Role Of E Coli And Salmonella Food Spoilage Biology Essay
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Food is sometimes contaminated with pathogenic microorganisms, there are many sort of Pathogenic bacteria it is very dangers for human, animal, salmonella one of them, it is frequently found in fowl ,eggs ,raw approved by pets similar to turtles and birds, salmonella is bacterium which is one of the commonest causes of food spoilage worldwide , there are more than 2,000 dissimilar sorts of salmonella , but with the omission of the little which typhoid or parity ,fever the sickness they cause is related, also there is a common sort of bacteria call E.coli it is akin to beef and vegetables , E.coli is short for the medical dumpy Escherichia coli is short for thing about these bacteria and lots of other bacteria is that they're not constantly harmful to you. (1,8)
E.coli generally lives indoors your intestines where it helps your body split down and digest the
food you eat , Ecoli be able to get from the insides into the blood , this is a rare sickness but it can
cause a extremely serious infection food is the commonest sources of salmonella for humans . the food may have been contaminated bacteria the source, animal or bird was infected salmonella is common with chickens some studies in 1990 showing that about 50%of of frozen and fresh chicken hold the bacteria .infections in dairy herds may show the way to contamination of milk.( 4,7 )
Outbreaks of gastroenteritis suitable to contaminated food have been reported in extra parts of the world. The probable causes of these outbreaks were suitable to the consumption of food contaminated with pathogens bacteria. Studies from many countries have given away that the microbiological quality of food manufactured for make use of in foods and drinks might be a cause for concern. (1)
Ecoli was discovered by German pediatrician and bacteriologist Theodor Escherichia in 1885, and is now classified as piece of the enterobacteriacea. (5)
Salmonella was discovered by D.E salmon, the American veterinary pathologist who original
described salmonella cholera sues in 1900. (5)
In fact several microorganisms can stay alive in food, even though food is very important to the
maintenance of life, it can also be conscientious for ill health. (1)
Structure and function of E coli Bacteria
The find structure of bacterial cells has been studied in some detail using electron microscopy of
whole cells and cells broken up into separate components.(4)
1.1 - the organism and its characteristics
Escherichia coli is a kind of gram negative bacteria, this is usually found living indoors the lower
intestine of human beings as well as animals , there are quite a few different strains of E coli
bacteria , most of which are practically, harmless.( 10 )
Although they form a very minor component of the intestinal flora, the E coli bacteria aid in the
digestion and break down of the ingested food. (6)
E coli is the type of genus, it is a catalase-positive, oxidase -negative, fermentative,
short, gram-negative, non-sporing rod, although it ferments the sugar lactose. The following
figure illustrates the size of bacteria under the electron microscope. (2)
Figure1.1-electron micrograph of
1.1.1-solation and identification of the isolates
Colonies were isolated from the Trypticase Soy Agar plates (TSA) (Oxoid UK) and Triple Sugar
Iron slants (TSI) (Oxoid UK) and incubated at 37oC for 24 hour. The isolated bacterial was
identified by cultural morphology, Gram-stain and biochemically, the colonies that showed
typical reaction in TSI and positive for cytochrom oxidase test and catalase test were confirmed
by using Analytical Profile Index 20E (API 20E). The colonies which are gives Gram positive
cocci identified by used catalase, coagulase and DNase test. (2)
1.1.2 - What these bacteria do is that they produce loads of vitamin
Amino acids and other growth factors which are immediately absorbed and used by the body.
