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548 CHAPTER 52 1962 Guide And Data Book capacity of the storage room and subtracting the space occu pied by the grapes, allowing K cu ft per lug. The space occu pied by 1 lb of sulfur dioxide at 32 F is 5.5 cu ft. Other methods of applying sulfur dioxide that are some times used are the placing of pads of sodium bisulfiite powder in the packages of grapes, or mixing sodium bisulfite with the sawdust. About 5 grams of the chemical are used for a lug of 20 lb of grapes. Sulfur dioxide fumigation must be done with caution to avoid injury to workers, fruit and equipment. Even a concen tration of 0.25 percent can cause respiratory spasms and death from asphyxiation if the victim cannot escape from the fumes. Concentrations as low as 0.04 percent are irritating and can injure the mucous membranes. A gas with can- nister for acid gases or goggles should be worn when working even in weak concentrations. On exposure to irritating con centrations, washing the mouth, eyes, and nose with water and applying a few drops of ephedrine sulfate in the nose gives relief. Because of the corrosive action of sulfur dioxide exposed metal surfaces in the storage rooms and brine spray chambers should be coated with acid-resistant paints. Fumigation with sulfur dioxide is suitable for California grapes only. American grape varieties and most other fruits and vegetables are seriously injured even by weak concentra tions of this gas. Care must be taken to prevent leakage of sulfur dioxide from grape rooms into rooms containing other fruits, vegetables, eggs, meat and poultry. Nitrogen Trichloride Gas Nitrogen trichloride fumigation of citrus to control decay has been practiced extensively in California. This gas is effec tive against blue and green mold and stem-end rot caused by Dipiodia natalensis. Nitrogen trichloride cannot be stored in cylinders because it is very unstable and is explosive in concentrated form. Therefore it must be generated where used by means of special equipment. The fruit may be treated in the storage room, coloring room, or refrigerator car. Oranges are treated with 6 to 14 mg per cu ft of air for 3 to 6 hr and lemons and grape fruit with 1 to 2 mg per cu ft for 4 hr once or twice weekly. Overtreatment may cause etching, pitting, and browning of the skin and should be avoided. Fumigation with nitrogen trichloride has been used with cantaloupes, tomatoes, and peppers but not as exten sively as with citrus. Cantaloupes are treated with 11 to 25 mg per cu ft for 3 to 5 hr to reduce spoilage. Post harvest losses of tomatoes may be reduced by fumigating for 4 hr on two consecutive days with 5 to 12 mg per cu ft. Overtreat ment causes sinking of the stem scar. Treatment of peppers is similar to that of tomatoes except that only 4 mg of nitrogen trichloride per cu ft is used. Higher concentrations causes bleaching of the stem. Ethylene Oxide Gas Ethylene oxide is used to reduce spoilage of high moisture content dried fruits such as figs, prunes and dates and to re duce the microbial content of dried spices. Dried fruit is treated by putting a mixture of liquid ethylene oxide and iso propyl formate in the center of the master carton and then seating the package. This mixture vaporizes readily and pene trates the smaller packages. A vacuum process is used in fumigating spices. ANTISEPTIC WASHES Many fruits and vegetables are washed before packing to remove dirt and improve appearance. In some ice water baths are used to remove the field heat- If the water is recircu. fated and used repeatedly, as is often done when water scarce or when it is refrigerated for hydrocooling, it may ^ come heavily contaminated with decay producing bacteria and fungi. Antiseptic materials that are nontoxic to human beings in concentrations used are added to the water to de stroy these germs and also to kill fungi and bacteria that are on the surface of the fruits and vegetables. Chlorine washes containing 50 to 100 ppm of chlorine are in extensive commercial use for fruits and vegetables, but there are very few actual data to show how effective they are in reducing decay. In some cases, the chlorine is used in the form of hypochlorite solutions and in other cases as chlora mines. This treatment is probably beneficial in reducing con tamination of the wash water, but much more research wfl] be required to determine its actual value and to perfect Borax. Borax washes have been used for many years to control green mold and stem-end rot of critus fruits. The fruit is dipped in a solution containing 5 to 8 percent borax held at a temperature of 100 to 110 F for 3 to 5 min and then rinsed to remove the excess borax. The treatment should be applied as soon as possible after harvest to obtain maximum benefit*7 .Sodium ortho-phenylphenate. Sodium ortho-phenylphenate has been substituted to a large extent for borax in treating Florida citrus fruit. It is quicker acting than borax, but is more apt to cause rind