Maintenance Of Relative Humidity Research Articles

Effect of relative humidity on the quality and safety of peeled almond kernels (Prunus dulcis Mill.) during simulated maritime transport/storage.

Long-term transport and storage of peeled almonds under unsuitable conditions may cause the product's rejection. To get knowledge in this topic, peeled almonds were stored at 25°C and 60, 70, and 80% relative humidity (RH). The maintenance of high RH (80%) caused some visual defects after 4 months. Even though the 60, 70, and 80% RH did not clearly affect the production of primary and secondary products formed in the lipid oxidation during the 6 months of storage, sometimes an increase in the values of the specific extinction at the wavelength of 268nm (K268 ) was observed at 80% RH, suggesting the occurrence to some extent of secondary oxidation. Concerning microbial counts, the almonds stored at 60 and 70% RH presented a satisfactory microbial quality until 6 months; however, at 80% RH, the mold counts were higher than the reference values after 2 months. Several mycotoxins were detected at low levels, including aflatoxins B1 and G1, although some showed higher amounts at 80% RH. In general, it is recommended that almond producers and industrials should consider the use of low RH (<80%) for maritime transport and long-term storage of almond kernels. PRACTICAL APPLICATION: High levels of relative humidity during storage/transport of almond kernels favor fungal growth, mycotoxin production, and secondary oxidation (rancidity). It is recommended to keep the almond kernels under low RH(<80%) in maritime transport and long storage, especially in tropical countries.

Short postharvest storage under low relative humidity improves quality and shelf life of minimally processed baby spinach (Spinacia oleracea L.)

The maintenance of relative humidity (RH) after harvest is not always possible and can influence the quality of the raw material for minimal processing. The objective of this study was to evaluate if short-term postharvest exposure to different RH conditions such as high (99%), medium (85%) and low (72%) influenced the quality and shelf life of minimally processed baby spinach. Weight loss, water content (WC), osmotic potential, electrolyte leakage, headspace gas composition, sensory evaluation, colour, texture and microbiological populations were evaluated before and after processing, as well as during shelf life. Baby spinach exposed to low RH conditions on the one hand significantly showed lower water content and higher osmotic potential and stiffness after exposure for 36h at 15°C when compared to high RH conditions. After processing, samples exposed to low RH were rehydrated and no differences in dehydration were observed among samples exposed to different RH conditions. However, the percentage of damaged leaves increased significantly from 7.5% to 12.5% due to the process, this percentage particularly increasing with increasing RH. On the other hand, processed baby spinach exposed to high RH had a higher respiration rate, higher percentage of leaf damage, and increased electrolyte leakage, causing a decrease in quality resulting in a shelf life 4d shorter than baby spinach exposed to low RH. The observed changes were mainly linked to a significant postharvest breakage, which influenced the susceptibility to microbial colonization. Psychrophilic bacteria and Pseudomonas counts of samples exposed to high RH were 1log higher than those exposed to low and medium RH. To minimize the impact of leaf damage, baby spinach should be processed at medium–low hydration levels. This study shows that controlled RH after harvest is critical as it can influence the microbiological population and the maintenance of acceptable visual quality.

Assessment of Temperature and Humidity in Operating Room, Recovery Room and Intensive Care Unit

It is recognized that there may be numerous medical hazards associated with the maintenance of relative humidity below 50 percent. These include the danger of producing hypothermia in patients, especially during long operative procedures; the fact that floating particulate matter increased in conditions of low relative humidity, and the fact that the incidence of wound infections is minimized following procedures performed in those operating rooms in which the relative humidity is maintained at the level of 50 to 55 percent. So, we have checked room temperature and relative humidity of operating theater in Hanyang University Hospital during 1 year from January, 1991. The results were as following; 1) Room temperature wae maintained at the level of 23.6±0.8 to 27.7±1.3。C, and it was somewhat lower in shadowy rooms than in sunny ones. 2) Relative humidity was highest level in July, and it was maintaiaed at the level of 41.7±4.9 to 47.0±7.7%. Generally, it was decreased unsignificantly in order of ICU, recovery room, newbuilt shadowy rooms, old shadowy rooms, and sunny rooms. 3) Relative humidity was significantly decreased to 2.4±3.8-28.9±5.0% in spring, autumn, and winter. 4) Absolute humidity was maintained at the level of 11.6±1.7 mgH₂O/L in summer, and l.l±1.4 mgH₂O/L in winter. With above results, we recognized that room temperature of operating theater was maintained at the level of recommending degree, but relative humidity(percent) was too low to be suitable for operation and/or special patient care. This means that ventilation of operating theatre should be installed with proper temperature and relative humidity controlled units.

Temperature and plant responses to paper and plastic protectors on cantaloupes

Abstract does not appear. First page follows. Introduction When warm-season plants are grown during the winter months, some means of microclimatic manipulation becomes essential. This is the case in the production of cantaloupes in the desert areas of the south, vestern United States. At EI Centro in Imperial Valley, for instance, the average maximum in January of 1959 was 73.3° and the average minimum was 39.8° F. The soil temperature varies from a maximum of about 75° to a minimum of about 45° F. According to (Knott (1957)),5 the optimum temperature for cantaloupe growth is a monthly average of 90° during the day and 60° during the night. The optimum soil germination temperature is about 90° F. It is obvious, then, that conditions existing in this area during January are far from ideal for the germination and growth of cantaloupe plants. In contrast to the use of plant protectors in many other areas of the country, those used during the winter season in the desert areas of California remain in place for as long as three months. Cantaloupes planted during December remain under the protection of the shelters for nearly half of their life span. Any device employed under such conditions must meet certain requirements in order to be of value. Conditions should be such that rapid growth occurs and vigorous and hardy plants are produced. Environmental modifications which would create conditions for the plants more ideal than those naturally occurring would be: increased daytime air temperature, but not in excess; maximum increase in nighttime air temperature, hence protection from frost; increase in soil temperature; and maintenance of relative humidity at moderate levels. In addition to the conditions which relate directly to plant growth, shelters must also provide protection from wind and blowing sand.