scholarly journals Effect of Temperature during Drying and Storage of Dried Figs on Growth, Gene Expression and Aflatoxin Production

Toxins ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 134
Author(s):  
Ana Isabel Galván ◽  
Alicia Rodríguez ◽  
Alberto Martín ◽  
Manuel Joaquín Serradilla ◽  
Ana Martínez-Dorado ◽  
...  
Keyword(s):  
Gene Expression ◽  
Aflatoxin Production ◽  
Effect Of Temperature ◽  
Mycotoxin Production ◽  
Industrial Processing ◽  
Factors Associated ◽  
Different Temperatures ◽  
Major Producer ◽  
Main Factors ◽  
And Storage

Dried fig is susceptible to infection by Aspergillus flavus, the major producer of the carcinogenic mycotoxins. This fruit may be contaminated by the fungus throughout the entire chain production, especially during natural sun-drying, post-harvest, industrial processing, storage, and fruit retailing. Correct management of such critical stages is necessary to prevent mould growth and mycotoxin accumulation, with temperature being one of the main factors associated with these problems. The effect of different temperatures (5, 16, 25, 30, and 37 °C) related to dried-fig processing on growth, one of the regulatory genes of aflatoxin pathway (aflR) and mycotoxin production by A. flavus, was assessed. Firstly, growth and aflatoxin production of 11 A. flavus strains were checked before selecting two strains (M30 and M144) for in-depth studies. Findings showed that there were enormous differences in aflatoxin amounts and related-gene expression between the two selected strains. Based on the results, mild temperatures, and changes in temperature during drying and storage of dried figs should be avoided. Drying should be conducted at temperatures >30 °C and close to 37 °C, while industry processing, storage, and retailing of dried figs are advisable to perform at refrigeration temperatures (<10 °C) to avoid mycotoxin production.

Modeling the effect of temperature on survival rate of Listeria monocytogenes in yogurt

2016 ◽  
Vol 19 (2) ◽  
pp. 317-324 ◽  
Author(s):  
J. Szczawiński ◽  
M.E. Szczawińska ◽  
A. Łobacz ◽  
A. Jackowska-Tracz
Keyword(s):  
Listeria Monocytogenes ◽  
Survival Rate ◽  
Storage Time ◽  
Ph Value ◽  
Effect Of Temperature ◽  
Natural Logarithm ◽  
Primary Model ◽  
Different Temperatures ◽  
Mathematical Equations ◽  
And Storage

Abstract The aim of the study was to (i) evaluate the behavior of Listeria monocytogenes in a commercially produced yogurt, (ii) determine the survival/inactivation rates of L. monocytogenes during cold storage of yogurt and (iii) to generate primary and secondary mathematical models to predict the behavior of these bacteria during storage at different temperatures. The samples of yogurt were inoculated with the mixture of three L. monocytogenes strains and stored at 3, 6, 9, 12 and 15°C for 16 days. The number of listeriae was determined after 0, 1, 2, 3, 5, 7, 9, 12, 14 and 16 days of storage. From each sample a series of decimal dilutions were prepared and plated onto ALOA agar (agar for Listeria according to Ottaviani and Agosti). It was found that applied temperature and storage time significantly influenced the survival rate of listeriae (p<0.01). The number of L. monocytogenes in all the samples decreased linearly with storage time. The slowest decrease in the number of the bacteria was found in the samples stored at 6°C (D-10 value = 243.9 h), whereas the highest reduction in the number of the bacteria was observed in the samples stored at 15°C (D-10 value = 87.0 h). The number of L. monocytogenes was correlated with the pH value of the samples (p<0.01). The natural logarithm of the mean survival/inactivation rates of L. monocytogenes calculated from the primary model was fitted to two secondary models, namely linear and polynomial. Mathematical equations obtained from both secondary models can be applied as a tool for the prediction of the survival/inactivation rate of L. monocytogenes in yogurt stored under temperature range from 3 to 15°C, however, the polynomial model gave a better fit to the experimental data.

