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Traditionally the people of India have a long-standing practice of using wide variety of herbal products in treatment of diseases or as preservatives in foods. Spices are indispensable components of Indian cuisines since ancient times. Spices are considered as rich source of bio-active antimicrobial compounds. This study was undertaken to determine the in vitro antimicrobial activity of commercial essential oil of cinnamon (spice) and its main component for potential application in sprouts for reduction of microbial contamination. The antibacterial effect against Escherichia coli was tested using paper disk diffusion method, followed by determination of minimum inhibitory (MIC) and bactericidal (MBC) concentrations. Cinnamon essential oil exhibits antimicrobial activity against tested bacteria. The essential oil of cinnamon showed strong antimicrobial activity with MIC e" 1000ìl/ML and MBC e′4000ìl/ML. The resultssuggest that the activity of the essential oil of cinnamon can be attributed to the existence mostly of cinnamaldehyde which appear to possess similar activities against thetested bacteria. This material could be served as an important natural alternativeto prevent bacterial growth in food products.
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BIOSCIENCES BIOTECHNOLOGY RESEARCH ASIA, June 2016. Vol. 13(2), 1183-1188
* To whom all correspondence should be addressed.
E-mail: ketu8938@gmail.com
Cinnamon Oil as a Antimicrobial Agent to Reduce E.coli
Contamination in Sprouts and its Effect on Quality Parameters
Ketaki Patil and S Sasikala
Department of Food Process Engineering,
SRM University, Kattankulathur, 603-203, Tamil Nadu, India.
http://dx.doi.org/10.13005/bbra/2150
(Received: 11 April 2016; accepted: 09 May 2016)
Traditionally the people of India have a long-standing practice of using wide
variety of herbal products in treatment of diseases or as preservatives in foods. Spices are
indispensable components of Indian cuisines since ancient times. Spices are considered
as rich source of bio-active antimicrobial compounds. This study was undertaken to
determine the in vitro antimicrobial activity of commercial essential oil of cinnamon
(spice) and its main component for potential application in sprouts for reduction of
microbial contamination. The antibacterial effect against Escherichia coli was tested
using paper disk diffusion method, followed by determinationof minimum inhibitory
(MIC) and bactericidal (MBC) concentrations. Cinnamon essential oil exhibits
antimicrobial activity against tested bacteria. The essential oil of cinnamon showed
strong antimicrobial activity with MIC e” 1000ìl/ML andMBC e”4000ìl/ML.The
resultssuggest that the activity of the essential oilof cinnamon can be attributed to the
existence mostly of cinnamaldehyde which appear to possess similar activities against
thetested bacteria. This material could be served as an important natural alternativeto
prevent bacterial growth in food products.
Keywords: Spices; Antimicrobial; Bactericidal, essential oil, food safety.
Pathogenic and food spoilage bacteria
have been considered as the primary causes of
food-borne diseases and food quality deterioration
in both developed and developing countries. In
order to assure the food safety and to extend the
shelf life of food products, additions of chemical
preservative agents into food products or
decontamination treatments via physical, chemical
or biological process or their combinations have
been widely applied in food industries [1]. Essential
oils (EOs) can be extracted from various aromatic
plants including herbs and spices as they are
synthesized by these plants[2]. Spices and their EOs
have beenused as natural preservatives, to produce
wholesome food products, for extension of shelf-
life and toreduce pathogenic bacteria [3]. Cinnamon
belongs to the Lauraceae family and the genus of
Cinnamomum which comprises of about 250
species. Cinnamon is also a traditional herbal
medicine that is widely distributed in China, India
and Australia[4]. It has been applied in food,
seasonings, cosmetics and medical industries
because of its antimicrobial, antioxidant and anti-
carcinogenic activities. The antimicrobial activity
of cinnamon EO and its major composition had been
previously evaluated .Our study aimed to
investigate the antibacterial effect of cinnamon EO
by incorporating in the sprouts to provide safety
to consumer and better understanding on the use
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of natural antibacterial agents[5].Sprouts present a
unique food safety challenge compared to other
fresh produce, as the sprouting process provides
optimal conditions for the growth and proliferation
of pathogenic bacteria. The sprout industry,
regulatory agencies, and the academic community
have been collaborating to improve the
microbiological safety of raw sprouts, including
the implementation of Good Manufacturing
Practices (GMP), establishing guidelines for safe
sprout production, and chemical disinfection of
seed prior to sprouting. However, guidelines and
best practices are only as good as their
implementation [6]. The consumption of raw sprouts
is considered high-risk, especially for young,
elderly and immuno-compromised persons. By
considering this all outbreaks we can conclude
that there are lots of helpful ingredients and
chemical which will reduce the microbial
contamination. Addition of natural antibacterial
agent to sprouts will help to eliminate the
contamination to acceptable level. To reduce such
risk at beginning level is difficult task, and to
maintain the physical appearance and organoleptic
properties also, so use of natural antibacterial agent
will help to reduce contamination and will not
deteriorate its physical appearance and
organoleptic findings also[7].
