Improving Food Safety Genomics the branch of science

Improving Food Safety Genomics The Branch Of Science-Free PDF

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Most common causes of foodborne illnesses in Canada2. The microorganisms responsible for foodborne illnesses are generally either bacteria or viruses Bacteria are. single celled microscopic living organisms that can be found in our intestines Most of them are harmless to us in fact. some are even beneficial and help us digest food Viruses are even smaller than bacteria they survive by invading a host. cell and taking over its machinery in order to make more copies of themselves. Bacterium Sources Symptoms, Campylobacter raw or undercooked poultry beef pork and lamb raw eggs diarrhea blood or mucus abdominal pain. unpasteurized raw milk unpasteurized milk products raw nausea vomiting malaise fever. vegetables shellfish, Clostridium thick soups stews raw meat poultry and beef meat abdominal bloating pain and cramps. perfringens products gravies dried or pre cooked foods cooked beans increased gas diarrhea profuse and watery. meat pies nausea loss of appetite and weight loss muscle. aches fatigue, Listeria raw or contaminated milk soft cheeses and ready to eat abdominal bloating pain and cramps. meats such as hot dogs p t and deli meats increased gas diarrhea profuse and watery. nausea loss of appetite and weight loss muscle,aches fatigue. Salmonella unpasteurized dairy products such as raw milk and raw diarrhea fever abdominal cramps nausea and. cheese and cream filled desserts and toppings raw fruit vomiting. and vegetables especially sprouts and cantaloupes and. their juices Homemade products such as salad dressings. hollandaise sauce mayonnaise ice cream cookie dough. tiramisu and frostings, Escherichia coli improperly cooked beef raw fruits and uncooked vegetables severe stomach cramps.
E coli including sprouts untreated drinking water unpasteurized diarrhea often watery and may develop into. raw milk and raw milk products including raw milk bloody vomiting and fever generally not very. cheese unpasteurized apple juice cider and direct contact high usually less than 38 5 C 101 F. with animals at petting zoos or farms, Clostridium improperly prepared home canned low acid foods for fatigue weakness and dizziness blurred or double. botulinum example corn beets spaghetti sauce improperly stored vision dryness in the mouth throat and nose and. low acid fruit juices for example carrot juice leftover difficulty in swallowing and speaking headache. baked potatoes stored in aluminium foil and honey which nausea vomiting abdominal pain and less. has been linked to cases of infantile botulism and should not commonly diarrhea and paralysis that starts in. be fed to infants under one year of age the shoulders and arms and moves down the body. it would cut between the G and C Thus the amplified DNA fingerprint for the strain of bacteria Researchers can then. is digested into a series of longer and shorter fragments compare visually if an unidentified strain in a outbreak is. the exact pattern of which is unique to that particular strain similar to a known strain The PulseNet Canada network a. acting as a kind of fingerprint surveillance system of foodborne diseases which includes. public health laboratories from each province and two federal. In order to visualize the fragment pattern the laboratories has created a database of DNA fingerprints. fragments of DNA loaded into a gel which is a big flat sheet from disease causing bacterial strains This helps quickly. of a gelatin like substance An electric current is then run identify outbreaks of organisms such as E coli Salmonella. through the gel which causes the DNA fragments which are and Campylobacter7. negatively charged to slowly migrate through the gel toward. the positive electrode The longer fragments encounter DNA fingerprinting can trace the spread of particular. more resistance and move more slowly while the shorter strains and identify new strains when they arise but there. fragments slip easily through the gel and get further The are other genomic techniques that can help fight foodborne. electric current pulses through three different directions this illnesses One of these is polymerase chain reaction PCR. helps to separate the larger fragments more efficiently technology which targets a particular segment of a genome. and copies that segment millions of times Amplifying parts. After a set amount of time the current is turned off of the genome in this way it allows researchers to pick up on. and the result is a series of bands that represents a unique even tiny amounts of contaminating bacteria as little as a. help researchers develop strategies to fight infections from. vaccines to new antibiotics,Current research in genomics for food safety. Shiga toxin producing Escherichia coli E coli, E coli is a bacterium that lives in the digestive tracts. of most animals including humans and can be shed in. their feces Many strains of E coli are benign but a family. of strains known as E coli O157 produces toxins that can. cause a serious and sometimes fatal gastrointestinal illness. 2008 Canadian listeriosis outbreak, Above Bacteria are fingerprinted by extracting their DNA and using. enzymes to cut it into tiny pieces The pattern of long and short pieces is. unique to each bacterial strain These pieces are then loaded into a gel and. move through it by means of an electric current small pieces encounter. less resistance and move further through the gel The electric current. switches between three different directions in order to better separate the. larger DNA fragments, Below This image from the gel shows the unique fingerprint obtained.
by pulsed field gel electrophoresis for various strains of E coli Credit Listeria is a rod shaped bacterium about 0 5 micrometres wide and. United States Centres for Disease control and prevention via Wikimedia 1 5 micrometres long It can cause a foodborne illness called listeriosis. Commons that can turn deadly in people with weakened immune systems Photo. credit US Centres for Disease Control and Prevention via Wikimedia. The 2008 outbreak of listeriosis from cold cuts, was among the deadliest in Canadian history3 8 In mild. cases of listeriosis the bacteria remains in the digestive. tract and symptoms such as diarrhea and nausea last. few cells This means that contaminated samples e g food only a few days However if the bacterium invades the. products can be tested directly instead of having to grow bloodstream and central nervous system it can cause. a culture of the bacteria in the lab first this makes the test confusion loss of balance convulsions and even death. faster By using amplification to target a gene or sequence After the ingestion of contaminated food the disease can. that is unique to a particular bacterium scientists can quickly take up to 70 days to develop. detect whether that species or strain is present or not A. variation of PCR