department of food science lecture 12: march 2, 2015 microorganisms in foods lecture 12 march 2,...
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Department of Food Science
Lecture 12: March 2, 2015
Microorganisms in Foods
Lecture 12
March 2, 2015Dr. Ponnusamy
Department of Food Science
Lecture 12: March 2, 2015
Food Microbiology
• The Beneficial Microorganisms….. Probiotics Prebiotics
• The Not-So-Beneficial Microorganisms.. Food borne Illness Food Spoilage Food borne pathogens
Department of Food Science
Lecture 12: March 2, 2015
The Good and Bad of Microorganisms
Harmful effects:
• Food borne diseases
• Food infections
• Food poisoning
• Viral borne
infections
• Food spoilage
Beneficial effects: • Fermentation
Cheese Yogurt Fermented sausages Wine Sauerkraut
• Probiotics
Department of Food Science
Lecture 12: March 2, 2015
Let’s start with the GOOD bacteria……..
https://www.google.com/search?q=picture+of+yogurt+being+eaten&rls=com.microsoft:en-us:IE-Address&rlz=1I7ADSA_enUS482&tbm=isch&imgil=o5qYjm1PEqRF_M%253A%253Bhttps%253A%252F%252Fencrypted-tbn0.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9GcRwMHbsQngIULwGzHuSQlX93jdsZs2xsmiikPz2Ln7AKTonwaI4%253B460%253B360%253BXiVKLAXG2JDIXM%253Bhttp%25253A%25252F%25252Fhealthyoffspring.com%25252Fpage%25252F2%25252F&source=iu&usg=__z61PRCjckyV3due-HkUDC2w-OSo%3D&sa=X&ei=bgMOU5-BGfG_sQT09oKoDw&ved=0CC0Q9QEwAw&biw=1366&bih=599#facrc=_&imgdii=_&imgrc=OeBZHHcAL2Y5mM%253A%3Bc8pZa3XH0XmPHM%3Bhttp%253A%252F%252Fstatic6.depositphotos.com%252F1008277%252F557%252Fi%252F950%252Fdepositphotos_5571850-Little-Boy-Is-Eating-Yogurt..jpg%3Bhttp%253A%252F%252Fdepositphotos.com%252F5571850%252Fstock-photo-Little-Boy-Is-Eating-Yogurt..html%3B1024%3B834
Department of Food Science
Lecture 12: March 2, 2015
PRO- & PRE- BIOTICS
FOR THE COLON
•The friendly bacteria for fermentation are called the probiotics (pro-life)
•Certain fibers in food, called prebiotics, specifically support these probiotic bacteria.
Department of Food Science
Lecture 12: March 2, 2015
Foods for Colon Health
• Probiotics: Live bacteria Improve intestinal microbial balance
• Yogurt – ‘live with active cultures’
Probiotic Therapy: Consuming products with beneficial bacteria and supplements
Department of Food Science
Lecture 12: March 2, 2015
Probiotics
• Means ‘for life’• Live microorganisms which when administered in
adequate amounts confer a health benefit on the host
Source: FAO/WHO Report October 2001
Bifidobacterium adolescentis
http://microbewiki.kenyon.edu
http://www.gutflora.org
Lactobacillus rhamnosus
http://www.institut-rosell-lallemand.com
Saccharomyces boulardii
Department of Food Science
Lecture 12: March 2, 2015
Foods for Colon Health• Prebiotics: Fiber
Stimulate growth of beneficial bacteria in colon
• Inulin, Polydextrose, Resistant starch Sources: yogurts fortified with prebiotics,
wheat, whole grain and dairy products, legumes, leafy greens, artichokes, bananas, berries, chicory, garlic, honey, leeks, onions…………… to name a few
Department of Food Science
Lecture 12: March 2, 2015
Why abnormal gut microflora?