MATERIALS AND METHODS
Green gram sprouts
Green gram seeds were purchased from
local super market, Potheri, Chennai, India Bacteria
and Culture Conditions
E.coli used in this study was isolated from
different water samples.
Essential oil
Cinnamon oil was purchased from local
shop in Chennai, India
Antibacterial assay
The antibacterial activity of
Cinnamonaldehyde was evaluated by disc diffusion
method. The exponential phase cultures of E.coli
were adjusted to the concentration of 1.02×108 CFU/
ml and were swabbed on Mueller Hinton
Agar(MHA) plates. Sterile paper discs (6mm
diameter) were loaded with 20ìl of different of
Cinnamonaldehyde, Sterile antibiotic discs were
placed on MH agar and incubated at 37°C for
overnight. Zone of clearance surrounding the discs
was measured using a transparent ruler and the
diameter was recorded in mm. Tween 80 was used
as control. Values are described as mean ± SD of
assays performed in triplicate
Minimum inhibitory concentration (MIC) and
minimum bactericide concentration (MBC)
The minimum inhibitory concentration
(MIC) and minimal bactericidal concentration
(MBC) was measured by broth dilution method
using Mueller Hinton Broth (MHB).Overnight
broth cultures of E.coli were adjusted. 20ìl of
different concentrations of Cinnamonaldehyde was
placed in sterilized test tubes to which contain 100ìl
of overnight cultured broth. The tubes were
incubated at 37°C for 18–24 h and OD600 values of
the cultures were measured, and the lowest
concentration that inhibited the bacterial growth
was taken as the MIC; the determinations were
performed in triplicates. All the MIC tubes (100ìlof
culture from each tube) were then used for
spreading on Muller Hinton Agar plates for colony
counting. The concentration at which no growth
was observed was determined as minimal
bactericidal concentration (MBC).
Total plate count
The total plate count TPC (aerobic,
mesophilic organisms) defines how many aerobic
(oxygen-loving), mesophilic (moderate-
temperature-loving) micro-organism colonies such
as bacteria, yeast and mould fungi will grow in 72
hours on an agar plate that was normed for
microbiological testing at a controlled temperature
of 30°C.The sample is disintegrated in a standard
diluent. The fibre suspension is transferred and
incubated. After the incubation time, the numbers
of bacterial colonies are counted on the respective
plates. The results are expressed separately as the
total colony number per gram dry mass of the
sample.
Determination of fat and protein content
Analyses of protein, fat, were performed
for three replicates. Methods used for the
estimation were AOAC standard methods [28].
Color Analysis of Sprouts
The colour parameter of sprouts was
monitored by Hunter L*, a* and b* values using
Hunter Colorimeter. L* (lightness), a* (redness)
and b* (yellowness) values were measured for
sprouts in three replicates.
1185
Preparation of sprouts
Green gram seeds were purchased from
local super market;sprouts were prepared at home
at ambient temperature by soaking seeds in three
times of water of its seed weight and soaked it for
6-8 hours. Though seeds were small in size it will
take less time for soaking. After the proper soaking
of seeds, water was drained from seeds. The
drained seeds were kept in muslin cloth or sieve
and covered using cloth for proper germination
for 10-12hrs. Actually germination procedure varies
with climatic conditions, as project was undertaken
in Chennai due to humid climate seeds were
sprouted in open climate without covering it with
cloth as it was growing sticky and sour. Then
sprouts were kept in water containing cinnamon
essential oil prior to using for decontamination.
Sensory Analysis
The sensory analysis for various samples
was conducted for taste, aroma, texture and
appearance. The sensory evaluations were
conducted on nine point hedonic scale. The
panelists were asked to rate the acceptability of
the product on a scale of 9 points ranging from 9 to
be “like extremely” to 1 to be “dislike extremely”.
Sensory was carried out in between semi
trained and untrained people for acceptability of
product.
RESULT AND DISCUSSION
Isolation of E.coli from water samples
Escherichia coli contamination of water
has emerged as an important public health concern.
Drinking and recreational waters have been linked
to human cases of disease Furthermore, E. coli
can be present in every water source which can
causes human illness, so E.coli was isolated from
drinking water source which was used for
germination of seeds, where total plate count was
found for E.coli was 9.2 x 108 CFU.