called reverse transcriptase PCR RT PCR The first signs that something was wrong. looks not at DNA but RNA which is only produced when a started in June 2008 and late July when Ontario public. gene is expressed i e turned on Thus RT PCR tells you health officials noticed higher rates of reported cases of. what genes an organism is using at a given point in time listeriosis At the beginning of August Health Canada. rather than which genes are simply present in the sample used DNA fingerprinting methods including pulsed field. This can be used to identify genes responsible for specific gel electrophoresis PFGE to confirm that a sandwich in. actions such as producing toxins or resisting antibiotics a nursing home in Toronto was contaminated with Listeria. By mid August DNA samples had confirmed that a Maple. Finally technology exists to sequence of the entire Leaf Foods plant in Toronto was the source of the outbreak. genome of a bacterium as of 2012 3144 complete bacterial and the company began to recall its contaminated. genomes had been sequenced9 This process is more products A federal investigation was launched in the. expensive and time consuming than those listed above but aftermath of the outbreak and recommendations made by. it is crucial in order to understand why some bacterial strains investigator Sheila Weatherill s report were adopted by the. cause deadly disease while others even different strains of federal government in September 2009 For example the. the same species are relatively harmless Uncovering the federal government has updated meat handling manuals. genetic basis of a strain s disease causing capabilities can and hired more food safety inspectors. in humans Many cows carry E coli O157 in their gut and a rapid test for the presence or absence of that strain A. although it does not cause disease for them it can make team at Universit Laval and the Canadian Food Inspection. its way into humans through their meat or dairy products Agency are looking to speed up in E coli O157 detection. Canadian researchers have developed a vaccine against E using a form of PCR that targets the genes they use to. coli 0157 10 but there has been debate over whether or produce their harmful toxins Their goal is to be able to. not reducing levels of E coli O157 in cows would actually identify as few as 10 cells present in 325 g of ground or trim. prevent its spread into humans and thus whether vaccination beef in less than 8 hours13. is worth the expense, On the Listeria side a team from the University of. By analysing the genome of E coli O157 scientists Alberta and from the Public Health Agency of Canada is. have determined that in the presence of certain genes using whole genome sequencing technology to develop. host animals tend to shed much higher quantities of the a database of Listeria monocytogenes strains14 They will. bacteria than normal Researchers have used genomics to then search this database for genes associated with those. show that has shown that these so called super shedding Listeria strains that cause disease Knowing these they. genes are also present in the strains of E coli O157 that then can use amplification based techniques to look for. cause outbreaks in humans this finding supports the use of these specific markers to quickly check for the presence or. vaccination in cows11 absence of dangerous strains in samples of meat or other. food products Simple tests based on this technique could. be installed on site for example in meat packing plants. So far the database contains over 200 different Listeria. monocytogenes strains,Conclusion,We all have a role to play in food safety Food. producers processors and consumers can use techniques. such as handwashing and proper labelling and sterilization. of equipment to reduce the spread of harmful organisms. But genomics provides the forensics tools we need to fully. understand how a given outbreak started knowledge that is. crucial to learning from our mistakes and preventing future. outbreaks They also offer insight in the underlying reasons. This scanning electron micrograph shows a cluster of E coli cells which why one strain is more harmful and virulent than another and. live in the guts of most mammals Some strains of E coli are benign but can point the way toward new vaccines new antibiotics and. others like E coli O157 produce toxins and cause gastrointestinal illness. in humans Credit United States Department of Agriculture via Wikimedia other new strategies such as probiotics to fight against. Commons infections In this way genomics can help everyone enjoy. Probiotic control of disease causing microbes safer food. Another way to control disease causing organisms About. is to encourage the growth of good bacteria also known. as probiotics in the intestines of animals These beneficial Science Media. organisms compete with the toxic bugs for food but they can Centre of Canada. also produce compounds that reduce the disease causing. ability of the infectious agent Researchers at the University The Science Media Centre of Canada is an independent not for profit. organization that exists to raise the level of public discourse on science. of Guelph have used genomic techniques like RT PCR to. in Canada by helping journalists access the experts and evidence based. show that when certain beneficial strains are introduced research they need in order to cover science in the news. into the guts of animals like pigs they actually cause a. reduction in the expression of genes used by bad organisms The SMCC is supported by our Gold Patron MaRS Discovery District and. Engineers Canada 132 Charter Members and ongoing support from our. to produce toxins or colonize the intestines12 Feeding these. patron organizations Backgrounder prepared for Genome Alberta May. probiotics to livestock could help them keep their own guts 2014. healthy and reduce the risk to humans at the same time. Faster detection and tracking,As mentioned amplifying sections of the genome. that are specific to a given species of bacterium can provide For more information please write to us at info sciencemedia ca. Bibliography, 1 Thomas et al 2013 Estimates of the Burden of Foodborne Illness in Canada for 30 Specified Pathogens and Unspecified.
Agents Circa 2006 Foodborne Pathogens and Disease 10 7 639 648 URL http online liebertpub com doi abs 10 1089. fpd 2012 1389, 2 Public Health Agency of Canada 2013 Food Safety Fact Sheets URL http www phac aspc gc ca fs sa fs fi index. 3 Ontario Ministry of Health 2009 2008 Listeriosis Outbreak in Ontario Epidemiologic Summary Queen s Printer for. Most common causes of foodborne illnesses in Canada2 The microorganisms responsible for foodborne illnesses are generally either bacteria or viruses Bacteria are single celled microscopic living organisms that can be found in our intestines Most of them are harmless to us in fact some are even beneficial and help us digest food Viruses are

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