DECLARATION
I
declare that this proposal is my original work and has not been presented in
any other University/institution for consideration of any certification. This
research proposal has been complemented by referenced sources duly
acknowledged. No part of this proposal may be reproduced without the prior
written permission of the author and/or Egerton University.
NAME: KARIUKI .M.
KENNETH
ABSTRACT
Spoilage bacteria
can grow at cold temperatures i.e. psycrophiles e.g. Listeria monocytogenes
thrive at low temperatures and if present in a fridge will grow and cause illness.
Food contamination which leads to poisoning has been on the rise globally due
to the presence of cryophiles in the refrigerator. In the aspect of a science
worker, this has led to the contamination of practical samples which leads to
inaccurate results in cell cultures and preserved samples leading to indecisive
conclusions.
Missing gaps in the
field have led to the development of a refrigerator thermometer which allows
monitoring of the temperature at 40f or below while the freezer at 0f ,One
should avoid over packing of samples in a fridge to allow for cold air to
circulate around refrigerated samples to keep them chilled.You should wipe up
spills regularly to prevent cross contamination where bacteria from one sample
can spread to another and keep samples covered always with checking samples on their expiration dates to be safe.Also clean the
fridge regularly and frequently.
Objectives of the
study include:how do pyschrophiles cause refrigerated samples contamination?
and can you modify pyschrophiles to lower sample contamination by other
organisms?
The site of study
involves Njoro and its surroundings, with more emphasis on the refrigerators in
the laboratories in the biochemistry and molecular biology block in Egerton
university.
The methodology
used in collection of data involves key informant interview and the guides and
experiments involved in the study.
The expected
results of the study are the ability of the present refrigerators to adapt well
with the presence of bacteria and the inclusion of the fridge laser technique
in eradication and detection of bacteria manifesting in food.
The results will be
in conjuction with the research conclusions and the benefits of the study subject.
These include:To add more knowledge on use of fridge food extracts in targeting
various enteric bacteria, to generate a project report and the publication in a
referred journal.
Beneficiaries of
the study involves both scientists and as well food consumers as a whole.
Chapter One
Introduction
Refrigerator Bacteria
Most of us have the impression that storing foods in the
refrigerator is the best way to keep it safe from bacterial contamination, but
what we’re not aware of is that there are also types of bacteria that can grow
in cold temperatures.
Psychrophilic bacteria, otherwise known as psychrophiles,
are bacteria that are able to grow at low-temperatures. These bacteria, which
are also found in glaciers at Antarctic and Arctic continents, are the same
types that can grow inside the refrigerator.
According to studies, psychrophiles came from either
improperly packaged foods (raw meat, milk, fish, poultry, etc) or have already
been growing inside your refrigerator due to improper sanitation and
inappropriate refrigerator temperature. These types of bacteria include Coli
forms, Vibrio, Pseudomonas, and Listeria, which are all in fact quite harmful to
the human health.
Statement of the
problem.
What
are the harmful effects of Refrigerator Bacteria?
Even though some of these bacteria are not harmful by
itself alone, thus when it enters the human body (through eating foods
contaminated with it) it releases toxins which are very harmful to the health.
Psychrophilic bacteria may cause harmful health conditions such as sepsis,
diarrhea, meningitis, dysentery, food poisoning, urinary tract infections, and
gastrointestinal infections.
How to Prevent Refrigerator Bacteria from growing and
spreading inside the fridge?
- To
prevent the growth of these types of cold-loving bacteria inside your
refrigerator, you should always make sure that your fridge is at 40°F or lower.
- Avoid
opening the refrigerator door for unnecessary reasons as it may actually let
the bacteria enter your fridge.
- Always
clean and sanitize your refrigerator regularly using antibacterial bleach
cleaners.
- Clean
spills right away and organize the food placement inside your fridge. The best
practice is to place raw meat, poultry, or fish at the lower part of the
shelves to avoid its juices from mixing into other foods.
- It
is also strongly advised to place raw food into tight-sealed containers to
avoid food contamination.
- Always
separate raw foods from cooked ones.
- Ensure
also that you dispose old foods to avoid cross contamination. Check for
discoloration or molds in foods and immediately dispose them. Molds are often
signs of bacterial growth.
To sum it all up, despite the fact that bacteria can actually
grow inside the refrigerator too, there are plenty of ways to counterpart it.