Antimicrobial assay
Antimicrobial assay was carried out by
Disk diffusion method to find out zone of inhibition
diameter for cinnamon essential oil purchased from
market.
Table 1. Antibacterial assay
Antimicrobial Micro- Concentration Zone of
agent organism inhibition
(mm)
E. coli Cinnamon 1% 24± 0.8
essential oil 1.8% 25± 0.8
2.55 27± 0.8
3.5% 29± 0.8
4% 32± 0.8
Tabl 2. Different parameters of germination
Sample Temperature Seed Amount Time Wt. Time Wt.
weight of water for after for after
soaking soaking germination germination
Green gram 25°C 50g 150ml 6-8hr 80g 8-10hrs 110g
Tabl 3. Total plate count of sprouts of 24 hours
Conc. Antibacterial effect
Colony count
0hr 1hr 2hr 4hr 8hr 12hr 24hr
Control 6.5 6.5 6.5 6.5 7.1 7.5 8.5
1% 6.5 6.5 6.3 6.1 5.9 5.9 5.9
1.8% 6.5 6.5 6.2 5.9 5.7 5.7 5.7
2.5% 6.5 6.5 6.1 5.7 5.6 5.5 5.4
3.5% 6.5 5.8 5.5 5.3 5.3 5.2 5.2
4% 6.5 5.4 4.9 4.7 4.7. 4.7 4.7
Table 4. Biochemical and nutritional analysis of
control samples (green gram sprout)
Control Days
Content 0th 1st 2nd 3rd
Protein (g) 4333
Fat (g) 0.6 0.4 0.3 0.2
1186
Table 5. Biochemical And Nutritional Analysis
Of Sample Containing Cinnamon Oil
Sample Containing Days
Cinnamon Oil
Protein(g) 4333
Fat (g) 0.6 0.4 0.3 0.2
Table 6. Color Analysis Of Green Gram
Sprouts After Addition Of Antibacterial
Agents
Sample L* a* b*
Standard 56.64 -21.69 11.05
Control 55.33 -20.32 17.93
1% 54.85 -20.16 18.41
1.8% 53.42 -20.12 17.69
2.5% 53.09 -20.09 19.46
3.5% 52.15 -19.45 17.08
4% 53.69 -19.56 19.13
Table 7. Sensory Evaluation
Attributes Samples
Control Samples
Taste 9 8.5
Colour 9 8.5
Texture 9 8.5
Appearance 9 8.5
Aroma 9 8.5
Overall Acceptability 9 8.5
Fig. 1. Total plate count reduction in sprouts after
incorporation of antibacterial agents Fig. 2. Sensory analysis diagram
Germination of green gram
Sprouting is the practice of germinating
seeds to be eaten raw or cooked. Sprouts can be
germinated at home or produced industrially. They
are a prominent ingredient of the raw food diet,
some parameters to be maintained while
germination.
Effect of Antibacterial agent on sprouts after
incorporation of essential oil
Cinnamon essential oil was incorporated
in water which used by mixing it with tween 80 for
reduction of E.coli contamination as pretreatment
for soaking of sprouts and Antibacterial effect
study was carried out by doing total plate count
after some hours interval.
Effect of antibacterial agent on Biochemical and
nutritional content of sprouts
Green gram seeds purchased from market
and sprouted and analyzed for protein and fat
which shows 3.2g, 0.2g protein and fat respectively,
Non significance was observed in content of
sprouts after addition of antibacterial agent than
control samples.
Color analysis of green gram sprouts by hunter
colorimeter
The values of color analysis of green gram
sprouts after addition of antibacterial agent showed
that it has the same color as like control. It shows
there is no significant color difference between
control and cinnamon oil containing samples.
Sensory analysis
Sensory evaluation was carried out using
9 point hedonic scale. The product was optimized
based on sensory analysis with acceptable score
8.5. The test samples were reasonably acceptable
1187
.Sensory analysis of the control sample and the
test samples (sprouts pre treated with
cinnamon(EO) essential oil) was conducted. The
test sample sprouts contained 1%, 1.8%, 2.5%, 3.5%
,4% EO water for pretreatment respectively.
Subjects were asked to sample the sprouts and
scores were given based on taste, texture,
appearance, aroma and overall acceptability.The
sensory analysis result showed that the samples
which treated with 2.5% of Cinnamon oil among
the other oil incorporated sprouts scored more on
the analysis. The overall acceptability of the
samples containing 2.5% oil was considerably
higher than the other test samples and the control.