The Ecoli bacteria that colonize in the lower intestine by adhering to intestinal lumen. (9)
However, some strains of E coli are also able of causing deadly health problems such as
severe stomach characterized by cramps and belly pain, vomiting and severe diarrhea.(10)
1.2- Structure and function of salmonella
1.2.1 -the organism and its characteristics
According to the(Adams, M and Moss, M ,1995) salmonella bacteria are the most common
cause of food borne sickness in the united states there are more than 2500 serotypes of
salmonella, only some of which cause illness in humans.(1 )
Salmonellas are members of the enterbacteracese they are gram - negative, non-spore
forming rods (typically o,5 m by 1.3m) which are faculatively anaerobic , catalase -positive,
oxidise-negative. The following figure illustrates the size of bacteria under the electron
Figure1.2.1 electron micrograph of salmonella
E.coli was discovered by German pediatrician and bacteriologist Theodor Escherichia in 1885,
and is now classified as piece of the Enterobacteriace family.(1)
the largest part E.coli strains are harmless, but some such as serotype 0157:H7, but some such as serotype 0157:H7, can cause serious food poisoning in humans.(2)
Salmonella is closely related the Escherichia genus, and some classified as part of the
enterobacteriace.( 1 )
Many Ecoli and salmonellas are responsible for a number of different clinical syndromes,
grouped here as enteritis and systemic disease.
bad stomach cramps and belly pain, vomiting, diarrhea, sometimes with blood in it two very bad
strain of Ecoli and salmonella were found in fresh spinach in 2006. ( 2 )
on the other hand, some strains of e coli and salmonella are also capable of causing deadly health
problems such as severe stomach upsets characterized by cramps and belly pain, vomiting and
severe diarrhea.( 4 )
-E coli can be differenced from salmonella on the basis of a figure of sugar-fermentation, and
other biochemical tests.(10)
-E. coli is indole positive or methyl red positive, but salmonella was negative.
-E.coli is atypical mesophile growing from 7-10c up to 50c with an optimum around 37c. (3)
-Contamination of eggs especially with salmonellas is a long-recognized problem but in the most
cases this was due to contamination of the eggshell. (4)
-furthermore biochemical tests between E coli and salmonella is difference, so typically significant group of tests used for the ability to produce:
i) Indole from tryptophan.
ii) Sufficient acid to reduce PH. (8)
-Any member of the genus salmonella presents some degree of hazard to human health, such as
S.gallinarum, typhi and pullorum. (3)
In many previous studies on the quality food microbiology criteria for the food and intake
water to these recommended by world health organization. This is because lots of countries do
not have specific notional microbiological for food spoilage.
Although, many good bacteria are needed in your body to assist it work properly, a few of these
bacteria assist you digest food (normal flour), and keep your skin clean.
However, other types of bacteria can make you ill, also convinced bacteria invade your badly and attack, causing infection.
Good hygiene and good handling practices are all prerequisites to the manufacture of good value food.
WHO's microbiological guideline for food and drinking-water quality (6)
Plate count (cfu/100ml)
1-Adams, M and Moss, M (1995) food microbiology, the royal society of chemistry,Thomas graham house (pp.181-202).
2-Anonymous. 2002. Microbiological quality of ice for cooling drinks.
Food safety authority of Ireland available from:
3-Doyle,M,beuchat,L,Montville,T,Montville,T(2001)Food Microbiology, the united states of american,washingtion(pp141-193)
4-Garbutt,J(1997) Essentials of food microbiology ,Great Britain, London pp(5-137)
5-Icmsf international commission on microbiological specification for foods (1996).
Microorganisms in foods. 5. Microbiological specifications of food pathogens
Characteristics of microbial pathogens. London, UK: blackie academic &
Professional (pp. 45-65).
6-International Commission on Micrological Specifications for foods (icmsf) (1986) microorganisms in foods (2), sampling for microbiological analysis: principles and specific applicationns.2th, university of Toronto, Canada.
7-Montville, T, Matthews, k (2005) Food Microbiology, A American Society for Microbiology, Washington pp (85-111)
8-Ray, B (2004) Fundamental Food Microbiology, Bibekray 3rd Ed, USAPP (257-269)
9- Who guidelines for drinking-water quality, vol. 1. (3rd ed.) 2004
10-Wilson, I.g., Hogg, G.M. and Barr, j.g. microbiological quality of food in
Hospital and community. j. hospital infect. 1997; 36:171-180.
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