A commercial controlled delayed cooling or preconditioning treatment was developed to extend peach (Prunus persica) market life of the most popular California peach cultivars. A 24 to 48 h cooling delay at 68 °F (20.0 °C) was the most effective treatment for extending market life of internal breakdown susceptible peaches without causing fruit deterioration. This treatment increased minimum market life by up to 2 weeks in the cultivars tested. Weight loss and softening occurred during the controlled delayed cooling treatments, but did not reduce fruit quality. Detailed monitoring of these fruit quality changes during the delayed cooling period and proper use of fungicides is highly recommended for success in this new fruit delivery system. Rapid cooling after preconditioning is important to stop further fruit deterioration such as flesh softening, senescence, decay and weight loss. Controlled delayed cooling can also be used to pre-ripen susceptible and nonsusceptible peaches to deliver a ready-to-buy product to the consumer.
Carlos H. Crisosto, David Garner, Harry L. Andris, and Kevin R. Day
Joseph L. Smilanick, David Sorenson, Monir Mansour, Jonah Aieyabei, and Pilar Plaza
A brief (15 or 30 seconds) high-volume, low-pressure, hot-water drench at 68, 120, 130, 140, or 145 °F (20.0, 48.9, 54.4, 60.0, or 62.8 °C) was applied over rotating brushes to `Eureka' lemons (Citrus limon) and `Valencia' oranges (Citrus sinensis). The impact of this treatment on populations of surface microbes, injury to the fruit, the incidence of green mold (Penicillium digitatum)or sour rot (Geotrichum citri-aurantii), when inoculated into wounds one day prior to treatment, and temperatures required to kill the spores of these fungi and P. italicum suspended in hot water were determined. Fruit microbial populations were determined immediately after treatment. Decay and injuries were assessed after storage for 3 weeks at 55 °F (12.8 °C). The efficacy of the hot water treatments was compared to immersion of fruit in 3% wt/vol sodium carbonate at 95 °F (35.0 °C) for 30 seconds, a common commercial practice in California. Initial yeast and mold populations, initially log10 6.0 per fruit, were reduced to log10 3.3 on lemons and log10 4.2 on oranges by a 15-second treatment at 145 °F. Green mold control improved with increasing temperature and treatment duration. Green mold incidence was reduced from 97.9% and 98.0% on untreated lemons and oranges, respectively, to 14.5% and 9.4% by 30 seconds treatment with 145 °F water. However, immersion of lemons or oranges in 3% wt/vol sodium carbonate was superior and reduced green mold to 8.0% and 8.9%, respectively. Sour rot incidence on lemons averaged 84.3% after all water treatments, and was not significantly reduced, although arthrospores of G. citriaurantii died at lower water temperatures than spores of P. digitatum and P. italicum in in vitro tests. Sodium carbonate treatment for 30 seconds at 95 °F reduced sour rot to 36.7%. None of the treatments caused visible injuries to the fruit.
Krista C. Shellie
An instrumented sphere (IS) was used to identify high-impact areas on seven grapefruit (Citrus paradisi Macf.) packing lines in the Rio Grande Valley of Texas. The packing-line unit operations having the greatest percentage of high impacts were 1) the sizer, 2) when #2 fruit were separated by hand at the grading table, 3) when fruit were dumped from the harvest bin onto the packing line, and 4) when fruit dropped into a collection bin at the end of the packing line. The number of high impacts and the amount of cushioning in high-impact areas varied among the seven packing sheds. The amount of red dye visible on the surface of fruit collected from the end of each shed's packing line did not correspond with each shed's percentage of high impacts or with incidence of decay during fruit storage. The severity of impacts and degree of cushioning provided in these Texas packing sheds were comparable to that reported for 39 Florida packing houses. This study illustrates the usefulness of the IS for enhancing individual packing-line operations and for comparing individual shed performance to packing-line operations in other agricultural production regions.
Julio Loaiza and Marita Cantwell
Respiration rates of freshly harvested cilantro were moderately high (CO2 at 15 to 20 μL·g-1·h-1) and ethylene production rates were low (<0.2 nL·g-1·h-1) at 5 °C and were typical of green leafy tissues. Cilantro stored in darkness at a range of temperatures in air or controlled atmospheres was evaluated periodically for visual quality, decay, aroma, off-odor, color, and chlorophyll content. Cilantro stored in air at 0 °C had good visual quality for 18 to 22 days, while at 5 and 7.5 °C good quality was maintained for about 14 and 7 days, respectively. An atmosphere of air plus 5% or 9% CO2 extended the shelf-life of cilantro stored at 7.5 °C to about 14 days. Quality of cilantro stored in 3% O2plus CO2 was similar to that stored in air plus CO2. Atmospheres enriched with 9% to 10% CO2 caused dark lesions after 18 days; 20% CO2 caused severe injury after 7 days. Although visual quality could be maintained for up to 22 days, typical cilantro aroma decreased notably after 14 days, regardless of storage conditions.
