Effect of water activity and relative air humidity on the growth of Penicillium chrysogenum thom, Aspergillus repens (Corda) Sacc., and Trichoderma viride Pers. isolated from living spaces

The ratio of ‘bound’ and ‘free’ water plays an important role in the studies of staling of various baked confectionery products. Gingerbread with fruit filling is a traditional flour confectionery product with intermediate moisture, which causes transfer processes during storage. Temperature, relative humidity, light exposure, mechanical stress, and pressure affect the staling speed of such confectionery products. The shelf life of raw gingerbread was increased from 10–20 days to more than two months, which caused microbiological deterioration during storage. Moisture transfer between the filling and the crumb increases water activity and ruins the capillary structure of gingerbread during storage, thus significantly increasing the risk of microbiological damage. The present research featured the changes in the mass fraction of moisture and water activity of individual parts of raw gingerbread with fruit filling during storage at different temperatures and relative air humidity. The samples were packed in a 40-micron polypropylene film. During storage, the mass fraction of moisture and water activity may change in various parts of the product, which can lead to their molding. In this case, starch degradation processes led to the destruction of the structure and a decrease in the content of mechanically-bound moisture, as well as to the release of ‘free’ water and an increase in water activity. As a result, the risk of molding increased significantly. The water activity increased from 0.71 to 0.79 on the sample surface after six weeks of storage at 30°C and a 40% of equilibrium relative humidity. A set of experiments in microbiological indicators revealed no signs of molding in the freshly prepared samples. After one month of storage, the amount of mold reached 10 CFU/g. The quantity of mesophilic aerobic and facultative anaerobic microorganisms in different parts of the crumb increased from 3×10 to 9×102 CFU/g and in the filling – from 1×10 to 2.3×103 CFU/g. After two months of storage, the amount of mold reached more than 103 COE/g, which greatly exceeds safety norms. As the relative air humidity increased from 30% to 40%, the moisture transfer rate between the products and the environment was reduced by half. As a result, the shelf life decreased by 1–2 weeks. The research also studied the patterns of moisture transfer processes in summer and winter conditions. The research results contribute to the development of technology and shelf life forecasting for complex flour confectionery products with intermediate moisture.

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Effect of water activity on the growth of fungi isolated from „muesli“ components

Acta periodica technologica ◽

10.2298/apt1344031d ◽

2013 ◽

pp. 31-37

Author(s):

Gordana Dimic ◽

Suncica Kocic-Tanackov ◽

Zeljko Maletic ◽

Irena Suturovic

Keyword(s):

Aspergillus Niger ◽

Water Activity ◽

Colony Formation ◽

Penicillium Chrysogenum ◽

Maximal Growth ◽

Effect Of Water ◽

Moisture Conditions ◽

Growth Of Fungi

The effect of water activity (aw) (0.85-0.97) on the growth of Aspergillus niger, A. flavus, Penicillium chrysogenum, P. brevicompactum and Eurotium herbariorum was examined. The growth of A. niger was lower than that of A. flavus at aw of 0.89 and 0.85. A. niger was the least tolerant of reduced moisture, and low aw (0.85) could prevent colony formation in 5 days. P. brevicompactum was less sensitive to reduced moisture conditions than P. chrysogenum. The maximal growth of E. herbariorum was observed at the level of 0.89 aw. Among the tested fungi, E. herbariorum appeared to be best adapted to the conditions of low aw.

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Visco-elastic changes of vocal fold mucosa related to high and low relative air humidity

Clinical Otolaryngology ◽

10.1046/j.1365-2273.2000.00358-27.x ◽

2000 ◽

Vol 25 (4) ◽

pp. 329-330

Author(s):

R.J.B. Hemler ◽

G.H. Wieneke ◽

P.H. Dejonckere

Keyword(s):

Vocal Fold ◽

Air Humidity ◽

Relative Air Humidity

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Clinical, epidemiological and climatic factors related to the occurrence of cutaneous leishmaniasis in an endemic area in northeastern Brazil

Brazilian Journal of Biology ◽

10.1590/1519-6984.224937 ◽

2020 ◽

Author(s):

R. S. Oliveira ◽

K. B. A. Pimentel ◽

M. L. Moura ◽

C. F. Aragão ◽

A. S. Guimarães-e-Silva ◽

...

Keyword(s):

Cutaneous Leishmaniasis ◽

Climatic Factors ◽

Wide Distribution ◽

Northeastern Brazil ◽

Public Health Issue ◽

Air Humidity ◽

Disease Occurrence ◽

Relative Air Humidity ◽

Age Range ◽

And Control

Abstract Cutaneous leishmaniasis (CL) is a neglected tropical disease with a wide distribution in the Americas. Brazil is an endemic country and present cases in all states. This study aimed to describe the occurrence, the underlying clinical and epidemiological factors, and the correlation of climatic variables with the frequency of reported CL cases in the municipality of Caxias, state of Maranhão, Brazil. This is a retrospective and descriptive epidemiological study based on data extracted from the Brazilian Information System of Diseases Notification, from 2007 to 2017. Maximum and minimum temperature, precipitation, and relative air humidity data were provided by the Brazilian National Institute of Meteorology. A total of 201 reported autochthonous CL cases were analyzed. The predominance of cases was observed in males (70.1%). The age range between 31 and 60 years old was the most affected, with 96 cases (47.9%). Of the total number of registered cases, 38.8% of the affected individuals were engaged in agriculture-related activities. The georeferenced distribution revealed the heterogeneity of disease occurrence, with cases concentrated in the Western and Southern regions of the municipality. An association was detected between relative air humidity (monthly mean) and the number of CL cases per month (p = 0.04). CL continues to be a concerning public health issue in Caxias. In this context, there is a pressing need to strengthen measures of prevention and control of the disease through the network of health services of the municipality, considering local and regional particularities.