And the main solution to keep your foods safe, clean, bacteria-free is to
always maintain cleanliness in your surroundings. Following the preventive tips
above will also give you a head start.
Remember, prevention is always better than any cure.
Justification of the study.
How to Have a Bacteria-free Refrigerator
Our refrigerator is basically one of our main storages
for food, not to mention that it helps prevent or slow down spoilage. But
apparently, there are some types of bacteria that can still thrive inside the
refrigerator.
Here are some great tips on how to have your refrigerator
safe and bacteria-free!
Set the
perfect temperature
Make sure that you set your refrigerator at 40°F or lower
as it is the most ideal temperature to prevent or slow down the growth of
harmful bacteria. Some refrigerators also have built-in thermometer that
monitors its internal temperature. If your refrigerator does not have one, you
can always opt for an appliance thermometer. Appliance thermometers are
designed specifically to monitor and supply accurate refrigerator temperatures.
Keep
the door closed
Make sure that your refrigerator’s door is closed
properly and tightly. Avoid opening it many times than it is necessary and
close it as soon as possible when you are not using it. By letting hot air to
enter your cold storage enables increased growth of bacteria.
Refrigerate
food safely
When storing foods inside the refrigerator, you must
always ensure to place it in tight-sealed containers to retain its moisture and
prevent it from spreading to other foods. For instance, large portions or meat
or poultry should be divided into smaller portions and placed inside a
container before refrigerating. It is important that you seal the containers of
raw meat, fish, or poultry tightly to avoid its juices from mixing or
contaminating to other foods.
Avoid mixing your
foods
You should never mix raw foods from cooked ones. Raw
meat, poultry, or fish contains several bacteria from the gut of the animal.
Make it a habit to place raw meat at the bottom of the shelf to avoid its
juices from dripping into other foods, but it is still a best practice to have
them into seal-tight containers.
Clean your fridge
This is basically one of the crucial things that you
should do – constantly clean your refrigerator to ensure that it is safe and
bacteria-free for storing foods. Wipe food spills immediately to avoid growth
and spread of bacteria. When cleaning, make sure to use anti-bacteria cleaning
products or bleach and clean the surfaces thoroughly. It is also advisable to
use hot soapy water while cleaning, and then rinse it thoroughly.
Dispose older foods
Make sure that you throw old and spoiled foods as it may
cause growth and spread of bacteria and molds which may contaminate other
foods. To avoid having your food stay too long in your refrigerator and spoil,
practice moving your older foods in the front row of your fridge. Doing this
lets your food get seen and eaten before it goes out-of-date.
Objectives
General objectives
- To
evaluate potential effect of growth of
E. coli, Coliforms, Vitrio and
listeria on nutrient agar media.
- To enhance bacterial classification in combating
life threatening bacterial infections.
Specific objectives
- To determine the most present bacteria in
refrigerated food plus the biochemical testing of grown bacteria .
- To deduce the coexistance of these bacteria
by cultring in the same petri dish and allowing for analysis .
Hypothesis
Alternate
hypothesis.
- The presence of bacteria in refrigerated food
has minimal damage on human health plus has serious consequences on infection
towards human health.
Null hypothesis
-
- To generate a comprehensive report on the
project.
- To provide viable and reproducible data that
can be used to revolutionize antibiotic therapy.
Limitations to the study
Even
though studies have shown that fridge swab extracts exert antibacterial and synergistic
effects with conventional antibiotics, further investigations are needed for
isolation, identification, and characterizations of active principles to obtain
compounds with more potent antibacterial and synergistic activity.
Chapter
Two
Literature Review
What are
Psychrophilic Bacteria?
Psychrophilic bacteria or psychrophiles are a type of bacteria that can grow in
refrigerated temperatures. The psychrophiles found in refrigerators are
actually the same microbes that can be found in Arctics and Antartic glaciers.
The reason why these bacteria are cold-resistant unlike their hot-lover
relatives is because they contain an enzyme that none of the others have. These
microorganisms are commonly responsible for faster spoilage of foods in
refrigerators and may also cause contamination to some foods.
There
are two different families of bacteria: pathogenic
bacteria, the kind that cause food borne illness, and spoilage bacteria, the kind of
bacteria that cause foods to deteriorate and develop unpleasant odors, tastes,
and textures. Pathogenic bacteria can grow rapidly in the “Danger
Zone,” the temperature range between 40°F and 140°F (4.4 °C and 60 °C).