Type 2 diabetesCancerCoronary heart
diseaseCholesterolObesityDigestive disorders
(IBD)AllergiesCommon coldInfectionsDiarrheaLactose intolerance Impaired immunity
Type 2 diabetesCancerCoronary heart
diseaseCholesterolObesityDigestive disorders
(IBD)AllergiesCommon coldInfectionsDiarrheaLactose intolerance Impaired immunity
SmokingWestern type diet AgePhysical activity levelPublic health practicesSmaller FamiliesPremature deliveryCesarean sectionPerinatal antibiotic use
Lack of breastfeeding
SmokingWestern type diet AgePhysical activity levelPublic health practicesSmaller FamiliesPremature deliveryCesarean sectionPerinatal antibiotic use
Lack of breastfeeding
Health ConditionsHealth Conditions
Abnormalgut
microbiota
FactorsFactors
Department of Food Science
Lecture 12: March 2, 2015
The Good Microorganisms: ProbioticsHuman probiotics:
where?
• Gastro-intestinal
• Skin
• Scalp
• Oral cavity
• Underarm and feet
• Urogenital
including vaginal
Expected Benefits with Consumption
• Increased tolerance to infections
• Control of diarrhea
• Reduction of blood pressure
• Cholesterol reduction
• Allergy control
• Immunomodulation
• Cancer reduction
http://www.cook.rutgers.edu/~dbm/foodMicrobiologynp.pdf
Department of Food Science
Lecture 12: March 2, 2015
Global Probiotic Market• The market is currently valued at $22.6 billion and
projected to reach $28.8 billion in 2015• Target consumers are mainly located in Japan,
Europe and USA• Growth factors include:
Consumer understanding of the effect of nutrition on health
Rising healthcare costs
Source: “Global Probiotic Market to Grow – Analyst.” FLEXNEWS. 27 Sept 2010. Web. 27 Sept 2010.
Department of Food Science
Lecture 12: March 2, 2015
Probiotic Products• Dairy foods
Beverages, yogurt, kefir, ice cream, cheese
• Non-dairy foods Beverages, bars, chocolate, cereal, pizza,
condiments
• Dietary supplements Infant formula, drops, tablets, capsules, powders
• Clinical therapeutics
Department of Food Science
Lecture 12: March 2, 2015
Rapid Emergence of Probiotics• The reported health benefits of probiotic bacteria
found in cultured and dairy products include:• improving digestive absorption• cleaning the intestinal tract• production of enzymes• increasing the availability of vitamins and
nutrients- especially vitamin B, vitamin K, lactase, fatty acids and calcium
Department of Food Science
Lecture 12: March 2, 2015
Probiotic Market Overview
Source: Nexis - Dairy Field, March 2007, Euromonitor Industry Profile – Global Dairy Products Market, October 2006
• The total international probiotic market in yogurts, kefirs and fermented dairy beverages translates to $10 billion with growing annual sales*
• US Sales of probiotics was estimated to be approximately $764 million and was expected to rise to $1.1 billion in 2010 – an average annual growth rate (AAGR) of 7.1%**
• The appeal of such benefits served to bolster yogurt sales significantly in a number of markets and made probiotic yogurt the second fastest growing dairy products category, with CAGR growth of more than 16%, between 1998 and 2005***
*Dairy Field, 2006; **Business Communications Company (BCC) Research, 2005; ***Euromonitor
Department of Food Science
Lecture 12: March 2, 2015
The Not-So-Beneficial Microorganisms
https://www.google.com/search?q=germs+on+produce+pictures&rls=com.microsoft:en-us:IE-Address&rlz=1I7ADSA_enUS482&tbm=isch&imgil=QtHGz_9TtRLPXM%253A%253Bhttps%253A%252F%252Fencrypted-tbn2.gstatic.com%252Fimages%253Fq%253Dtbn%253AANd9GcRmHXxPWy5A73-7HurotlxjmGlcpfV4wuEvSui5PwDD2DlOm0LT%253B236%253B156%253BrYPGWw9beywerM%253Bhttp%25253A%25252F%25252Fwww.pinterest.com%25252Fmirabellegalian%25252Fbet-u-didn-t-know%25252F&source=iu&usg=__2aNSojfg366xTAli6LZKHrZ8LHk%3D&sa=X&ei=lQQOU-atGeHisATm0oKADw&ved=0CDcQ9QEwCA&biw=1366&bih=599#facrc=_&imgdii=YU0ahnquRQ1FaM%3A%3BRXPpoRUDAwy73M%3BYU0ahnquRQ1FaM%3A&imgrc=YU0ahnquRQ1FaM%253A%3BHHUHgAJgvy6nuM%3Bhttp%253A%252F%252Fzoonotica.files.wordpress.com%252F2011%252F11%252Fcouple_of_bacteria.jpg%3Bhttp%253A%252F%252Fzoonotica.wordpress.com%252F%3B350%3B362