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Responses of Rice Growth to Day and Night Temperature and Relative Air Humidity—Leaf Elongation and Assimilation

Plants ◽

10.3390/plants10010134 ◽

2021 ◽

Vol 10 (1) ◽

pp. 134

Author(s):

Sabine Stuerz ◽

Folkard Asch

Keyword(s):

Leaf Area ◽

Leaf Growth ◽

Crop Growth ◽

Air Humidity ◽

Leaf Elongation ◽

Night Temperature ◽

Relative Air Humidity ◽

Leaf Area Expansion ◽

Plant Level ◽

Area Expansion

Predictions of future crop growth and yield under a changing climate require a precise knowledge of plant responses to their environment. Since leaf growth increases the photosynthesizing area of the plant, it occupies a central position during the vegetative phase. Rice is cultivated in diverse ecological zones largely differing in temperature and relative air humidity (RH). To investigate the effects of temperature and RH during day and night on leaf growth, one variety (IR64) was grown in a growth chamber using 9 day/night regimes around the same mean temperature and RH, which were combinations of 3 temperature treatments (30/20 °C, 25/25 °C, 20/30 °C day/night temperature) and 3 RH treatments (40/90%, 65/65%, 90/40% day/night RH). Day/night leaf elongation rates (LER) were measured and compared to leaf gas exchange measurements and leaf area expansion on the plant level. While daytime LER was mainly temperature-dependent, nighttime LER was equally affected by temperature and RH and closely correlated with leaf area expansion at the plant level. We hypothesize that the same parameters increasing LER during the night also enhance leaf area expansion via shifts in partitioning to larger and thinner leaves. Further, base temperatures estimated from LERs varied with RH, emphasizing the need to take RH into consideration when modeling crop growth in response to temperature.

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The Effect of Water Activity and theawControlling Solute on Spore Germination ofBacillus stearothermophilus

Journal of Applied Bacteriology ◽

10.1111/j.1365-2672.1981.tb00898.x ◽

1981 ◽

Vol 50 (2) ◽

pp. 335-349 ◽

Cited By ~ 11

Author(s):

G. D. ANAGNOSTOPOULOS ◽

H. S. SIDHU

Keyword(s):

Water Activity ◽

Spore Germination ◽

Effect Of Water ◽

Ofbacillus Stearothermophilus

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Relationship between preterm birth and air pollution in Santos, Sao Paulo, Brazil

European Journal of Public Health ◽

10.1093/eurpub/ckaa166.111 ◽

2020 ◽

Vol 30 (Supplement_5) ◽

Author(s):

M E L Brandao ◽

B A L F Braga ◽

M L C Martins ◽

P L A A Pereira

Keyword(s):

Air Pollution ◽

Preterm Birth ◽

Air Pollutants ◽

First Trimester ◽

Sao Paulo ◽

São Paulo ◽

Air Humidity ◽

Relative Air Humidity ◽

The Impact ◽

Fourth Quartile

Abstract Santos is a seaboard Brazilian city recognized by its port activity where the road and rail infrastructure along with the large transportation operation, displays an important factor to contribute with all kinds of toxic and air pollutants. Recent studies have suggested associations between air pollution and various birth outcomes. Pollutant gases such as NOx, O3 and particulate matter PM2,5, PM10 have been cited as factors involved in such outcomes. The present study aims to assess the relationship between atmospheric pollutants and perinatal outcomes in the city of Santos from Jan. 2012 to Dec. 2015. Cross-sectional study that analyzed 10.319 singleton births in an area set with 2 km radius of the monitoring stations. Birth weight and information on mother and pregnancy were obtained at the Brazilian “Born Alive National Information System”. Daily records of air pollutants (PM10, PM2.5, NO2 and O3), temperature and relative air humidity, for the study period, were obtained from São Paulo State Environmental Agency (CETESB). Associations between preterm birth and air pollutants mean levels at each gestational trimester were investigated using multiple logistic regression model controlled by the variables: infant sex, type of delivery, maternal education. prenatal care, and number of previous live births, temperature and relative air humidity. NO2 e PM2,5 was not associated with preterm birth. O3 was significantly associated in the first trimester in the fourth quartile (OR = 1,47 CI 95% 1,05; 2,07). PM10 was significantly associated in the first trimester for the fourth quartile (OR = 1,28 CI 95% 1,00; 1,64), second trimester for the second quartile (OR = 1,37 CI 95% 1,07; 1,77). Conclusions the results shows evidence that maternal exposure to air pollution especially during the first trimester of pregnancy may contribute to preterm birth. Further actions are needed towards controlling air pollution are strongly recommended for promoting early-life health. Key messages This is the first research of this kind that was made in Santos. It brings important evidence of the impact in the life of the population, especially those whose is not even born yet. It can be used as a resource to guide public policies in health, especially the guidelines that dictate the concentration of air pollutants and air quality.

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