Because they do not generally affect the taste, smell, or appearance of a food,
one cannot tell that a pathogen is present. Spoilage bacteria can grow
at cold temperatures, such as in the refrigerator. Eventually they cause
food to develop off or bad tastes and smells. Most people would not choose to
eat spoiled food, but if they did, they probably would not get sick. However,
some bacteria such as Listeria monocytogenes thrive at cold
temperatures, and if present, will grow in the refrigerator and could cause
illness.
How can these bacteria be harmful to human
health?
Improper packaging or processing of foods (which may
include raw meat, poultry, fish, eggs, and milk) can cause it to be
contaminated with psychrophilic bacteria. Unhygienic refrigerators and freezers are also some of the
possible breeding places of these cold-loving microbes.
As such, when your food gets contaminated with these
bacteria and you eat it, the bacteria will grow inside your body and thus
present pathogenic conditions. Some bacteria may not really be harmful alone
unless when they expose toxins into food which causes food poisoning.
Pseudomonas, Coli forms, Listeria, Vibrio, and Molds such as Cladosporium and
Penicillium are some examples of bacteria that are quite harmful when it is
inside of the human body. Salmonella is also a common type of bacteria that
contaminates refrigerated foods and may cause serious illness.
Psychrophilic bacteria usually cause conditions such as
sepsis, meningitis, diarrhea, irritable bowel syndrome, gastrointestinal
infections, dysentery, and food poisoning. Immunocompromised people (like
pregnant women, HIV or AIDs patient, and those who are undergoing chemotherapy
treatment), newborns, and likewise those who have pre-existing health problems,
are just some of those who have greater risks of developing harmful conditions
caused by these bacteria.
Our body’s immune system on the other hand, when exposed
to the bacteria’s harmful toxins, triggers its defense mechanism to get rid of
these “foreign objects” thus causing nausea, diarrhea, or fatigue.
While the negative
conditions brought by psychrophilic bacteria may not seem as fatal as other
serious illnesses, there are actually some cases from which it led to the
patient’s death due to plain ignorance. This means that you should not wait for
the symptoms to get worse before you take action. Or better yet stick with the
“prevention is better than cure” rule by eliminating the causes of these
bacteria’s growth. By making sure that your refrigerator is clean,
well-handled, and hygienic ensures that you don’t have to deal with these harmful bacteria.
One of the factors in food
poisoning is not only bacterial growth in food but the toxins that bacteria can
produce as they grow. While thorough cooking will destroy the bacteria as long
as there are not overwhelming quantities present, heat will not destroy the
toxins.
The best way to avoid
bacterial growth and the subsequent toxins is to follow proper handling instructions: keep meat cold, wash your hands and any surface that comes in contact
with raw meat, never place cooked meat on a platter that held raw meat, and
cook food to safe internal temperatures.
There is an exception to the
general rule that refrigeration minimizes bacterial growth: Listeria
monocytogenes, a bacteria that causes serious illness, can grow at refrigerator
temperatures. Make sure you clean up spills in the fridge immediately.
Thoroughly cook meat and poultry to 160 F and check it with a food thermometer.
Hot dogs and deli meats are especially problematic with this bacteria, which is
why the government recommends pregnant women and those in high-risk groups
avoid those foods along with soft cheeses, smoked seafood, pates, and meat
spreads.
Bacteria are present in
everything. It’s impossible to completely avoid bacteria. Some bacteria are
helpful to us and other varieties are very harmful. It’s the harmful bacteria
that we want to minimize in the food we eat.
Bacteria grow best at
temperatures between 40 F and 140 F. They multiply very rapidly at those
temperatures in ideal strata – that is, perishable foods like meat and dairy
products.
That’s why
it’s so important to keep perishable foods refrigerated at temperatures below
40 F.
At refrigerator temperatures,
that is, 32 F to 40 F, bacteria can still grow, but that growth is slowed
dramatically. That’s why you must use raw perishable food within a certain time
frame, usually 2 to 3 days, even when it is properly refrigerated.
As bacteria grow, they can
produce toxins that are not disabled, or rendered harmless, by heat. C. botulinum is the most notorious of these
bacteria; the toxin is almost inevitably fatal. But since that bacteria grows
in an anaerobic (oxygen-poor) environment, it is most associated with canned
foods or foods stored in oil.
Other bacteria, like
Staphylococcus aureus, produces a heat-stable toxin that is of concern. Salmonella creates illness, not through toxins,
but the bacteria itself.