CONCLUSION
Sprout is the intermediate stage between
the seed and plant containing cotyledon having
great kind of nutritional contents. It is said that
sprouts ‘represent the miracle of birth’. They are
in the true sense, super foods. They are alkaline,
whole, pure, and natural foods. It is inexcusable
that though aware of their miraculous effects,
sprouts are usually consumed in raw and cooked
form, and which cause the chances of human
illness due to presence of E.coli which came from
water source used for germination of seeds. Aim
of this project is that to reduce the contamination
level to the acceptable level by giving pretreatment
of natural antibacterial agent i.e. Cinnamon essential
oil. Sprouts are the protein rich products which are
used as energy boost, which gives proper nutrition
to human and that nutrition was not affected by
cinnamon essential oil, so this project indicates
that contamination of microorganism can be
reduced by some natural potential agents and that
not cause any significant effect on quality
parameters of sprouts.
ACKNOWLEDGEMENT
The authors are thankful to the Dr. K.A.
Athmaselvi, HOD, Food Process Engineering
Department and the Dr. M. Vairamani, Dean, School
of Bioengineering, SRM University, for providing
necessary facilities and continuous support to
carry out the research work
REFERENCES
1. Brul S, Coote P. Preservative agents in foods:
mode of action and microbial resistance
mechanisms. Int. J. Food Microbiol. 1999; 50:1–
17
2. M.M. Tajkarimi, S.A. Ibrahim Antimicrobial herb
and spice compounds in food, Food
Microbiology and Biotechnology Laboratory,
North Carolina A&T State University, 171-B
Carver Hall, Greensboro, NC 27411-1064, USA
3. Sara Burt* Essential oils: their antibacterial
properties and potential applications in foods
by Department of Public Health and Food
Safety, Faculty of Veterinary Medicine,
University of Utrecht, P.O. Box 80175, 3508
TD Utrecht, The Netherlands
4. Jayaprakasha, G.k. and Jagan Mohan Rao, L,
Chemistry , Biogenesis and Biological Activities
of Cinnamomum Zeylanicum. Critical Review
in Food Science and Nutrition, 2011; 5.pp 547-
562
5. Akbas MY, Olmez H ,Inactivation of Escherichia
coli and Listeria monocytogenes on iceberg
lettuce by dip wash treatments with organic acids
2007; 44(6):619-24.
6. G, Patil U, Chavan J K, Kadam S S, Salunkhe D
K. 1993. ”Effects of dry heat treatments to
peanut kernels on the functional properties of
the defatted meal.” Plant foods for human
nutrition (Dordrecht, Netherlands) 43(2): 157-
62.
7. K. Pandima Devi”, S. Arif Nisha, Sakthivel, S.
Karutha Pandian R. Eugenol (an essential oil of
clove) acts as an antibacterial agent against
Salmonella typhiby disrupting the cellular
membrane Department of Biotechnology,
Alagappa University, K.araikudi 630 003, Tamil
Nadu, India
8. Stelios Viazis, Mastura Akhtar, Joellen Feirtag,
Francisco Diez-Gonzalez* Reduction of
Escherichia coli O157:H7 viability on leafy green
vegetables by treatment with a bacteriophage
mixture and trans-cinnamaldehyde Department
of Food Science and Nutrition, University of
Minnesota, 1334 Eckles Ave. St. Paul, MN
55108, USA
9. G. A. Ayoola1*, F. M. Lawore1, T. Adelowotan2,
I. E. Aibinu2, E. Adenipekun2, H. A. B. Coker1
and T. O. Odugbemi Chemical analysis and
antimicrobial activity of the essential oil of
Syzigium aromaticum (clove) Depatment of
Medical Microbiology and Parasitology, College
of Medicine, University of Lagos, Lagos,
Nigeria.
1188
10. Jeongmok Kim, Maurice R. Marshall, and Cheng-
i Wei * Antibacterial Activity of Some Essential
Oil Components against Five Foodborne
Pathogens Food Science and Human Nutrition
Department, University of Florida, Gainesville,
Florida 3261 1-0370.
11. National Advisory Committee on Microbial
Criteria for Foods (NACMCF). Food and Drug
Administration., Microbiological safety
evaluations and recommendations on sprouted
seeds. International Journal of Food
Microbiology, 1999; 52, pp. 123-153
12. Patterson, J.E., Woodburn, M.J. Klebsiella and
other bacteria on alfalfa and bean sprouts at the
retail level. Journal of Food Science, 45, pp.
