The search for alternatives for the control of microbiological contamination in foods has been the object of study in different scientific areas. This study aimed to evaluate the efficiency of lemon grass (Cymbopogon citratus) essential oil in controlling the growth of the fungus Aspergillus flavus in three types of analysis: first, by in vitro tests, in essential oil doses between 0.2 and 1.0 μL/ml; second, by serial microdilution to determine the minimum inhibitory concentration, in doses between 0.1 and 1.2 μL/mL; and third, by inhibition of fungal growth in corn kernels contaminated using essential oil doses of 0.4, 0.7, and 1.0 μL/mL, in the incubation times of 14, 28, and 42 days. The in vitro tests showed that the essential oil controlled the fungus from doses of 0.6 μL/mL, but the dose of 1.0 μL/mL controlled 100% growth until day eight of incubation, from which it decreased. The minimum inhibitory concentration for the microdilution analysis was 0.9 μL/mL. The evaluation of the corn kernels for all doses of essential oil and times tested showed 100% inhibition of the fungal growth.

Respiratory abnormalities among workers at coffee roasting and packaging facilities have already been reported; however, little is known about microbiological contamination inside coffee production facilities. This study intends to assess the microbial contamination (fungi and bacteria) in two coffee industries from Brazil with a multi-approach protocol for sampling and for subsequent analyses using four main sources of samples: filtering respiratory protection devices (FRPD) used by workers, settled dust, electrostatic dust cloths (EDC) and coffee beans. The fungal contamination in the assessed industries was also characterized through the molecular detection of toxigenic species and antifungal resistance. Total bacteria contamination presented the highest values in FRPD collected from both industries (7.45 × 104 CFU.m−2; 1.09 × 104 CFU.m−2). Aspergillus genera was widespread in all the environmental samples collected and sections with clinical relevance (Fumigati) and with toxigenic potential (Nigri and Circumdati) were recovered from FRPD. Circumdati section was observed in 4 mg/mL itraconazole. Sections Circumdati (EDC, coffee beans and settled dust) and Nidulantes (EDC, coffee beans and FRPD) were detected by qPCR. Some of the targeted Aspergillus sections that have been identified microscopically were not detected by qPCR and vice-versa. Overall, this study revealed that microbial contamination is a potential occupational risk in the milling stage and should be tackled when assessing exposure and performing risk assessment. In addition, a multi-sampling campaign should be the approach to follow when assessing microbial contamination and FRPD should be included in this campaign. Occupational exposure to mycotoxins should be considered due to high fungal diversity and contamination. A One Health approach should address these issues in order to prevent consumption of coffee crops and beans infected by fungi and, more specifically, to avoid widespread azole resistance.

The drying of coffee by means of fixed layer dryers has been widely used by Brazilian coffee growers. However, high gradients of water content formed in these dryers are frequently reported, as well as the presence of microorganisms. The present work was developed with the purpose of monitoring the performance of these dryers and their effect on the final quality of the product, comparing to an adaptation made in conventional fixed layer dryers. During drying, the following characteristics were monitored at various points in the drying chamber: temperature of drying air, intergranular air, exhaust air, and ambient air; relative humidity of the drying air, the ambient air, and the exhaust air and the water content of the product at different points and heights in the drying chamber (0.12; 0.36 and 0.60 m). Among the dry product evaluations, color analysis and microbiological analysis were performed. According to the results obtained, drying with inversion of the airflow resulted in a water content gradient of 0.4% (b.u.), while conventional drying caused a gradient of 8% (b.u.). Regarding the color of the product in the different drying managements, drying with airflow inversion resulted in lighter products. For the microbiological analysis, fungi of the genera Cladosporium, Fusarium, and Aspergillus were found, among others. The average incidence of these fungi was higher in conventional drying samples than in fixed layer drying with inversion of airflow.

The objective of this work was to evaluate the antifungal activity of the essential oil of Cymbopogon citratus in the control of Aspergillus brasiliensis in analysis in vitro and in stored corn kernels. Two in vitro tests were carried out. One of them, by diffusion in agar and the other by microdilution in wells. The concentrations used for the agar diffusion assay were 0.2; 0.4; 0.6; 0.8 and 1.0 µL mL-1. The concentrations used for the microdilution test were: 0.1; 0.2; 0.3; 0.4; 0.5; 0.6; 0.7; 0.8; 0.9; 1.0 and 1.2 µL   mL-1. The mycelial growth was evaluated over time, using the Scott-Knott test at 5% significance. From the results obtained, it was verified that the application of the essential oil of Cymbopogon citratus interferes significantly in the fungal development of the species Aspergillus brasiliensis. The microdilution test in wells was used in a qualitative way, indicating absence of growth in doses from 0.8 µL mL-1. For the corn grain test, the essential oil dosages of 0.5; 0.8 and 1.0 µL mL-1 and were stored for 42 days. There was no significant difference in the different doses of essential oil over the storage period for this assay.

