ArticlePDF Available

Abstract and Figures

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.
Content may be subject to copyright.
* To whom all correspondence should be addressed.
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.
(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
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].
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
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.
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
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
Table 1. Antibacterial assay
Antimicrobial Micro- Concentration Zone of
agent organism inhibition
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
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
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
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
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
.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.
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.
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
1. Brul S, Coote P. Preservative agents in foods:
mode of action and microbial resistance
mechanisms. Int. J. Food Microbiol. 1999; 50:1–
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-
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-
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,
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-
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-
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-
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
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;
ResearchGate has not been able to resolve any citations for this publication.
Full-text available
Steam distillation of the dry flower buds of Syzigium aromaticum (clove) yielded 7% (w/w) of the pure light yellow oil. Gas chromatography-mass spectrometry (GC-MS) analysis of the oil revealed that the components were eugenol, caryophyllene, eugenol acetate and alpha-humelene, with eugenol being the main component. The antimicrobial sensitivity of the volatile oil against some Gram-negative bacteria (Escherichia coli ATCC 35218, Escherichia coli, Klebsiella pneumoniae, Salmonella paratyphi, Citrobacter spp. and Enterobacter cloacae), a Gram-positive bacterium (Staphylococcus aureus ATCC 25923), and a fungus (Candida albicans) showed a broad spectrum of activity. The minimum inhibitory concentration (MIC) was determined for each organism as 2.4, 1.6, 0.27, 0.016, 0.23, 1.63, 0.73 and 0.067 mg/ml for S. aureus ATTC 25923, E. cloacae, S. paratyphi, K. pneumoniae, E. coli ATTC 35218, E. coli, Citrobacter spp. and C. albicans, respectively. Antioxidant screening of clove oil with 2,2-diphenyl- picryl-hydrazyl radical (DPPH) was positive, indicating the presence of free radical scavenging molecules which can be attributed to the presence of eugenol, a phenolic compound.
Microbiological analyses of commercial sprout seeds indicated aerobic plate counts (APC) and confirmed coliforms ranging from < 30 × 102 to 40 × 103 and from 0 to > 11 × 103/g, respectively. Fecal coliforms were detected in the range from 7.3 to 11 × 102/g; Listeria or Salmonella were not detected. Seeds, pregerminated in potable water (16-18 h, 20-22°C), contained an APC ca. 1 logarithm higher than the corresponding dry seeds. Increased levels of confirmed and fecal coliforms were also detected as a result of soaking. The APC of retail sprouts ranged from 3.6 × 103 to 3.7 × 109/g. All samples contained confirmed and fecal coliforms. Coagulase positive staphylococci were detected in ca. 24% of samples analyzed. © Copyright International Association of Milk, Food and Environmental Sanitarians.
The effect of several combinations of time, pressure and temperature applied on mung bean and alfalfa seeds, on the germination capacity as well as on the reduction of the native microbial load of sprouts developed from treated seeds was studied by using response surface methodology (RSM). The germination capability of mung bean seeds was unaffected with increasing temperature and pressures up to 250MPa. Increase of temperature from 10 to 40°C has a positive effect on the viability of alfafa seeds, which decreased however as pressure increased from 100 to 400MPa. Enhanced reductions of total aerobic mesophilic bacteria, total and faecal coliforms and yeast and moulds populations were observed with increased pressure and temperature. The optimal treatment conditions for improving the safety of sprouts without impairing the germination capability of seeds were 40°C and 100 and 250MPa for alfalfa and mung bean seeds, respectively.
Repeated surveys of a factory producing vegetable sprouts showed that these foods commonly yielded aerobic plate counts of 108/g and coliform counts of 107/g. Most of the microbial growth occurred during the first two days of the germination process. Mung beans germinated in the laboratory in sterilized containers yielded comparable counts indicating that growth of the bean microflora rather than insanitary conditions was responsible. Populations were reduced to a limited extent with germicidal rinses. None of the samples yielded high counts of Bacillus cereus or Staphylococcus aureus and all were negative for salmonellae.
