use would be a helpful tool for producers and manufacturers; from our data 5% probability of AFB1 production (initiation of production) would occur when a minimum of 60% probability of growth is observed. Legal restrictions are quite severe for these toxins, thus their control from the early stages of contamination throughout the food chain is of paramount importance.
Collapse
Affiliation(s)
- Laila Aldars-García
- Food Technology Dept, XaRTA-UTPV, Agrotecnio Center, University of Lleida, Spain.
| | - Vicente Sanchis
- Food Technology Dept, XaRTA-UTPV, Agrotecnio Center, University of Lleida, Spain.
| | - Antonio J Ramos
- Food Technology Dept, XaRTA-UTPV, Agrotecnio Center, University of Lleida, Spain.
| | - Sonia Marín
- Food Technology Dept, XaRTA-UTPV, Agrotecnio Center, University of Lleida, Spain.
| |
Collapse
|
17
|
|
18
|
Kalai S, Anzala L, Bensoussan M, Dantigny P. Modelling the effect of temperature, pH, water activity, and organic acids on the germination time of Penicillium camemberti and Penicillium roqueforti conidia. Int J Food Microbiol 2016; 240:124-130. [PMID: 27090813 DOI: 10.1016/j.ijfoodmicro.2016.03.024] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2015] [Revised: 03/13/2016] [Accepted: 03/21/2016] [Indexed: 10/22/2022]
Abstract
In this study, the influence of environmental factors on the germination time of Penicillium camemberti and Penicillium roqueforti conidia was evaluated. To do so, the effects of i/temperature, pH, water activity, and ii/organic acids were determined using models based on i/cardinal values, and ii/minimum inhibitory concentration (MIC) respectively. Cardinal values for germination of conidia were not observed to be species dependent. Minimum temperatures were estimated to be below the freezing point, with an optimum of 26.9°C, and a maximum of 33.5°C. For both species, minimal and optimal aw values were found to be 0.83 and 0.99, respectively, while for pH these values corresponded to 2.9, and 5.6. MIC values could not be determined for lactic acid because conidia of both species germinated in up to 1M concentrations, the highest concentration tested. At pH5.6, P. camemberti (MIC=0.197M) was more sensitive to propionic acid than P. roqueforti (MIC=0.796M).
Collapse
Affiliation(s)
- Safaa Kalai
- UMR PAM A 02.102, Laboratoire des Procédés Microbiologiques et Biotechnologiques, Université de Bourgogne-Franche Comté, Agro-Sup Dijon, 1 Esplanade Erasme, 21000 Dijon, France
| | - Lexane Anzala
- UMR PAM A 02.102, Laboratoire des Procédés Microbiologiques et Biotechnologiques, Université de Bourgogne-Franche Comté, Agro-Sup Dijon, 1 Esplanade Erasme, 21000 Dijon, France
| | - Maurice Bensoussan
- UMR PAM A 02.102, Laboratoire des Procédés Microbiologiques et Biotechnologiques, Université de Bourgogne-Franche Comté, Agro-Sup Dijon, 1 Esplanade Erasme, 21000 Dijon, France
| | - Philippe Dantigny
- UMR PAM A 02.102, Laboratoire des Procédés Microbiologiques et Biotechnologiques, Université de Bourgogne-Franche Comté, Agro-Sup Dijon, 1 Esplanade Erasme, 21000 Dijon, France; Université de Brest, EA 3882, Laboratoire Universitaire de Biodiversité et Ecologie Microbienne, ESIAB, Technopôle Brest-Iroise, 29280 Plouzané, France.