Department of Food Science
Lecture 12: March 2, 2015
The Not-So-Beneficial Microorganisms
• The ones that cause: Food borne Illnesses Food infections Food Poisoning/ Intoxications Food Spoilage
Department of Food Science
Lecture 12: March 2, 2015
Pathogens in Foods
• A pathogen is a microorganism capable of producing a disease
Bacteria
Viruses
MoldsPrions
Parasites
Department of Food Science
Lecture 12: March 2, 2015
Foodborne Illness
Illness occurring as a result of ingesting food or water contaminated with:
1. Infectious agents• Bacteria, molds, yeasts• Viruses, prions• Parasites
2. A toxin or chemical • Bacterial toxin• Pesticides, Heavy metals• Other chemical contaminants
Department of Food Science
Lecture 12: March 2, 2015
Harmful: Food Infection vs. Food PoisoningFood infection
• Live cells delivered by contaminated food; organism multiply once food is ingested Salmonella; E. coli
Food poisoning (intoxication)
• Caused by preformed toxin in the food; organism may or may not be alive and growing
• Clostridium botulinum ( in canned foods); Staphylococcus aureus
Department of Food Science
Lecture 12: March 2, 2015
FINDINGS: CDC Estimates of Food borne Illness in the United States- 2011
• CDC estimates that each year roughly 1 in
6 Americans (or 48 million people) gets
sick, 128,000 are hospitalized, and 3,000
die of food borne diseases.
Department of Food Science
Lecture 12: March 2, 2015
• CDC has estimates for two major groups of
foodborne illnesses:
• Known foodborne pathogens— 31
pathogens known to cause foodborne illness.
• Many of these pathogens are tracked by
public health systems that track diseases and
outbreaks.
Department of Food Science
Lecture 12: March 2, 2015
• Unspecified agents—
• Agents with insufficient data to estimate agent-specific burden; known agents not yet identified as causing foodborne illness;
• microbes, chemicals, or other substances known to be in food whose ability to cause illness is unproven; and agents not yet identified.
• Because you can’t “track” what isn’t yet identified, estimates for this group of agents started with the health effects or symptoms that they are most likely to cause—
acute gastroenteritis.
Department of Food Science
Lecture 12: March 2, 2015
CDC Estimated Data on Foodborne Disease in the United States- 2011
From : W_Fanaselle FDA, CFSAN
Top 5 PathogensEstimated number of
hospitalizations
Salmonella, nontyphoidal
19,336
Norovirus 14,663
Campylobacter spp. 8,463
Toxoplasma gondii 4,428
E.coli (STEC) O157 2,138
Department of Food Science
Lecture 12: March 2, 2015
CDC Estimated Data on Foodborne Disease in the United States- 2011
From : W_Fanaselle FDA, CFSAN
Top 5 PathogensEstimated number of
deaths
Salmonella, nontyphoidal
378
Toxoplasma gondii 327
Listeria monocytogenes 255
Norovirus 149
Campylobacter spp. 76
Department of Food Science
Lecture 12: March 2, 2015
Specific Product Concerns
• Produce
• Imported foods
• Juice
• Eggs
• Raw milk
Department of Food Science
Lecture 12: March 2, 2015
2006 Nationwide Outbreak of E. coli
• Source: Spinach• Illness in 26 states
204 cases of illness reported to the CDC 31 cases involving a type of kidney
failure 104 hospitalizations and 3 deaths
• Four implicated fields on Four ranches• Cause: Cattle and pig feces
Department of Food Science
Lecture 12: March 2, 2015
2008-9 Peanut Salmonella RecallMore than 31 million pounds
125 items affected in salmonella probe
• Case count is 677 in 45 states with latest confirmed, most recent reported illness beginning on February 8, 2009
• The outbreak is continuing, though the numbers of new cases have declined modestly since December.