Effect of temperature on growth, gene expression, and aflatoxin production by Aspergillus nomius isolated from Brazil nuts

2019 ◽  
Vol 36 (2) ◽  
pp. 173-180
Author(s):  
Nathália B. S. Yunes ◽  
Rodrigo C. Oliveira ◽  
Tatiana A. Reis ◽  
Arianne C. Baquião ◽  
Liliana O. Rocha ◽  
...  
Keyword(s):  
Gene Expression ◽  
Aflatoxin Production ◽  
Effect Of Temperature ◽  
Brazil Nuts ◽  
Aspergillus Nomius

Climate change factors and Aspergillus flavus: effects on gene expression, growth and aflatoxin production

2015 ◽  
Vol 8 (2) ◽  
pp. 171-179 ◽  
Author(s):  
Á Medina ◽  
A. Rodríguez ◽  
Y. Sultan ◽  
N. Magan
Keyword(s):  
Climate Change ◽  
Gene Expression ◽  
Water Stress ◽  
Aspergillus Flavus ◽  
Climatic Factors ◽  
Aflatoxin Production ◽  
Scientific Data ◽  
Effect Of Temperature ◽  
Mycotoxigenic Fungi ◽  
The Impact

The objectives of this study were to obtain scientific data on the impact that interactions between water stress (water activity (aw); 0.97, 0.95, 0.92), temperature (34, 37 °C) and CO2 exposure (350, 650, 1000 ppm) may have on the growth, gene expression of biosynthetic genes (aflD, aflR), and phenotypic aflatoxin B1 (AFB1) production by a type strain of Aspergillus flavus on a conducive medium. The study showed that while aw affected growth there was no statistically significant effect of temperature or CO2 exposure. The effect of these interacting factors on aflD and aflR gene expression showed that at 34 °C there was maximum relative expression of aflD under the control conditions (34 °C, 350 ppm) with a decrease in expression with elevated CO2 and water stress. For aflR expression at 34 °C, there was a significant increase in expression, but only at 0.92 aw and 650 ppm CO2. However, at 37 °C, there was a significant increase in expression of both aflD and aflR at 0.95 and 0.92 aw and 650 and 1000 ppm CO2. There was an associated increase in AFB1 in these treatments. In contrast, at 34 °C there were no significant differences for interacting treatments. This is the first study to examine these three-way interacting climatic factors on growth and mycotoxin production by a strain of A. flavus. This provides data that are necessary to help predict the real impacts of climate change on mycotoxigenic fungi.

scholarly journals Effect Of Temperature And Storage Time On The Nutritional Quality Of Olive Drupes: A Case Study

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
Enrico Finotti ◽  
Loretta Gambelli ◽  
Gioia Meysem Mili ◽  
Gabrielle Lo Feudo ◽  
Cinzia Benincasa ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Sensory Analysis ◽  
Nutritional Quality ◽  
Storage Time ◽  
Quality Parameters ◽  
Effect Of Temperature ◽  
Different Temperatures ◽  
And Storage

In this study we evaluated the effect of temperature and time storage on the quality parameters of mono cultivar olive oil drupes. In particular, analyses of total free phenols, fatty acids, lipophilic and hydrophilic antioxidant capacity, sensory analysis, at different temperatures and different times of post harvest storage, were performed. All data obtained have been singularly processed by Functional Mathematical Index (FMI).

5-hydroxymethyl furfural formation and reaction kinetics of different pekmez samples: effect of temperature and storage

2012 ◽  
Vol 8 (4) ◽  
Author(s):  
Rasim Alper Oral ◽  
Mahmut Dogan ◽  
Kemal Sarioglu ◽  
Ömer Said Toker
Keyword(s):  
Reaction Kinetics ◽  
Arrhenius Equation ◽  
Storage Period ◽  
Effect Of Temperature ◽  
Temperature Changes ◽  
Juniperus Communis ◽  
Hydroxymethyl Furfural ◽  
Different Temperatures ◽  
And Storage ◽  
Kinetics Of

Abstract Pekmez (molasses) is a traditional food commonly produced from grape and other kind of fruit juices by evaporation processes. In this study, 5-Hydroxymethylfurfural (HMF) level of various pekmez samples was investigated during storage at different temperatures. HMF content of apricot, mulberry, carob, grape, Juniperus communis pekmez changed from 133.0 ppm to 1060.5 ppm, from 88.2 to 1921.5 ppm, from 11.1 to 1153.6 ppm, from 75.5 to 2077.0 ppm, from 19.9 to 280.1 ppm throughout eight months storage period, respectively. Samples of pekmez from the Juniperus communis had the minimum k values for each temperature that means HMF formation in these samples were slower than other pekmez types. The kinetic data analysis for HMF formation during storage was performed and an Arrhenius equation was used to determine the effect of temperature on reaction kinetics of 5-HMF formation in pekmez samples. Ea values were found between 10.58–37.73 (kcal/mol). Apricot pekmez was found as the least sensitive sample to HMF formation resulted from temperature changes.

scholarly journals Histamine content in rennet ripening cheeses during storage at different temperatures and times

