Warm (20C) or cold (3C) broccoli florets (Brassica oleracea L., Italica Group) were sealed in bags of two types of nonperforated flexible polyvinylchloride film, TPM 87 or RMF 61, and kept at 5C for ...7 days. Temperature of the warm florets cooled to 5C in approximately 8 hours. Warm broccoli had 40% to 50% more CO2 and 25% to 30% less 02 than cold broccoli in packages of both film types 6 hours after seating. After 48 hours, however, concentrations of CO2 in bags of cold and warm broccoli had reached a steady state of approximately 14.5% in TPM 87 bags and 6% in RMF 61 bags. Concentrations of O2 were more variable. After 48 hours, O2 concentrations were approximately 2% to 4% in TPM 87 bags and 5% to 10% in RMF 61 bags. Initially, warm florets were rated lower for color, turgidity, and general appearance than initially cold ones after 7 days at 5C. Objectionable off-odors were formed from florets held in TPM 87 packages that had O2 concentrations of 1.5%
The potential use of vapor phase hydrogen peroxide (VPHP) to prevent decay caused by Botrytis cinerea Pers. ex Fr. in table grapes (Vitis vinifera L.) was investigated. 'Thompson Seedless' and 'Red ...Globe' grapes, inoculated with Botrytis cinerea spores, were placed in polyethylene bags and flushed for 10 minutes with VPHP generated from a 30% to 35% solution of liquid hydrogen peroxide at 40C. Immediately after treatment, bags were sealed and held at 10C. Vapor phase hydrogen peroxide significantly reduced the number of germinable Botrytis spores on grapes. The number of germinable spores on 'Thompson Seedless' and 'Red Globe' grapes had been reduced 81% and 62%, respectively, 24 hours following treatment. The incidence of decay on inoculated 'Thompson Seedless' and 'Red Globe' grapes was reduced 33% and 16%, respectively, after 8 days of storage at 10C compared with control fruit. Vapor phase hydrogen peroxide reduced the decay of noninoculated 'Thompson Seedless' and 'Red Globe' grapes 73% and 28%, respectively, after 12 days of storage at 10C. Treatment with VPHP did not affect grape color or soluble solids content
The tolerance of
Botrytis cinerea Pers. spores and Thompson Seedless grapes (
Vitis vinifera L.) to vapour phase hydrogen peroxide (H
2O
2 vapour) at various concentrations and temperatures was ...determined. The germination rate of botrytis spores decreased logarithmically with exposure time to H
2O
2 vapour. Treatments of 0.27 and 0.55 mg l
−1 H
2O
2 vapour at 20 or 30 °C, respectively, required 10.5 and 5.7 min to kill 99% of the spores. Grapes did not develop visible injury until they were exposed to 0.55 mg l
−1 H
2O
2 vapour for 6 h at 40 °C. Injury developed as a yellow-brown discoloration of the fruit and stems. Discoloration increased with time of exposure and concentration of H
2O
2 vapour. High treatment temperatures also increased the rate of discoloration. Prolonged exposure to H
2O
2 vapour caused increased water loss and loss of firmness of the grapes. Grapes were able to tolerate exposures of 0.27 mg l
−1 H
2O
2 vapour at 40 °C for 24 h with no visible injury. The difference in the tolerance of botrytis spores and grapes to H
2O
2 vapour may allow its use to control botrytis bunch rot in stored table grapes.
ABSTRACT
Honeydew muskmelons (Cucumis melo L.) were individually wrapped with polyvinyl chloride (PVC) shrink film and stored at 2.5° or 7.5 °C for 21 days and examined, then held an additional 2 or ...3 days at 20°C and examined again. Nonwrapped melons were the control. The concentration of CO2 in the cavity of wrapped melons stored 21 days was 5.6% at 2.5°C, 9.1% at 7.5°C, but only 1.1% and 1.5% in the nonwrapped held at 2.5°C or 7.5°C, respectively. Wrapped fruit ripened slower than nonwrapped fruit during storage and subsequent holding at 20°C, after which time 70% of the wrapped melons were rated eating ripe, but 62% of the controls were overripe. Wrapped melons exhibited 30% less chilling injury (CI) symptoms than nonwrapped fruit stored at 2.5°C. The CI symptoms ranged from reddish‐brown to dark‐brown surface discolorations and sometimes included dry sunken areas of skin. Fresh weight loss was about 1 % in wrapped melons, but 5% in nonwrapped fruit, regardless of storage temperature. Decay incidence was about equal in wrapped and nonwrapped melons after storage at 2.5°C, but was greater for wrapped than nonwrapped melons after storage at 7.5°C. Soluble solids content was about 12.5% in wrapped and nonwrapped melons stored at either temperature.
ABSTRACT
Fresh peaches (Prunus persica) were overwrapped in trays with 1 of 3 formulations of flexible polyvinyl chloride (PVC) film that differed in gas transmission rate or they were held in ...nonwrapped trays (controls). The CO2 transmission rate at 0°C for PVC type III film was 280 mL/m2. h (1 atmos); that of type II was 4 times greater and that of type I, about 5 times greater. The peaches were stored either 14 days at 0° or 7.5°C, or 7 days each at 0° and 7.5°C plus 2 days at 20°C to simulate retail display. The mean CO2 levels were 10, 7.2 and 4.7% in packages that were wrapped with PVC III film and held at 7.5°, 0°/7.5° and 0°C, respectively. CO2 in packages wrapped with PVC I or II was below 3% at each storage temperature. O2 concentration remained about 4% in all packages. Weight loss was less and fruit was firmer among those packaged in PVC III than among nonwrapped controls at each of the 3 storage temperatures. Storage temperature had no effect on weight loss or of fruit held in PVC III film. External appearance of fruit packaged with the 3 types of film was significantly better than that of the controls. Internal appearance of the peaches was unaffected by any of the treatments. A microatmosphere favorable for fresh peaches can be maintained within packages overwrapped with polymer films that are selectively permeable to respiratory gases.
California shipped approximately 18 million boxes of fresh peaches and nectarines in 1975. Seven test shipments were conducted in 1975 to determine if fruit could be shipped successfully in ...fiberboard boxes with net weights of 35 instead of 25 pounds. We also compared the relative advantages of Bliss-style and tray-style design corrugated fiberboard boxes. During 40 hours of transit, peaches averaged 54° F (12° C) in 25- and 35-pound fiberboard boxes. Nectarines averaged 48° (9° C) in the 25- and 35-pound fiberboard boxes during 96 hours of transit. However, these temperatures were higher than recommended for fruit shipments. All containers were in good condition on arrival, and no significant difference in fruit quality was detected between the fruit packed in the 25-pound fiberboard box or that packed in the 35-pound fiberboard box. About $1.5 million a year could be saved by using 35- instead of 25-pound corrugated fiberboard boxes for peaches or nectarines.
Excerpts from the report: Western iceberg lettuce accounts for approximately 20 percent of all carlots of fresh fruits and vegetables shipped from California, constituting the largest volume of a ...single perishable commodity shipped out of State. Lettuce shipments have increased by approximately 17 percent between 1968 and 1972. ARS agricultural engineers have developed a mechanical lettuce harvester, which may be the key element of a handling and marketing system that will enable producers and marketers of lettuce to keep pace with increasing costs. The purpose of this study was to determine if lettuce could be handled in large containers, and the effect of this handling on lettuce quality. A system to increase the product flow from the harvester into a shipping container was investigated. This system was based on jumble filling the lettuce into relatively large containers on the harvester. The containers varied in size, holding from 50 to 240 heads, compared with the present 24-head carton.
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