2Foodborne Pathogensa biological infectious agent (Microorganism) that causes Foodborne illness to host (referred to as food poisoning) is any illness resulting from the consumption of contaminated food.
3Foodborne Pathogens:Foodborne pathogens are the leading causes of illness and death in less developed countries killing approximately 1.8 million people annually.In developed countries foodborne pathogens are responsible for millions of cases of infectious gastrointestinal diseases each year, costing billions of dollars in medical care and lost productivity.
4New foodborne pathogens and foodborne diseases are likely to emerge driven by factors such as pathogen evolution, changes in agricultural and food manufacturing practices, and changes to the human host status.There are growing concerns that terrorists could use pathogens to contaminate food and water supplies in attempts to incapacitate thousands of people and disrupt economic growth.
6Staphylococcus aureus TAXONOMYGram positive coccus (producing an exotoxin)Source of contamination of food- nose and skin of humans and animals- high level in people with- skin infection- heavily colonised skin disease
7Contamination by food handler Eliminated by pasteurizationMicrowave decreases countsFat/ sugar/ salt protects the organismUsually about 106 / g needed to produce sufficient toxinGenerally low numbers are allowed in food
8GROWTH REQUIREMENTS * Temperature range 7 - 48 o C (optimum 37 oC) * pH range(optimum 6 - 7)* Facultative anaerobe
9REQUIREMENTS FOR TOXIN PRODUCTION Range is more limited than growth rangeoptimum temperature 40 – 45 o CAw above 0.85
10Staphylococcal Exotoxin (Enterotoxin / Neurotoxin) * Resistant to proteolytic enzymese.g. trypsin in the gut* Resistant to heat
11Mechanism of ActivityToxin (exotoxin) is performed and ingested in foodStimulates neural receptors in the gastrointestinal tractVomiting within approx 4 hours (1-6 hours) after ingestion of toxinThe toxin can also induce diarrhea, nausea, headache
12Examples of foods implicated in outbreaks Salted meatsCold cooked meatsPoultryCustardCream filled bakery products(whipped cream)Mayonnaiseegg
13MOST OUTBREAK ASSOCIATED WITH ONE OR MORE OF : PREVENTIONMOST OUTBREAK ASSOCIATED WITH ONE OR MORE OF :Inadequate in refrigerationFood prepared in advancePoor personal hygieneModerate cooking or heat processingHolding food in warmerSO…* Control post-process contamination* Control temperature abuse (cooking/ holding/ refrigeration)* Handle food correctly* Good quality raw material
14Salmonella Enterobacteriaceae Gram Negative, Short Rod TAXONOMYEnterobacteriaceaeGram Negative, Short RodNon spore formingPeritrichous flagellaRESERVIORIntestinal of domestic and wild animalWater, Sewage, Environment
15GROWTH REQUIREMENTS * Temperature range optimum 37 oC 42 oC used for selective enrichment* pH range4 - 9* Facultative anaerobe
16Found in many foods :Contamination directly or indirectly with animal or human feaces- Raw/Undercooked eggs- Uncooked meat- Raw milk and milk products- Poultry and poultry products- Skim milk powder- Ice-cream- Mayonnaise- Chocolate- Cantaloupes
17Clinical Diarrhoea Vomiting Antibiotics minimal effect Organism may be excreted for weeksSome outbrakes have shown very low infective dose causing death in infants, elderly and immunosuppressed.
18PREVENTIONCorrect food hygiene – direct or indirect feacal contaminationCorrect food processing – heating / cooling / storing.Correct personal hygiene to control secondary spreadFood handlers should have consecutive negative feacal cultures before returning to work with food.
20Coliform is the name of a test for the Enterobacteriaceae family. commonly-used bacterial indicator of sanitary quality of foods and water.They are defined as rod-shaped Gram-negative non-spore forming organisms.Some genus can ferment lactose with the production of acid and gas when incubated at 35-37°C.abundant in the feces of warm-blooded animals, but can also be found in the aquatic environment, in soil and on vegetation.they are easy to culture and their presence is used to indicate that other pathogenic organisms of fecal origin may be present. Fecal pathogens include bacteria, viruses,or protozoa and many multicellular parasites
21Escherichia coli Member of the coliform group Gram Negative, rod and Non-sporulatingFacultative anaerobicferment lactose at 44°C in the fecal coliform testWhen cultured on an EMB plate,a positive result for E. coli is Metallicsheen colonies on a dark purple media.
22ReferenceAdams, M.R. and Moss, M.O., Food Microbiology, 2008