2018 ◽  
Vol 62 (1) ◽  
pp. 65-69 ◽  
Author(s):  
Anna Madejska ◽  
Mirosław Michalski ◽  
Marzena Pawul-Gruba ◽  
Jacek Osek
Keyword(s):  
Storage Time ◽  
Histamine Content ◽  
Effect Of Temperature ◽  
Fermented Foods ◽  
Histamine Concentration ◽  
Rp Hplc ◽  
Suitable Temperature ◽  
Different Temperatures ◽  
The Mean ◽  
And Storage

AbstractIntroductionIn recent years, there has been a great interest in biogenic amines such histamine, as they are associated with the quality and safety of some kinds of fermented foods. The aim of this study was to evaluate the effect of temperature and storage time on the content of histamine in cheeses.Material and MethodsSamples of mould and hard cheeses were examined with RP-HPLC with an organic-aqueous mobile phase containing acidic buffer and chaotropic salt. The samples were stored either at 22 ± 2°C for 42 days (mould and hard cheeses) or at 4 ± 2°C for 112 days (mould cheeses) and 133 days (hard cheeses).ResultsThe mean total histamine content in cheeses stored at 22°C was higher than the content in those stored at 4°C, with the highest concentrations found in Gorgonzola Piccante cheese (730.47 mg/kg). Histamine concentration in some types of cheeses exceeded the toxic threshold dose, indicating that after long or inadequately cool storage they may not be safe for consumers.ConclusionTo protect cheeses from contamination with histamine-producing bacteria and to safeguard consumers from poisoning, factors conducive to this amine’s formation should be minimised during cheese processing. Suitable temperature and time during storage of cheeses are recommended to avoid the intoxication. Monitoring of this toxin in food is necessary to ensure safety of consumers.

scholarly journals Effect of Drying Temperatures and Exposure Times on Aspergillus flavus Growth and Aflatoxin Production on Artificially Inoculated Hazelnuts

2020 ◽  
Vol 83 (7) ◽  
pp. 1241-1247 ◽  
Author(s):  
SILVIA VALENTE ◽  
GIOVANNA ROBERTA MELONI ◽  
SIMONA PRENCIPE ◽  
NICOLA SPIGOLON ◽  
MARCO SOMENZI ◽  
...  
Keyword(s):  
Aspergillus Flavus ◽  
Aflatoxin Production ◽  
Aflatoxin Contamination ◽  
Drying Process ◽  
Fungal Development ◽  
Drying Temperature ◽  
Different Temperatures ◽  
Aflatoxin B2 ◽  
And Storage

ABSTRACT Aspergillus flavus may colonize hazelnuts and produce aflatoxins in the field and during storage. The main purpose of this study was to investigate the influence of drying temperature and exposure times on the viability of A. flavus and its ability to produce aflatoxins during the drying process and storage. Hazelnuts were inoculated with A. flavus and dried at different temperatures to reach 6% moisture content and a water activity (aw) of 0.71, a commercial requirement to avoid fungal development and aflatoxin contamination. Hazelnuts were dried at 30, 35, 40, 45, and 50°C and subsequently stored at 25°C for 14 days. After drying at 30, 35, and 40°C, increased amounts of A. flavus were evident, with the highest concentration occurring after drying at 35°C ([6.1 ± 2.4] × 106A. flavus CFU/g). At these temperatures, aflatoxins were detected only at 30 and 35°C. Aflatoxins, however, were present at higher levels after drying at 30°C, with concentrations of 1.93 ± 0.77 μg/g for aflatoxin B1 (AFB1) and 0.11 ± 0.04 μg/g for aflatoxin B2 (AFB2). After 14 days of storage, the highest A. flavus concentration and the highest levels of mycotoxins were detected in samples treated at 35°C ([8.2 ± 2.1] × 107A. flavus CFU/g and 9.30 ± 1.58 μg/g and 0.89 ± 0.08 μg/g for AFB1 and AFB2, respectively). In hazelnuts dried at 45 or 50°C, no aflatoxins were found either after drying or storage, and a reduction of A. flavus viable conidia was observed, suggesting that a shorter and warmer drying is essential to guarantee nut safety. The lowest temperature that guarantees the lack of aflatoxins should be selected to maintain the organoleptic quality of hazelnuts. Therefore, 45°C should be the recommended drying temperature to limit A. flavus growth and aflatoxin contamination on hazelnuts. HIGHLIGHTS

Presence of genes associated with adhesion, invasion, and toxin production in Campylobacter jejuni isolates and effect of temperature on their expression

2019 ◽  
Vol 65 (4) ◽  
pp. 253-260 ◽  
Author(s):  
Mauricéia Greici de Oliveira ◽  
Caroline Rizzi ◽  
Vanessa Galli ◽  
Graciela Volz Lopes ◽  
Louise Haubert ◽  
...  
Keyword(s):  
Gene Expression ◽  
Campylobacter Jejuni ◽  
Virulence Genes ◽  
Virulence Gene ◽  
Toxin Production ◽  
Effect Of Temperature ◽  
Pcr Assay ◽  
Different Temperatures ◽  
Differential Gene ◽  
Expression Evaluation

