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- Author or Editor: Dennis A Margosan x
Abstract
Early-season ‘Perlette’, ‘Cardinal’, ‘Flame Seedless’, and ‘Thompson Seedless’ table grapes (Vitis vinifera L.) were fumigated at 21°C with methyl bromide (MB) at 32 g m−3 for 3.5 hours, SO2 (0.5% for 0.5 hours), or the 2 fumigants in sequence. Quality evaluations were made following holding at 2.5° for 6 days and again after an additional 2 days at 21°. SO2 fumigation reduced the percentage of rotten berries and the combination of SO2 and MB reduced the amount of bunch rot (Rhizopus rot). SO2 slightly bleached the color of the dark-pigmented grapes. Bromine residues in MB-fumigated and untreated grapes averaged 10.8 and 1.4 ppm, respectively.
A new vapor phase hydrogen peroxide (VPHP) technology that uses relatively dry hydrogen peroxide pulses is a promising method for the disinfection of surface-borne bacteria, yeasts, and molds on walnut nutmeats. The number of colony forming units per gram (cfu/g) on untreated nutmeats was compared to those VPHP treated. Three culture media; dichloran rose bengal chloramphenicol agar base (DRBC, Oxoid), aerobic plate count agar (APC, Oxoid), and potato dextrose agar (PDA, Sigma), were utilized to evaluate cfu/g. Similar numbers of cfu/g of product were observed on APC and PDA. The more selective DRBC had lower cfu/g. Microorganisms washed from untreated walnut nutmeats purchased at retail outlets ranged between 17,000-29,000 cfu/g depending upon the culture medium used. The number of cfu/lg on nutmeats after VPHP treatments was reduced to 500-1400, a 95% reduction. VPHP may offer an alternative to propylene oxide fumigation. The moisture content of nutmeats was not significantly altered by VPHP. The Food and Drug Administration lists hydrogen peroxide as a “generally recognized as safe substance” (GRAS). Hydrogen peroxide is already produced in a food grade for aseptic packaging.