• FDA and CDC are concerned that illness will continue to occur if people eat recalled peanut-containing products that are still on their shelves at home.
• Consumers should check at home for recalled peanut butter containing products and discard them.
• Major national brands of jarred peanut butter found in grocery stores are NOT on the Peanut Corporation of America (PCA) recall list.
http://www.cdc.gov/salmonella/typhimurium/update.html
Department of Food Science
Lecture 12: March 2, 2015
Listeria outbreak• In 2011, a Listeria outbreak in cantaloupe
caused 30 deaths and 146 illnesses across 28 states.
• Listeria is particularly dangerous because it lives in soil, infecting the inside of cantaloupe as well as the outside.
• Additionally, it thrives in cold temperatures (such as refrigerator).
Department of Food Science
Lecture 12: March 2, 2015
Outbreaks Involving Raw Milk
• Outbreaks from dairy products was studied from 1993 to 2006 in all 50 states
• CDC Reports: The rate of outbreaks caused by unpasteurized milk (often called raw milk) and products made from it was 150 times greater than outbreaks linked to pasteurized milk
• http://www.cdc.gov/media/releases/2012/p0221_raw_milk_outbreak.html
Department of Food Science
Lecture 12: March 2, 2015
Safety Concerns over Raw Milk
• Raw milk product outbreaks led to much more severe illnesses, and disproportionately affected people under age 20.
• 60 percent of patients were younger than age 20; children are more likely than
adults to get seriously ill
from the bacteria in raw milk.
• Consuming raw milk is not
worth the risk
Department of Food Science
Lecture 12: March 2, 2015
Safety Concerns over Raw Milk
• 13% of patients in raw milk outbreaks were hospitalized compared to 1 percent in pasteurized milk outbreaks.
• Raw milk outbreaks were all caused by bacteria, such as E. coli O157, which tend to produce more severe illnesses, according to the study.
• Pasteurized milk and cheese outbreaks were often caused by relatively mild infections like norovirus and Staphylococcus aureus.
• www.cdc.gov/eid ; http://www.cdc.gov/foodsafety/rawmilk/raw-milk-index.html.
Department of Food Science
Lecture 12: March 2, 2015
Spoilage Microorganisms in Foods
Food Spoilage Microorganisms: bacteria, yeasts, molds (yeasts and molds are fungi)
It is important to be able to distinguish food borne illness from food spoilage
Food borne illness occurs when food is eaten which looks normal, smells normal and tastes normal: you eat enough to make you ill from the ingested pathogens or toxins
Spoiled food may not normally cause food poisoning because it is rejected by the consumer before ingestion
Department of Food Science
Lecture 12: March 2, 2015
Microbial Food Spoilage = Changes in Food Quality
• Odor due to production of volatile end compounds
• Color pigment production or oxidation
• Texture softening due to the breakdown of pectin in
vegetables or the tissues by proteinases• Accumulation of gas
carbon dioxide, sulfur compounds • Slime formation
production of dextrans and/or amount of microorganisms
Department of Food Science
Lecture 12: March 2, 2015
Microbial foodborne illness
• Symptoms: Mild: abdominal pain, nausea, diarrhea,
vomiting Severe: spontaneous abortion hemolytic uremic syndrome
arthritis kidney failure and death
Department of Food Science
Lecture 12: March 2, 2015
Timeline of Foodborne Illness Best case: 6 daysWorst case: 23 days
http://ocw.jhsph.edu/courses/nutritionalhealthfoodproductionandenvironment/PDFs/FoodEnv-sec7f_Schwab_GrahamOCW.pdf
Department of Food Science
Lecture 12: March 2, 2015
Where from microorganisms come into foods?