James P. Mattheis
Washington State industry. Another impact of postharvest 1-MCP use is the potential to eliminate postharvest drench treatments for control of superficial scald and decay. Where the fungicide drench is not used, a renewed emphasis on field decay control
N.A. Mir and R.M. Beaudry
The changes in volatile-aroma of Penicillium expansium and Botrytis cinerea fungi and apple fruit inoculated with these fungi were studied using GC-MS. A specially designed chamber with raised end glass tubes with access ports fitted with Teflon-lined septa was used to determine the volatile profile for fungi on agar. Inoculated fruit were placed in glass flow-through chambers similarly fitted with sampling ports. Volatile collection from fruits or fungi was accomplished using solid phase micro-extraction (SPME) device (Supelco, Inc.). In fungi-inoculated fruits, volatiles not produced by uninfected fruit included formic acid, 2-cyano acetamide; 1-hydroxy-2-propanone, and 1-1-diethoxy-2-propanone, which were initially detected 6 hr after inoculation. These new volatiles are suggested to be synthesized specifically by the action of fungi on fruits as they were not detected from fungi that were grown on agar or bruised fruits. In general, esters, alcohols, aldehydes, ketones, acids, and hydrocarbons other than α-farnesene declined in fungi infected fruits.
W.R. Miller and R.E. McDonald
Solo-type papaya (Carica papaya L.) fruit at the mature green (MG) or one-quarter yellow (QY) stage of maturity were imported through the Port of Miami, Fla., and either irradiated (0.675 kGy) or not irradiated. Fruit condition and quality attributes were determined after ripening to the edible ripe stage at 25 °C before and after storage for 7 days at 10, 12, or 15 °C. The incidence and severity of peel scald was increased by irradiation regardless of storage and ripening regime; however, the degree of severity was dependent on fruit maturity at irradiation. Irradiated QY fruit tended to have the most serious incidence and severity of scald. Mature green fruit ripened at 25 °C without storage had the lowest incidence of fruit with hard areas in the pulp (“lumpy” fruit). The QY fruit generally were second only to irradiated MG fruit stored at 10 °C in incidence of lumpiness. Anthracnose sp. decay and stem-end-rots affected 53% of all fruit. The least decay occurred on fruit ripened at 25 °C without storage, regardless of fruit maturity, and the most decay occurred on QY fruit with or without irradiation. Fruit ripened at 25 °C without storage had more palatable pulp (5.5 N) at the edible ripe stage than did fruit held in storage and then ripened. The effect of fruit maturity or irradiation dose on fruit firmness, however, was dependent on the storage temperature. Mature green fruit ripened at 25 °C lost less weight than did those stored at cold temperatures prior to ripening. We recommend that importers obtain fruit with only a slight break in ground color, and distribute them as rapidly as possible, while maintaining transit/storage temperatures at or above 15 °C with or without exposure to irradiation.
K.S. Mayberry and T.K. Hartz
Trials were conducted in California to evaluate techniques to extend storage life of netted muskmelons (Cucumis melo L.). The use of polyethylene bags, either as individual melon wraps or as liners for 18-kg commercial cartons, minimized water loss and associated deterioration of the fruit. Individual bags and carton liners were equally effective. A 3-minute dip in 60C water effectively checked surface mold development on wrapped fruits. Lower temperature and/or shorter exposure treatments were less effective. When applied in addition to hot water treatment, imazalil fungicide did not confer significant additional benefit. The combination of polyethylene bags and hot water treatment maintained high quality, marketable fruit for at least 28 days of storage at 3C,
Harold E. Moline and James C. Locke
The antifungal properties of a hydrophobic neem (Azadirachta indica A. Juss.) seed extract (clarified neem oil) were tested against three postharvest apple (Malus domestica Borkh.) pathogens—Botrytis cinerea (pers.) ex Fr. (gray mold), Penicillium expansum Thom. (blue mold rot), and Glomerella cingulata (Ston.) Spauld. & Schrenk. (bitter rot). The antifungal activity of neem seed oil also was compared to that of CaCl2. A 2% aqueous emulsion of the clarified neem seed oil was moderately fungicidal to B. cinerea and G. cingulata in inoculated fruit, but bad little activity against P. expansum. Ethylene production was reduced 80% in fruit dipped in 2% neem seed oil compared to wounded, inoculated controls. Neem seed oil was as effective an antifungal agent as CaCl2, but the effects of the two combined were not additive.