492-495 Peñas, E., Gómez, R., Frías, J., Vidal-
Valverde, C., 2008, Application of high pressure
treatment on alfalfa (Medicago sativa) and mung
bean (Vigna radiata) seeds to enhance the
microbial safety of their sprouts. Food Control,
1980; 19, pp. 698-705
13. Piernas, V., Guiraud, J.P., Disinfection of rice
seeds prior to sprouting. Journal of Food Science,
1997; 62, pp. 611-615
14. Prokopowich, D., Blank, G., Microbiological
evaluation of vegetable sprouts and seeds.
Journal of Food Protection, 1991; 54, pp. 560-
562
15. Randazzo, C.L., Scifò, G.O., Tomaselli, F.,
Caggia, C., Polyphasic characterization of
bacterial community in fresh cut salads.
International Journal of Food Microbiology,
2009; 128, pp. 484-490
16. Robertson, L.J., Johannessen, G.S., Gjerde,
B.K., Loncarevic, S., Microbiological analysis
of seed sprouts in Norway. International Journal
of Food Microbiology, 2002; 75, pp. 119-126
17. Soylemez, G., Brashears, M.M., Smith, D.A.,
Cuppett, S.L., Microbial quality of alfalfa seeds
and sprouts after a chlorine treatment and
packaging modifications. Journal of Food
Science, 2001; 66, pp. 153-157
18. Splittstoesser, D.F., Queale, D.T., Andaloro,
B.W., The microbiology of vegetable sprouts
during commercial production. Journal of Food
Safety, 1983; 5, pp.79-86
19. Taormina, P.J., Beuchat, L.R., Slutsker, L.,
Infections associated with eating seed sprouts:
an international concern. Emerging Infectious
Disease, 1999; 5, pp. 626-634
20. Viswanathan, P., Kaur, R., Prevalence and
growth of pathogens on salad vegetables, fruits
and sprouts. International Journal of Hygiene
and Environmental Health, 2001; 203, pp. 205-
213
21. Weiss, A., Hertel, C., Grothe, S., Ha, D.,
Hammes, W.P., Characterization of the cultivable
microbiota of sprouts and their potential for
application as protective cultures. Systematic
and Applied Microbiology, 2007; 30, pp. 483-
493
22. EI-Beltagy AE, Effect of Home Traditional
Methods on Quality Aspects of SomeLegumes.
MSc Thesis, Faculty of Agriculture, Menofyia
University, Shibin El-Kom, Egypt 1996.
23. Alonso R, Orúe E, Marzo F, Effect of extrusion
and conventional processingmethods on protein
and antinutritional factor contents in pea seeds.
Food Chem, 1998; 63:505–512.
24. Abu-Samaha OR, Chemical, Technological and
Nutritional Studies on Lentil.MSc Thesis,
Faculty of Agriculture, Alexandria University,
Egypt 1983.
25. El-Adawy TA, Chemical and Technological
Studies on Faba Bean Seeds. MScThesis, Faculty
of Agriculture, Menofiya University, Egypt
1986.
26. Hulse JH, Rachie KO, Billingsley LW,
Nutritional Standards and Methods ofEvaluation
for Food Legume Breeders. International Center
for Agricultural. Researchin Dry Areas
(ICARDA). Ottawa, Canada, KIG, 1977; 3Hg.
27. AOAC, Official Methods of Analysis, 14th ed.
Washington DC: Association of Official
Agricultural Chemists. Dubois M, Gilles KA,
Hamilton JK, Rebers PA, Smith F (1956)
Colorimetric methodfor determination of sugars
and related substances. Anal Chem, 1990;
28:350–356.
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To evaluate the antibacterial activity of eugenol and its mechanism of bactericidal action against Salmonella typhi. The antibacterial activity was checked by disc-diffusion method, MIC, MBC, time course assay and pH sensitivity assay. The chemo-attractant property of eugenol was verified by chemotaxis assay. The mode of action of eugenol was determined by crystal violet assay, measurement of release of 260 nm absorbing material, SDS-PAGE, FT-IR spectroscopy, AFM and SEM. Treatment with eugenol at their MIC (0.0125%) and MBC (0.025%) reduced the viability and resulted in complete inhibition of the organism. Eugenol inactivated Salmonella typhi within 60 min exposure. The chemo-attractant property of eugenol combined with the observed high antibacterial activity at alkaline pH favors the fact that the compound can work more efficiently when given in vivo. Eugenol increased the permeability of the membrane, as evidenced by crystal violet assay. The measurement of release of 260 nm absorbing intracellular materials, SDS-PAGE, SEM and AFM analysis confirmed the disruptive action of eugenol on cytoplasmic membrane. The deformation of macromolecules in the membrane, upon treatment with eugenol was verified by FT-IR spectroscopy. The results suggest that the antibacterial activity of eugenol against Salmonella typhi is due to the interaction of eugenol on bacterial cell membrane.