Fourth Week Of Storage Research Articles

Influence of postharvest hot-dip fungicide treatments on Redblush grapefruit quality during long-term storage/Efecto de los tratamientos fungicidas postcosecha por inmersión en agua caliente sobre la calidad del pomelo Redblush durante el almacenamiento en frío

The efficacy of postharvest hot-dip treatment on Redblush grapefruit was investigated by 3-min dips in water at 50°C and 20°C, with and without 1500 ppm imazalil (IMZ) or thiabendazole (TBZ). Fruits were stored for 16 weeks in cold rooms at 8°C and then held at 20°C for 1 week to simulate shelf life. IMZ and TBZ treatment at 20°C considerably reduced the incidence of chilling injury (by about 50-60%) and the percentage (by 20%) of fungal infections. The effectiveness of the two fungicides was found to be considerably increased at 50°C. However, the beneficial effect of hot-dip treatment was noted, whether or not associated with the use of fungicides. The chilling index was threefold lower in fruit dipped in water at 50°C. Similar results were obtained by IMZ treatment and mold decay was decreased by about 50%. IMZ treatment at 50°C proved to be phytotoxic, thus resulting in reddish peel pitting, starting on the fourth week of storage. No further detrimental heat-related effect was detected in the remaining cases. Fruit treated with the two fungicides exhibited no significant differences in respiration rate under cold storage, when compared to control. By contrast, by the end of shelf life, sharply increased values were found in fruit treated with IMZ at 20°C. Endogenous ethylene production and internal quality attributes (juice%, total soluble solid content, juice acidity, and ripening index) did not reveal important differences between treatments. Ethanol concentration in the juice was remarkably lower in fruit treated with the two fungicides, whereas differences due to dip temperature were negligible in most cases.

Effects of Field Storage on Guayule Rubber Quantity and Quality

Abstract Irrigation treatments affected the amount of biomass produced, but not the NR percentage of the plant or the quality or quantity. Different guayule genotypes varied in their rate of rubber degradation over storage time. All lines tested in this experiment decreased in Mw by the end of the storage period, but degradation in some did not occur until the fourth week of storage. An increase in Mw of most lines was seen after the first week of storage, indicating that the enzymatic processes are still functioning beyond the first few hours of harvest, and for some lines, beyond the initial sample taken after one week of field storage. Other lines may follow this same pattern of degradation, but it was not detected by the sampling protocol in this study. Guayule lines 11605, 11619 and interspecific hybrid AZ101, when irrigated between 4 to 7 times per year (50 to 90 cm/year), harvested in early spring, and then stored in the field as whole plants for no more than 2 weeks, would yield optimum rubber quality and quantity (per acre) with little or no deterioration. Other lines in this study, 11604, N565, 593, and 11634, cannot be field stored for longer than 1 week without a loss of rubber quality and quantity based on these results. The variation seen in the different lines indicates two important points. First, the amount of time plants remain in the field following harvest is an important determinant of rubber quality and quantity. Secondly, selection for degradation characters should be possible for crop improvement.

Survival of Large Populations of Listeria monocytogenes on Chicken Breasts Processed Using Moist Heat

The ability of Listeria monocytogenes to survive and proliferate on chicken processed using a moist heating method was investigated. Chicken breasts were inoculated with 106–107 microorganisms/g, cooked to one of five different cooking temperatures, then either vacuum packaged or wrapped in an oxygen permeable film and stored at 4°C for up to 4 weeks or at 10°C for up to 10 d. Lethality was directly related to the cooking temperatures employed in this study, however survivors were encountered at each of the heat treatments employed. By the fourth week of storage at 4°C, the L. monocytogenes population in all of the samples, except those cooked to 82.2°C increased significantly. In contrast, within the first week of storage at 4°C the population increased in only three samples (73.9°C film overwrap, 65.6°C and 71.1°C vacuum packaged). Storage at 10°C allowed microbial populations in 6 of the 10 treatments to significantly increase within 3 d, with the remaining 4 significantly increasing within 10 d. Differences in packaging influenced the growth rate of L. monocytogenes at both storage temperatures.

Effect of Emulsion Characteristics of a Low-Fat Dairy Spread on Bacterial Growth

The bacteriological keeping quality of a low-fat dairy spread was investigated and found to be closely related to the size of the serum droplets dispersed in the continuous fat phase. Standard plate and psychrophilic bacterial counts on 38.8% fat spreads stored at 7.2C for four weeks increased by about one log cycle. The majority of the serum droplets were in the size range of 3 to 20 microns. In the 30.0% fat spreads, however, where many of the serum droplets exceeded 50 microns, the standard plate and psychrophilic bacterial counts increased by three to four log cycles over the four-week storage period.

Effect of Heat Treatment and Storage Temperature on Phosphatase Reactivation in Butter

Cream separated from Grade A raw milk was pasteurized at 77, 85, 93, and 101.7C using holding times of 15 seconds, 10, and 15 seconds, 5, 10, and 15 seconds, and 1, 5, 10, and 15 seconds, respectively. Butter churned from these creams was stored at 4.4 and 10C for 24 hours, one, two, and four weeks. Phosphatase tests on the butter were made immediately after churning and at the end of each storage period. Positive reactions were observed most frequently under the following conditions: Pasteurization at 93C for 10 seconds, 10C storage temperature, four-week storage period, and during the fall season (September–November). No positive reactions were obtained in the butter churned from cream pasteurized at 77C.