Different methods of rice seeds disinfection were investigated in order to limit the development of micro-organisms during sprouting. At room temperature, sodium hypochlorite at 1000 ppm or hydrogen peroxide resulted in a 2 to 3 log decrease in aerobic plate counts. Ethanol was found to inhibit germination, thus prohibiting its use. The limited effectiveness of decontaminating solutions could be because they did not access the bacteria, which was supported by the results of washing with benzalkonium chloride. Greater reduction (up to 5 log) was obtained by soaking seeds for 5 min in a sodium hypochlorite solution at 60°C.
Alfalfa seeds were treated with chlorine to determine the effect on microbial populations during soaking, sprouting, and refrigerated storage in three packaging environments. Chlorine was effective in reducing microbial populations on the seeds, but numbers increased during sprouting. Chlorine treatments had the most impact on yeast and molds during storage. Yeast and molds were significantly higher in sprouts that were stored in vacuum packages and in sprouts from non-chlorine treated seeds stored in MAP. Yeast and mold counts on all sprouts stored in perforated packaging did not significantly increase during storage. A combination of chlorine treatment of the seeds and preforated packaging of sprouts may increase the shelf-life.
Herbs and spices containing essential oils (EOs) in the range of 0.05–0.1% have demonstrated activity against pathogens, such as Salmonella typhimurium, Escherichia coli O157:H7, Listeria monocytogenes, Bacillus cereus and Staphylococcus aureus, in food systems. Application of herbs, spices and EOs with antimicrobial effects comparable to synthetic additives is still remote for three major reasons: limited data about their effects in food, strong odor, and high cost. Combinations of techniques have been successfully applied in several in-food and in vitro experiments. This paper aims to review recent in-food applications of EOs and plant-origin natural antimicrobials and recent techniques for screening such compounds.
The effects of high temperature short time (HTST) treatment compared with other conventional processes on protein, phytic acid, condensed tannins, polyphenols, trypsin, chymotrypsin and α-amylase inhibitor activities and haemagglutinating activities in Renata, Solara and Ballet pea seeds were investigated. Ballet cultivar showed highest protein, phytic acid, tannin, polyphenol contents and trypsin and chymotrypsin inhibitory activities. All pea cultivars contained trypsin- and chymotrypsin-inhibiting activity and lectins but only Solara had α-amylase inhibitory activity. Under extrusion conditions (148°C, 25% moisture and 100 rpm) this thermal processing method was the most effective in condensed tannin, trypsin, chymotrypsin, α-amylase inhibitors and haemagglutinating activity reduction, without modifying protein content as occurs by dehulling, soaking and germination treatments. Trypsin and chymotrypsin inhibitors and haemagglutinating activities in peas were more readily abolished by extrusion treatment than was chymotrypsin inhibitory activity.
Enterohemorrhagic Escherichia coli (EHEC) O157:H7 has been recognized as a major foodborne pathogen responsible for frequent gastroenteritis outbreaks. Phages and essential oils can be used as a natural antimicrobial method to reduce bacterial pathogens from the food supply. The objective of this study was to determine the effect of a bacteriophage cocktail, BEC8, alone and in combination with the essential oil trans-cinnameldehyde (TC) on the viability of a mixture of EHEC O157:H7 strains applied on whole baby romaine lettuce and baby spinach leaves. The EHEC O157:H7 strains used were Nal(R) mutants of EK27, ATCC 43895, and 472. Exponentially growing cells from tryptic soy (TS) broth cultures were spot inoculated on leaves and dried. EHEC cells were placed at low, medium, and high inoculum levels (10(4), 10(5), and 10(6) CFU/mL, respectively). Appropriate controls, BEC8 (approx. 10(6) PFU/leaf), and TC (0.5% v/v) were applied on treated leaves. The leaves were incubated at 4, 8, 23, and 37 °C in Petri dishes with moistened filter papers. EHEC survival was determined using standard plate count on nalidixic acid (50 μg/mL) Sorbitol MacConkey agar. No survivors were detected when both leaves were treated with BEC8 or TC individually at low inoculum levels after 24 h at 23 and 37 °C. When the EHEC inoculum size increased and/or incubation temperature decreased, the efficacy of BEC8 and TC decreased. However, when the two treatments were combined, no survivors were detected after 10 min at all temperatures and inoculum levels on both leafy greens. These results indicated that the BEC8/TC combination was highly effective against EHEC on both leafy greens. This combination could potentially be used as an antimicrobial to inactivate EHEC O157:H7 and reduce their incidence in the food chain.
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.