injury. The likelihood of injury can be reduced to a large extent by adding hexamine to the solution. The concentration of sodium ortho-phenylphenate should not exceed 1 to percent or be less than % percent. Hexamine at tiie rate of one part to two parts should be added to pre vent rind injury. Sodium ortho-phenylphenate also may be mixed with the wax emulsion and applied as a flood spray to the fruit. Sodium ortho-phenylphenate is also used in the Pacific Northwest as an antiseptic wash for apples and pears. A concentration of 0.6 percent in a buffered solution contain ing enough alkali to maintain a reaction of about pH 12 is used. The fruit is sprayed with the solution and then rinsed with fresh water. Chlartetracydine. Chlortetracycline, an antibiotic, is added to the cooling water in some poultry processing plants to re duce bacterial contamination and extend the shelf life. When used at a concentrationof 10 ppm the poultry remains in good condition for 14 to 21 days in commercial refrigeration. For best results it is important that high sanitary standards be maintained in the processing plants. TREATED FRUIT WRAPPERS, BOX UNERS, PAPER BAGS AND CARTONS Treated fruit wrappers of various kinds are used for the control of apple scald and decays of several kinds of fruits. Oil-impregnated paper wrappers are used for apple scald control. The wrappers contain about 15 percent (by weight) of tasteless odorless mineral oil. Shredded oiled paper dis tributed through the package at the rate of about J4 lb for each bushel of apples is nearly as effective as wrapping the fruits individually. Oiled paper does not entirely prevent scald. Some extremely susceptible varieties develop scald in spite of the oiled paper but to a lesser degree than when the paper is not used. Also susceptible varieties that are picked too immature or held in poorly ventilated common or cold storage during the critical 6 to 8 week period after harvest are benefited very little by oiled paper. Copper resin/ito-oil impregnated wrappers, containing about 1.5 percent basic copper and 17 percent mineral oil, are used to control both gray mold decay and scald on Anjou The oil controls scald and the copper prevents the gray fungus growing from infected fruit to adjacent sound fruit.0 _J Supplements to Refrigeration 549 Diphenyl impregnated paper wrappers, box liners, paper and cartons are used to control the blue and green molds god stem-end rot of citrus fruits. Diphenyl volatilizes slowly aod inhibits the development of decay. It does not kill the fungus, and the decay is apt bn develop after the wrappexs are removed or the fruit is taken from the treated packages. Diphenyl evaporates rapidly after fruit is unpacked and does not affect the odor or taste of citrus fruit. Since diphenyl isay cause undesirable flavors in other fruits and food prod ucts, packages of citrus fruit treated with it should be stored by themselves.*7 SULFUR DUST Dusting peaches with sulfurduring thegrading process aids in reducing losses from brown rot. The dust is frequently ap plied before defuzzing, but results of recent experiments indi cate that the treatment would be more effective if the dust were applied after defuzzing.70 IRRADIATION There has been much research in recent years on preserva tion of food by irradiation with cathode and gamma rays. This means of preservation of both canned and fresh foods has considerable promise but it is still in th3 experimental stage. Preservation by this means has not been entirely ac ceptable because treatments that are sufficient to kill micro organisms do not stop enzymatic activity and more intense treatments often injure the product. Also, undesirable flavors and odors are caused in some foods by irradiation treatments. There is a possibility of prolonging the storage life of foods in storage by using radiation exposures that only partially sterilize the food and would not cause undesirable changes in appearance, taste and odor.71-7*-7* MISCELLANEOUS TREATMENTS New treatments are continually being introduced, some of which have enough merit to become adopted commercially. Ices containing varous antiseptics such as bensoic acid and chloramine have been tried for different commodities, but have not been generally adopted. A large number of antiseptio washes and fumigants in addition to those already discussed have been tested and used for a limited time, but have been discarded because of injury to the food product, toxicity to human beings, or ineffectiveness in preventing spoilage. REFERENCES 1R. W. Bents, T. J. O'Grady, and S. B. Wright: Antioxidants awl food preservation (Food Technology, VoL 6, 1952, p. 302). 1 A. A. Klose, E. P. Mecchi, and H. L. Hanson: Use of anti oxidants in the frozen storage of turkeys (Food Technology, VoL 6, 1952, p. 308). * H. Iineweaver, J. D. Anderson, and H. L. Hanson: Effect of antioxidant on rancidity development in frozen creamed turkey (Food Technology, VoL 6, 1952, p. 1). 