These toxins are
not produced immediately by the bacteria but can take hours or even days to
develop. Properly handling and storing meats and dairy products will minimize
the risk of these toxins. Most
of these microorganisms, are well able to grow down to 0°-2°C, can enter the
refrigerator through raw and improperly packaged foods (typically meats, eggs
and milk) or even through an open refrigerator door during cargo by poor
cleanliness refrigerator seals, or are already growing from lack of proper
sanitation or warm temperature, and, if ingested, cause dangerous food borne
illnesses, including sepsis, diarrhoea, meningitis, dysentery, food poisoning,
urinary tract infections, and gastrointestinal infections. In addition, the
mould species Penicillium and Cladosporium, always present in the refrigerator
sides, produce poisonous compounds (mycotoxin, aflatoxins) that spread
throughout the refrigerated foods and are known to be potent carcinogens.
Cruise ships are at increased risk of food
contamination from these “psychrophilic microorganisms”, because large amounts
of foods are consumed every day. Moreover, not all foods are consumed during
the voyage, because the ships must keep a percentage in reserve to allow for
delays, in refrigerated or frozen conditions.
The new technique is simple in principle.
Bacteria such as salmonella have hair-like flagella that they use to propel
themselves across surfaces. This movement turns the surface of contaminated
food into an ocean of writhing microorganisms. It is this movement that Yoon
and co have worked out how to spot.
Their method is straightforward. When a red,
coherent laser beam hits biological tissue, it is scattered through the
material. This scattering causes the light to interfere, creating a random
pattern called laser speckle.
Since bacteria on the surface of food also
scatter light, this influences the speckle. And as the bacteria move, the
speckle pattern changes. “By detecting the decorrelation in the laser speckle
intensity patterns from tissues, the living activities of microorganisms can be
detected,” say Yoon and co.
All that is needed to monitor this change is
a camera that can record the change over a few seconds. Yoon and co use one
that takes images at a rate of 30 times a second and then process the images by
subtracting one from another to reveal any difference.
They’ve put their gear through its paces with
a set of experiments on chicken breast. They began by contaminating samples of
chicken breast with the common bacteria Escherichia
coli and Bacillus cereus, which are common causes of food borne
illness. They then zapped each of the samples, and a control, with a laser
while recording the speckle with a camera.
The results clearly show the utility of the
technique. The image subtraction technique quickly reveals which samples are
contaminated and to what degree. The technique picks up both types of bacterial
contamination, although it cannot distinguish between them. It also
demonstrates that uncontaminated meat shows little or no change in the laser
speckle pattern over time.
That’s an interesting result. Monitoring
laser speckle is quick and easy to do with cheap equipment that can be
retrospectively fitted to food processing lines. And it requires little
specialized expertise. Crucially, the technique does not require contact with
the meat and so can be done at a distance. It can also see through transparent
plastic packaging, which does not influence the speckle pattern.
That could have an important impact in many
parts of the world, particularly in developing countries that do not have easy
access to microbiology laboratories. And the equipment is so cheap and simple
that it could easily be fitted to ordinary refrigerators designed for the home.
There are limitations, of course. Although
the technique detects different types of bacteria, it cannot distinguish
between them. And of course, it cannot spot contaminants that do not change the
laser speckle over time. So it wouldn’t pick up viral contaminants, such as
norovirus, which is responsible for five million causes of food borne illness a
year in the U.S. Neither does it detect the toxins produced by bacteria, which
can cause illness even when the bacteria have been killed off.
Nevertheless, the new technique has the
potential to significantly improve food hygiene and thereby reduce the number
of cases of food poisoning each year.
Chapter
3:
Methodology
Laboratory
procedure
This involves the collection of samples from difeerent
fridges around the university premises by inclusion of the available
laboratories in the department of biochemistry and molecular
biology.Preparation of media according to the manufacturers instructions is
allowed and the appropriate mediia is allowed to enhance the complexity of the the application of the bacteria into a
suitable nutrient agar and the culturing of the bacteria in the media by the
use of cold temperature exposure . The samples are then refrigerated for a time
of 24hours which involves the incubation period of the sample.
There is a preparation of a biochemical media which the
growth media can exhibit the desired properties of a positive control which
involves the inclusion of a negative control which allows the best acquistion
of a desired output. The biochemichal tests involves simmons citrate test,
Methyl red vorges proskeur test, and the motility indole lysine test which
involve the characterization of the bacteria according to the specific objectives.
