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
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.
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.
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!
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.
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.
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.
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.
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.
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
EXPECTED OUTCOMES
- 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.
Background on Bacteria
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 Fridge Laser That Detects Bacteria Crawling All Over Food
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.
Data sheet
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.
- EU SHIPSAN TRAINET Project partnership, European manual for hygiene standards and communicable diseases surveillance on passenger ships, (2011)
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