Volume 6, Spring 2008 - Saddleback College

Fall 2007 Biology 3A Abstracts
16. THE EFFECTS OF OZONE ON ESCHERICHIA COLI ON SPINACH LEAVES. Aaron Echols and
Crystine Gill*. Department of Biological Sciences, Saddleback College, Mission Viejo, California, 92692,
USA
Ozone treatment is an approved method of sanitation by the U.S. Food and Drug Administration.
Using an ozone method of sanitation would yield greater benefits to both consumer and the environment.
Although ozone is used as a disinfectant for various agricultural crops today, is not currently utilized to
sanitize spinach. It was predicted that E. coli contamination on spinach would be significantly reduced by
an aqueous ozone treatment. In this study, spinach was exposed to E. coli bacteria for twenty minutes.
One portion of the spinach was washed in ozonated water (oxidation reduction potential 500), and the
other portion was washed in untreated water, each for ten minutes. Samples of ozone-treated and waterwashed
contaminated spinach were plated and incubated for two days. A mean count of 104 E. coli cfu
per plate formed from the ozone-treated samples (n = 4, s.e. ± 5.7), and a mean count of 137 E. coli cfu
formed on plates of water-washed samples of spinach (n = 4, s.e. ± 16.2). The quantity of E. coli on the
spinach was reduced by the ozone treatment, although it was not found to be a significant reduction (one
tail t-test 0.11; P = 2.13).
17. THE EFFECT OF WAVELENGTH OF LIGHT ON THE DISCOLORATION OF WINE.
Greg M. Fitzgerald and Michael B. Zilly. Department of Biological Sciences, Saddleback College, Mission
Viejo, California, 92677, USA.
Wines are usually corked in bottles varying in different colors. The different colors of bottles are due to
help prevent light from entering the bottle, which discolors the wine. Since different wines are bottled in
different color bottles, it was predicted that the effects of wavelengths of light on two different types of
wine would discolor differently. A D’ Aquino Chianti and a La Loggia Barolo were obtained and
experimented on. The two wines were diluted and placed into test tubes, some covered with different
colors of cellophane. The test tubes were then placed in front of a full spectrum light for 14 days. Data
was analyzed from the points given from a Beckman Coulter DU 730 spectrophotometer. Mean values of
the two wines at blue light vs. mean values of the control showed p-values of p = 0.622 and p = 0.446 for
a two tailed t-test assuming unequal variance for the Barolo and Chianti, respectively. In conclusion, for
the time tested in this experiment, there is no significant difference between the discolorations of both
wines under full light to their control samples.
18. THE EFFECT OF APPLES ON THE RIPENING OF VALENCIA ORANGES (Citrus aurantium).
Monica Mehran and Paris Aliyazdi. Department of Biological Sciences, Saddleback College, Mission
Viejo, California, 92692, USA
Ethylene (C2H6) is a gaseous organic compound which can be thought of as a natural plant hormone,
produced in small amounts by most fruits and vegetables. To assess the significance of ethylene on fruit
ripening and maturation, we tested the effects of ethylene exposure on the Valencia orange (Citrus
aurantium), by using ripening apples, commonly known for producing significant amounts of ethylene gas.
The results of the experiment were consistent with the belief that the presence of ethylene accelerates
the ripening, or what is frequently referred to as “degreening” in citrus fruits such as oranges and
tangerines. There were very significant differences between the ripening time between the oranges that
were exposed to apples and those that were allowed to ripen without the presence of apples. The
ethylene released by the apples greatly reduces the time it takes for the orange to change color from
green to yellow to orange.
vi
Saddleback Journal of Biology
Spring 2008