4 L. Jurd: Role of antioxidants (Diamond Walnut News, VoL 40 (2), 1958). ` Ora Smith: Sleeping potion chemical retards sprout growth * potatoes (Farm Research, New York State and Cornell Agri cultural Experiment Stations, VoL 12,1946, p. 15). * G. A. Johannessen and H. Oebker: New treatment promisee control of onion sprouting (Farm Research, New York State and Gomel! Agricultural Experiment Stations, VoL 17, 1951, p. 12). 7S. H. Wittwer, R. <5. Shann, L. E. Weller, and H. M. Sell: yhe effect of pre-harvest foliage sprays of certain growth regu lators on sprout inhibition and storage quality of carrots and onions (Plant Physiology, VoL 25, 1950, p, 539). . P. H. Heinze, P. C. Martin, and C. C. Craft: Further tests with 3-chtoro-isopropyi-N-phenyl carbamate as a sprout inhibitor . "^potato tubers (American Potato Jowned, VoL 32, 1955, p. R. L. Sawyer and S. L. Dallyn: Vaporized chemical inhibitors and irradiation, two new methods of sprout control for tuber and bulb crops {Proceedings, American Society for Horticultural * Science, VoL 67, 1956, p. 514). 10 W. G. Burton: Suppression of potato sprouting in buildings (Agriculture. VoL 65,1958, d. 299). 11L. C. Erickson: Lemon storage, prestorage treatment redaces black buttons, decay, delays fruit aging {California Agriculture, VoL 6,1952, p. 4). " W. 8. Ogilvy and J. C. Ayres: Postmortem changes in stored meats. II The effect of atmospheres containing carbon dioxide in prolonging the storage life of cut-up chicken (Food Technology 'Vol. 5,1951, p. 97). u W. S. Ogilvy: Storage of meat in carbon dioxide atmospheres at temperatures above freezing (Iowa State College Journal of Science, VoL 25 ,1951, p. 323). 14 A. A. Kraft ana J. C. Ayres: Post-mortem changes in stored meats. IV Effect of packaging materials on keeping quality of self-service meats (Food Technology, VoL 6, 1952, p. 8). " W. S. Ogilvy and J. C. Ayres: Post-mortem changes in stored meats. HI The effect of atmospheres containing carbon dioxide in prolonging the storage life of frankfurters (Food Technology,VoL 5,1951, p. 300). " W. S. Ogilvy and J. C. Ayres: Port-mortem changes in stored meats. V Effect of carbon dioxide on microbial growth on stored frankfurters and characteristics of some microorganisms isolated from them (Food Research, Voi-18,1953, p. 212). t7 T. Moran: Gas storage of meat and eggs (Food Industry, Vol. 3, 1938, p. 149). 10 W. A. Empey and W. J. Scott: Investigations on Chilled Beef, Part I, Microbial Contamination Acquired in the Meatworks (Australia Councilof Scientific and Industrial Research Bulletin No. 126, 1939). ** R. B. Haines: Tbe bacterial flora developing on stored lean meat, especially with regard to "slimy" meat (Journal of Hygiene, No. 33, 1933, p. 175). ** W. A. Empey and J. R. Vickery: The use of carbon dioxide in the storage of chilled beef (Aust/wo Council of Scientific and Industrial Research Journal, Vol. 6,1933, p. 233). " T. Moran, E. C. Smith, and R. G. Tomkins: The inhibition of mould growth on meat by carbon dioxide (Journal of Society <fChemical Industry, Vol. 51,1932, p. 114T). ** R. G. Tomkins: Mycology: The Inhibition of the Growth of Meat-Attacking Fungi by Carbon Dioxide (Department of Scien tific and Industrial Research, Food Investigations Board Repeat 1932, Great Britain, 1933, p. 48). J. Brooks: The effect of carbon dioxide on the color changes or bloom of lean meat (Journal of Society of Chemioal Industry, Vol. 62, 1933, p. 17T). 04 F. W. Tanner: The Microbiology of Foods (Garrard Press, Champaign, I1L, 1948, 4th ed). * E. H. Callow: Gas storage of pork and bacon, Part 1. Pre liminary experiments (Journal of Society of Chemical Industry, Vol. 51, 1932, d. 116T). * E. H. Callow: Gas Storage (Department of Scientific and In dustrial Research, Food Investigations Board Report 1932, Great Britain, 1933, p. 112). . 77 E. H. Callow: The Gas Storage of Bacon (Department of Scientific and Industrial Research, Food Investigations Board Report 1935,1936, p. 61). " F. P. Coyne: The effect of carbon dioxide on bacterial growth (Royal Society of London Proceedings, Series B, VoL 113, 1933, p. 196). ** M. E. Stansby and F. P. Griffith: Carbon dioxide in handling fish (Industrial and Engineering Chemistry, Vol. 27, 1935, p. 1452). ** T. Moran: Gas storage of meat and eggs (Food Industry, Vol. 9,1937, p. 705). a P. F. Sharp: Tbe pH of the 'white as an important factor influencing the keeping quality of hens' eggB (Science, Vol. 69, 1929, p. 278). ** P. F. Sharp: Preservation and storage of hens' eggs (Food Research, Vol. 2,1937, p. 477). P. F. Sharp and G. F. Stewart: Carbon dioxide and keeping quality of eggB (US Egg and Poultry Magazine, VoL 37, No. 67" 04 F. Kidd and C. West: Refrigerated Gas Storage of Apples (Food Investigations Board (Great Britain], Department of Scientific and Industrial Research Leaflet No. 9,1936). * R. M. Smock: Controlled-Atmosphere Storage of Apples (New York (Cornell] Agricultural Experiment Station Bulletin No. 759,1949). * I. J. Pflus: Oxygen Reduction in CA Storages: A Comparison