| |
Collapse
|
19
|
Dagnas S, Gougouli M, Onno B, Koutsoumanis KP, Membré JM. Modeling red cabbage seed extract effect on Penicillium corylophilum: Relationship between germination time, individual and population lag time. Int J Food Microbiol 2015; 211:86-94. [PMID: 26188372 DOI: 10.1016/j.ijfoodmicro.2015.07.008] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 06/14/2015] [Accepted: 07/05/2015] [Indexed: 11/16/2022]
Abstract
The inhibitory effect of a red cabbage seed extract on germination time, individual (single spore) and population lag time of Penicillium corylophilum was studied. First, to compare the biological variability of single spore germination and lag times under stressful conditions, data were collected at levels of red cabbage seed extract varying from 0 to 10 mg/g (150 spores observed in each trial of germination, ca 50 spores in each individual lag experiment). Experiments were performed on malt agar at 25 °C, pH 5.2, aw 0.99. The data, without any transformation, were statistically analyzed; several probability distribution functions were used to fit the cumulated germination times and the individual lag times of spores. In both cases, the best fit was obtained with the Normal distribution. In parallel, lag times at the population level (ca 2000 spores per trial) were collected for the same range of plant extract. Not surprisingly, the difference between individual and population lag times could be explained by a stochastic process. More interestingly, it was shown that under stressful conditions, the population lag time did not correspond to the time required for germination of 95% of spores, but to a much longer time. Finally, it was deduced from the statistical analysis, completed by microscopic observations, that the plant extract affected mainly the hyphal elongation (and then the lag time) and not the germination. Next, secondary models were developed to quantify the effect of red cabbage seed extract on the median of germination times, individual and population lag times. The Minimum Inhibitory Concentrations (MICs) were estimated. It was shown that the red cabbage seed extract MIC for P. corylophilum lag time did not depend on the inoculum load. Application of the secondary models allowed us to conclude that under the conditions of our experiment, the addition of 10 mg/g of red cabbage seed extract enabled extension of lag time to two weeks.
Collapse
Affiliation(s)
- Stéphane Dagnas
- L'Université Nantes Angers Le Mans, Oniris, Nantes F-44322, cedex 3, France
| | - Maria Gougouli
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Bernard Onno
- L'Université Nantes Angers Le Mans, Oniris, Nantes F-44322, cedex 3, France
| | - Konstantinos P Koutsoumanis
- Laboratory of Food Microbiology and Hygiene, Department of Food Science and Technology, School of Agriculture, Aristotle University of Thessaloniki, Thessaloniki 54124, Greece
| | - Jeanne-Marie Membré
- Institut National de la Recherche Agronomique, UMR1014 Sécurité des Aliments Microbiologie, Nantes F-44307, France; L'Université Nantes Angers Le Mans, Oniris, Nantes F-44322, cedex 3, France.
| |
Collapse
|
20
|
Dagnas S, Gauvry E, Onno B, Membré JM. Quantifying Effect of Lactic, Acetic, and Propionic Acids on Growth of Molds Isolated from Spoiled Bakery Products. J Food Prot 2015; 78:1689-98. [PMID: 26319723 DOI: 10.4315/0362-028x.jfp-15-046] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The combined effect of undissociated lactic acid (0 to 180 mmol/liter), acetic acid (0 to 60 mmol/liter), and propionic acid (0 to 12 mmol/liter) on growth of the molds Aspergillus niger, Penicillium corylophilum, and Eurotium repens was quantified at pH 3.8 and 25°C on malt extract agar acid medium. The impact of these acids on lag time for growth (λ) was quantified through a gamma model based on the MIC. The impact of these acids on radial growth rate (μ) was analyzed statistically through polynomial regression. Concerning λ, propionic acid exhibited a stronger inhibitory effect (MIC of 8 to 20 mmol/liter depending on the mold species) than did acetic acid (MIC of 23 to 72 mmol/liter). The lactic acid effect was null on E. repens and inhibitory on A. niger and P. corylophilum. These results were validated using independent sets of data for the three acids at pH 3.8 but for only acetic and propionic acids at pH 4.5. Concerning μ, the effect of acetic and propionic acids was slightly inhibitory for A. niger and P. corylophilum but was not significant for E. repens. In contrast, lactic acid promoted radial growth of all three molds. The gamma terms developed here for these acids will be incorporated in a predictive model for temperature, water activity, and acid. More generally, results for μ and λ will be used to identify and evaluate solutions for controlling bakery product spoilage.
Collapse
Affiliation(s)
- Stéphane Dagnas
- L'Université Nantes Angers Le Mans, Oniris, Nantes F-44322 cedex 3, France
| | - Emilie Gauvry
- L'Université Nantes Angers Le Mans, Oniris, Nantes F-44322 cedex 3, France
| | - Bernard Onno
- L'Université Nantes Angers Le Mans, Oniris, Nantes F-44322 cedex 3, France
| | - Jeanne-Marie Membré
- L'Université Nantes Angers Le Mans, Oniris, Nantes F-44322 cedex 3, France; Institut National de la Recherche Agronomique, UMR1014 Sécurité des Aliments et Microbiologie, Nantes F-44307, France.
| |
Collapse
|