Study area
Njoro is an urban
town in the out skirts of Nakuru kenya.It has a wide variety of people and
tribes , not to say colour.The climate involves a very cold place suitable for
a growth of a variety oof crops and has
also a hot environment at a
certain time of the year.
Egerton University
is situated miles from Njoro town and on the highway to Mau narok and has a
town centre just outside the university gate. The place has a huge population
of university workers , students and the native community who make up the
majority of the population.
Swab extracts
|
|
Swab
extract
|
+Ve
control
|
|
Concentration
(g/µl)
|
0.25
|
|
|
0.5
|
|
|
0.75
|
|
|
|
|
Trials
|
1
|
2
|
3
|
1
|
2
|
3
|
1
|
2
|
3
|
|
|
Test
microorganism
|
|
|
|
|
|
|
|
|
|
|
|
Coli
forms
|
|
|
|
|
|
|
|
|
|
|
|
Pseudomonas
|
|
|
|
|
|
|
|
|
|
|
|
Vibrio
|
|
|
|
|
|
|
|
|
|
|
|
Listeria
|
|
|
|
|
|
|
|
|
|
|
|
Budget
|
Equipment
|
Quantity
|
Cost
|
|
Agar Petri dishes
|
20
|
360
|
|
Gloves
|
I box
|
350
|
|
Nutrient agar
|
125g
|
500
|
|
Marker pen
|
1
|
100
|
|
Test microorganisms ( E. Coli ,P.
aeruginosa, S. aureus)
|
I vial each bacteria
|
6000
|
|
Whatman filter paper
|
3
|
300
|
|
Methanol
|
I litre
|
250
|
|
Dropper
|
3
|
50
|
|
Typing and printing of proposal and report
|
2
|
500
|
|
TOTAL
|
|
8410
|
Work Plan
|
|
ACTIVITIES
|
Period in months
|
|
|
|
2018
|
January
2018
|
February-March
2018
|
April
2018
|
June
2018
|
July
2018
|
|
|
Problem
Formulation
|
|
|
|
|
|
|
|
|
Literature search and review
|
|
|
|
|
|
|
|
|
Proposal writing
|
|
|
|
|
|
|
|
|
Pilot testing of data collection tools
|
|
|
|
|
|
|
|
|
Collection of data and carrying out of
laboratory experiments
|
|
|
|
|
|
|
|
|
Data analysis
|
|
|
|
|
|
|
|
|
Final project report writing
|
|
|
|
|
|
|
|
|
Submission of report and final defense
|
|
|
|
|
|
|
REFERENCES:
- : http://arxiv.org/abs/1603.07343 : A Simple and Rapid Method for
Detecting Living Microorganisms in Food Using Laser Speckle Decorrelation.
- Jackson V, Blair IS,
McDowell DA, et al. The incidence of significant food borne pathogens in
domestic refrigerators. Food Control 2007; 18: 346-51.
- Behravesh CB,
Williams IT, Tauxe RV. Emergin food borne pathogens and problems: expanding
prevention efforts before slaughter or harvest. In: Institute of Medicine (US).
Improving Food Safety Through a One Health Approach: Workshop Summary.
Washington (DC): National Academies Press (US); 2012. A14. Available from:
http://www.ncbi.nlm.nih.gov/books/NBK114501/
- Haddad N, Burns CM,
Bolla JM et al. Long-term survival of Campylobacter jejuni at low temperatures
is dependent on polynucleotide phosphorilase activity. Appl Environ Microbiol
2009; 75: 7310-18.
- Rossvoll E, Ronning
HT, Granum PE et al. Toxin production and growth of pathogens subjected to
temperature fluctuations simulating consumer handing of cold cuts. Int J Food
Microbiol 2014; doi.: 10.1016.
- Ingham SC. Growth of
Aeromonas hydrophila and Plesiomonas shigelloides on cooked crayfish tails
during cold storage under air, vacuum and a modified temperature. J Food Prot
1990; 53: 665-67.
- De Jonghe V,
Coorevits A, Van Hoorde K. Influence of storage conditions on the growth of
Pseudomonas species in refrigerated raw milk. Appl Environ Microbiol 2011; 77:
460-70.
- Sautour M, Dantigny
P, et al. A temperature-type model for describing the relationship between
fungal growth and water activity. 2001; 67: 63-69.
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