The Cymbopogon genus is widely studied for its medicinal characteristics, which are recognized and used worldwide. However, there is a need to study the drying kinetics, hygroscopic balance and the color change of Cymbopogon flexuosus leaves by varying the drying temperature. The objective of this work was to study the drying kinetics of Indian grass leaves, to adjust a model among those existing in the literature that best represents the behavior of the sorption isotherm, as well as to analyze the effect of the drying process on the color of the leaves. The Indian grass leaves were cut to a length of 0.2 m and submitted to drying air temperatures of 35, 45, 55 and 70 ºC in a fixed layer mechanical dryer. For the study of the hygroscopic phenomenon, temperatures of 20, 30, 55 and 70 ºC were used with water activities between 10.75 and 85.11%. The model that best represented the drying curves was the Midilli model with an R² of 0.99. The model that best represented the hygroscopic balance curve of Indian grass leaves was that of Modified GAB with R² of 0.94. As the drying air temperature increased, the samples darkened at temperatures above 45 ºC.

Garlic is a product of nutritional importance, with medicinal character, much used, and can be dehydrated for better conservation. However, there is a need for further research to characterize the drying kinetics. The objective of this work was to study drying kinetics of Brazilian garlic (Allium sativum L.), as well as to analyze the effect of the process on the resulting color of garlic. The garlic bulbs were cut into thin slices thicknesses of 2.10-3 and 3.10-3 m, subjected to a drying air temperature of 35, 45, 55 and 70 °C in a mechanical dryer of fixed layer with forced convection. A non-linear regression analysis was performed by the Quase-Newton method to fit 12 mathematical models to the experimental data. The Midilli equation was the one that best characterized all the drying temperatures, for the values collected. The effective diffusivity varied from 1.62 . 10-10  to 6.04 . 10-10 m2 s-1 and 1.60 .  10-10 to 8.36 . 10-10  m2 s-1 at the thickness of 2 . 10-3 and 3 . 10-3 m, respectively. With the increase of the drying air temperature, the samples were darkened in all thicknesses at 70 °C and for the cut thickness of 3 . 10-3 m at 55 °C, also L constant and the hue angle were decreased.

The medicinal plants of genus Lippia is used worldwide for its medicinal characteristics. However, there is a need to study the drying kinetics and hygroscopic balance of Lippia gracilis leaves by varying the drying temperature. The objective of this work was to study the drying kinetics of Lippia gracilis as well as to adjust a model among those existing in the literature that best represents the behavior of the sorption isotherm. The rosemary leaves were processed and submitted to drying air temperatures of 40, 50, 60, and 70 ºC in a fixed layer mechanical dryer. For the study of the hygroscopic phenomenon, temperatures of 20, 30, 55, and 70 ºC were used with water activities between 0.11 and 0.81. The model that best represented the drying curves was the Midilli model with an R² of 99.60. The model that best represented the hygroscopic balance curve of Lippia gracilis was that of Sabbah with an R² of 93.33%.

The storage of agricultural products is of great importance in maintaining product quality between harvest and commercialization. The use of numerical and computational techniques, such as the finite element method (FEM) and computational fluid dynamics (CFD), allows the analysis and simulation of systems that involve heat transfer, as is the case of grain storage. A computational model based on these techniques that satisfactorily represents a real system was used to test and to analyze decision alternatives without the need for real experimentation. In this study, we sought to study the behavior of the temperature of a mass of stored mocha coffee beans by using computational techniques, as requested by the private sector. The coffee was stored for 6 months in two types of environments: a cooled environment between 15 and 18 °C by using an air temperature control equipment used for artificial cooling and a natural environment. A computational model was developed to simulate the heat transfer process for both types of storage. In the comparison of the temperature distribution during storage from simulation results and for experimental results, an overall mean relative error of 2.34% was obtained for coffee stored in a natural environment, and that of 5.74% was obtained for coffee stored in a cooled environment.