HORTSCIENCE 36(6):1091–1095. 2001. Quality and Microbial Changes of Fresh-cut Mango Cubes Held in Controlled Atmosphere Nithiya Rattanapanone 1 , Yuen Lee 2 , Tianxia Wu 3 , and Alley E. Watada 4 Horticultural Crops Quality Laboratory, Beltsville Agricultural Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, MD 20705 Additional index words. respiration, bacteria, yeast, shear, color, Mangifera indica Abstract. The marketable period of fresh-cut ‘Tommy Atkins’ and ‘Kent’ mango cubes was 3 to 5 days at 10 °C and 5 to 8 days at 5 °C. The marketable period was extended by 1 to 2 days when cubes were held in a 4 kPa O 2 + 10 kPa CO 2 or 2 kPa O 2 + 10 kPa CO 2 (balance N 2 ) atmospheres, depending on cultivar and temperature. Variations in texture (shear force), pH, and soluble solids were greater among cubes from different mango lots than among cubes held at different temperatures or atmospheres. Yeast count increased more with time than did the total mesophilic aerobic count, and the increase was less under controlled atmosphere (CA) than in air at 10 °C. The CA was beneficial in maintaining quality of the cubes; however, low temperature was more effective than CA. 35 d in an atmosphere of 6 kPa O 2 plus 10 kPa CO 2 at 8 °C (Bleinroth et al., 1977). Maekawa (1990) maintained ‘Irwin’ mangoes for 4 weeks at 12 °C in an ethylene-scrubbed at- mosphere of 5 kPa O 2 plus 5 kPa CO 2 . Bender et al. (1995) reported that unripe ‘Kent’ and ‘Tommy Atkins’ mangoes could be held for 21 d at 12 °C in 3 kPa O 2 plus 25 kPa CO 2 , and the fruit ripened after 5 d at 20 °C. Ripening of ‘Nam Dok Mai’ mangoes was delayed at 20 °C when O 2 was reduced from 19 kPa to 7 kPa (Yantarasri et al., 1995). ‘Manila’ and ‘Oro’ mangoes were not injured, but ripening was delayed, when held in 0.8 kPa O 2 and up to 60 kPa CO 2 for 160 min at 48 °C for insect disinfestation (Yahia et al., 1997). Controlled atmospheres extend shelf life by delaying ripening, but the quality of CA-stored man- goes is only marginally better than that of air- stored mangoes (Hatton and Reeder, 1967; Spalding and Reeder, 1974). Limbanyen et al. (1998) reported that 10 kPa O 2 plus 10 kPa CO 2 retarded decay and browning of fresh-cut ‘Tommy Atkins’, ‘Haden’, and ‘Palmer’ mangoes. They re- ported that mangoes should be ripe, have no green color, but not be over-ripe for use as a fresh-cut product. In our preliminary study, we found that ‘Tommy Atkins’ and ‘Kent’ mangoes should be between 13 to 27 N firm- ness (11.1-mm probe on a Magness-Taylor fruit firmness tester) to have an acceptable quality and reasonable shelf life as a fresh-cut product. The lower limit of acceptable O 2 level in packaged fresh-cut mangoes is un- known and needs to be identified for select- ing appropriate film for packaging. Addi- tionally, the effects of a combination of low O 2 with elevated CO 2 on quality changes of fresh-cut mangoes are unknown. This paper describes the respiration rates and changes in quality and microbial pop- ulation of fresh-cut ‘Kent’ and ‘Tommy Atkins’ mangoes held in 2 or 4 kPa O 2 , respectively, plus 10 kPa CO 2 (balance N 2 ) at 5 °C and 10 °C. The O 2 levels were slightly above the breakpoint of the respiratory quo- tient for the respective cultivars, as deter- mined in preliminary work. Materials and Methods ‘Tommy Atkins’ or ‘Kent’ mangoes, grown in Mexico, that were heat-treated for insect disinfestation, were purchased at the Maryland Wholesale center in Jessup, Md. They were held at 15 or 20 °C until most of the fruit had ripened. Selected ripe fruit were placed overnight at 5 °C , and on the follow- ing morning, they were washed with 5 °C water, dipped for 2 min in 5 °C 2.7 mM sodium hypochlorite solution (adjusted to pH 7 with citric acid) and allowed to air-dry. Firmness was measured in the middle of one side of the fruit with an 11.1 mm probe on a Magness-Taylor fruit firmness tester and only fruit having