The aims of this study were to evaluate the presence of genes associated with adhesion (cadF), invasion (ciaB), and cytotoxin production (cdtA, cdtB, and cdtC) among Campylobacter jejuni isolates from a poultry slaughterhouse and to investigate the effect of different temperatures on the expression of these virulence-associated genes. A total of 88 C. jejuni isolates from cecum, liver, chicken carcasses, chilled water, and scalding water were submitted to PCR assay for detection of virulence genes. Representative isolates were selected for gene expression evaluation at 37 and 42 °C, according to their virulence gene profile and genotypic typing. All C. jejuni isolates carried the five virulence-associated genes, which play an important role in the infectious process. Differential gene expression by RT–qPCR was observed among C. jejuni isolates at 37 and 42 °C. The expression levels at 37 °C showed upregulation of the ciaB, cdtA, cdtB, and cdtC genes in five isolates, with the exception of ciaB for isolate 4. At 42 °C, upregulation was observed for ciaB and cdtC, cdtA and cdtB, and cadF in four, three, and two isolates, respectively. The C. jejuni isolates expressed the virulence genes evaluated, and the expression is gene- and isolate-dependent and varied according the temperature.

scholarly journals Ecological characterisation of the Colombian entomopathogenic nematode Heterorhabditis sp. SL0708

2013 ◽  
Vol 73 (2) ◽  
pp. 239-243 ◽  
Author(s):  
MC Mejia-Torres ◽  
A Sáenz
Keyword(s):  
Galleria Mellonella ◽  
Storage Temperature ◽  
Entomopathogenic Nematode ◽  
Effect Of Temperature ◽  
Different Temperatures ◽  
Valle Del Cauca ◽  
And Storage

The entomopathogenic nematode Heterorhabditis sp. SL0708 (Rhabditida: Heterorhabditidae) isolated from soil in Alcalá, Valle del Cauca (Colombia) was characterised ecologically using Galleria mellonella larvae (L) (Pyralidae: Galleriinae) as hosts. The effect of temperature on the viability, infectivity and reproduction, and of moisture on infectivity and storage in liquid were evaluated in infective juveniles (IJs). Significant differences were found in the viability, infectivity and reproduction of the IJs at different temperatures. No nematodes were recovered at 5 °C and 10 °C, and at 35 °C no infectivity was observed. Average daily nematode recovery was best at 25 °C, and survival of the IJs was low in substrates presenting 13% moisture. The optimal storage temperature for Heterorhabditis sp. SL0708 was between 20 °C and 30 °C, keeping its infectivity for up to 8 weeks.

scholarly journals Staphylococcus aureus and enterotoxin A relative gene expression in beef meat after lactic acid treatment and storage at different temperatures

2020 ◽  
Vol 23 (3) ◽  
pp. 378-388
Author(s):  
H. A. A. Abdelghany ◽  
H. M. B. A. Zaki ◽  
K. S. Tolba ◽  
N. A. Yassin
Keyword(s):  
Gene Expression ◽  
Staphylococcus Aureus ◽  
Lactic Acid ◽  
Control Sample ◽  
Food Poisoning ◽  
Fresh Meat ◽  
Relative Expression ◽  
Different Temperatures ◽  
And Storage ◽  
Zero Time

The Staphylococcus aureus enterotoxin A (sea) is the toxin mostly involved in Staphylococcus aureus (S. aureus) food poisoning. In this study, the effect of different lactic acid (LA) concentrations (LA 1% and 2%) and temperatures (4 oC, 25 oC, and 37 oC) on S. aureus growth and relative sea expression in fresh meat cuts were studied. Real-Time RT-PCR used to determine the relative sea expression. Fresh meat cuts were inoculated with 105 CFU/g of S. aureus producing enterotoxin A. S. aureus growth and relative sea expression were regularly tested for 48 hours. The growth of S. aureus was decreased by one log CFU/g than control sample using 1% LA and 2% LA 2% (5.32 ± 3.76 log CFU/g, 4.38 ± 3.00 log CFU/g and 4.54 ± 3.18 log CFU/g respectively) at zero time. Relative expression of the sea gene in both LA concentrations was lower than control. Moreover, both lactic acid concentrations had effect on relative sea gene expression at all examined hours, especially at 4 oC compared to control samples. The higher the lactic acid concentration, the lower the S. aureus enterotoxin A relative expression was.

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