firmness within a 13 to 27 N range were used for the study. CA study with ‘Tommy Atkins’. Seventy- eight ‘Tommy Atkins’ fruit were separated into three replicates. Fruit were peeled and the flesh was removed from the seed. The flesh was sliced into 2-cm strips, which were then cut into 2 × 2-cm cubes and rinsed in 5 °C 1.9 mM sodium hypochlorite solution at pH 7 for 2 min. Each replicate was divided into 16 samples of ≈250 g each and placed on a plastic screen in a 2-L glass jar. Eight lots were placed at 5 and 10 °C each. The samples for CA treatment were flushed immediately with N 2 and CO 2 until the gas mixture reached 4 kPa O 2 and 10 kPa CO 2 . Subsequently, air or a gas mixture of 4 kPa O 2 plus 10 kPa CO 2 (balance N 2 ) was metered through the jars at a rate of 10 or 15 mL·min –1 at 5 or 10 °C, respectively. A jar of each replicate was re- moved on days 0, 3, 5, and 8 for quality and microbial analysis. Respiration rates were measured on samples held for 8 d. Oxygen uptake and CO 2 production were measured every 6 h with an automatic sam- pling system (model S-3A/I; Ametek oxygen analyzer; Ametek, Pittsburgh) using a model CP-3A carbon dioxide analyzer (Ametek). Quality attributes measured were visual quality, shear force, pH, soluble solids, color, and microbial population. Visual quality was scored using a scale of 9 = excellent, 7 = good, 5 = fair, 3 = poor, and 1 = inedible, based on discoloration and watersoaking of the mango cubes. Shear force of a 100 g sample was determined with a Kramer-Shear cell attached to a Texture Test System (Food Technology Corp., Rockville, Md.) as de- scribed elsewhere (Izumi and Watada, 1995). Color of cubes was based on CIE L*, a*, and b* values obtained with the model CR-300 Minolta Chromameter (Minolta Instrument Systems, Ramsey, N.J.), which was calibrated with a white tile. For microbial analysis, a 20- g sample of mango cubes was macerated in 40 mL of sterile peptone, pH 7.4, with a model 400 Lab Stomacher (Seward Medical, London, U.K.). A sample of each homoge- Received for publication 31 Mar. 2000. Accepted for publication 20 Nov. 2000. We thank Willard Douglas for excellent technical assistance. Use of company or product name by the U.S. Dept. of Agriculture does not imply approval or recommen- dation of the product to the exclusion of others which also may be suitable. The cost of publishing this paper was defrayed in part by the payment of page charges. Under postal regulation, this paper therefore must be hereby marked advertisement solely to indicate this fact. 1 Current address: Dept. of Food Science and Tech- nology, Faculty of Agro-industry, Chiang Mai Univ., Doi Come Campus, Chiang Mai, 50200 Thailand. 2 Current address: Dept. of Biological and Environ- mental Sciences, Univ. of District of Columbia, Washington, D.C. 3 Current address: Agronomy Dept., Nanjing Agri- cultural Univ., Peoples Republic of China. 4 To whom reprint requests should be addressed. E-mail address: yoal@earthlink.net Mangoes are delicious, but require peel- ing, removal of flesh from the seed, and slicing before consumption. Thus, the fruit might have greater appeal if they were peeled and sliced for immediate consumption. Very little is known about the potential shelf life, quality changes, or microbial population of fresh-cut mangoes. Whole ‘Irwin’ and ‘Tommy Atkins’ mango fruit can be stored for 3 weeks at 10 °C, whereas some cultivars, such as ‘Haden’ and ‘Keitt’, develop chilling injury symp- toms at this temperature (Hardenburg et al., 1986). Controlled atmosphere (CA) storage can be used to extend the shelf life, but the extension varies with temperature, atmo- sphere, and cultivar. ‘Alfonso’ mangoes can be kept satisfactorily for 35 d in 7.5 kPa CO 2 at 8.3 to 10 °C and ‘Raspuri’ for 49 d in 7.5 kPa CO 2 at 7.2 °C (Kapur et al., 1962). ‘Haden’ mangoes can be successfully stored for 30 d and ‘Carlota’, ‘Jasmin’, and ‘Sao Quirino’ for