CONTAMINATIONCONTAMINATION•Soil, contaminated water•Oral-fecal route
WASH HANDS AFTER VISITING
THE BATHROOM!!!!•Improper food handling
FOOD HANDLERS WHO ARE
UNWELL•Improper temperature of food storage•Improper cooking temperatures
Department of Food Science
Lecture 12: March 2, 2015
Harmful: Bacterial Pathogens of Public Health Concern
• Escherichia coli• Clostridium botulinum• Salmonella species• Campylobacter
species• Listeria species• Staphylococcus
aureus
• Aeromonas hydrophila
• Bacillus cereus• Shigella species• Vibrio spp. • Yersinia enterocolitica
http://vm.cfsan.fda.gov/~comm/ift-over.html
Department of Food Science
Lecture 12: March 2, 2015
Viruses in Foods
• Do not grow on foods
• When consumed in foods, they can multiply in the human body
• Cause food-borne illness
• Are smaller in size than bacteria
Department of Food Science
Lecture 12: March 2, 2015
Viruses in foods
• Norovirus: gastroenteritis or stomach flu Destroyed by cooking Water, salads, raw shellfish: potential carriers
• Hepatitis A Contagious viral disorder Inflammation of liver, jaundice, abdominal pain Contaminated water, shell fish Vaccine available
Department of Food Science
Lecture 12: March 2, 2015
Molds in Foods
• Grow on breads, cheese,
fruits• Produce toxins,
leading to food intoxication
If a food appears suspiciously moldy, simply discard it!If a food appears suspiciously moldy, simply discard it!
Moldy bread
Department of Food Science
Lecture 12: March 2, 2015
Parasites in foods
• Some are single-celled and tiny »Example: Toxoplasma
• Some are worms• Tape-wormscitihealth.com Flat-wormsanimalcorner.co.uk
Department of Food Science
Lecture 12: March 2, 2015
Prions in Foods sussex.ac.uk
• An infectious protein particleFolding of proteins
is abnormal
• Not a microorganism
Department of Food Science
Lecture 12: March 2, 2015
PRIONSIN
FOODS
• Prions are the cause of mad cow disease• BSE : Bovine Spongiform Encephalopathy• Caused by eating cow infected with this prion• Mood swings leading to dementia and death
Department of Food Science
Lecture 12: March 2, 2015
Prevention of Deleterious Microbes
Knowledge and ActionFood Handling and Food Processing
Department of Food Science
Lecture 12: March 2, 2015
Prevention of microbial illnesses of foods
• Prevent contamination
• Knowledge of how
contamination occurs
• Handle, store, prepare
foods safely
Department of Food Science
Lecture 12: March 2, 2015
Preventive measures for Outbreaks
• At the field Irrigation water Proximity to cattle, pig, and other animal ranches Farm worker access to portable toilets and hand
washing facilities
• At the processing plant Decontamination steps
• Distribution Maintaining appropriate temperatures
• Consumer education
Department of Food Science
Lecture 12: March 2, 2015
HACCP (hah- sup) Hazard Analysis of Critical Control Points
• A tool useful in the prevention of food safety hazards
• HACCP is not a stand alone program. • HACCP program also includes:
good manufacturing practices sanitation standard operating procedures personal hygiene program.
• A flow diagram of the complete process is important in conducting the hazard analysis.
Department of Food Science
Lecture 12: March 2, 2015
Principles of HACCP:
1. Hazard analysis
2. identify critical control points
3. establish critical limits
4. monitor critical control points
5. establish corrective action
6. Record- keeping
7. Verification
Department of Food Science
Lecture 12: March 2, 2015
HACCP: Summing up
• Not a standalone program
• Identifies critical control points
• Specific to a particular food service operation and establishment
• Continuous and systematic approach to assure food safety.
• Both FDA and USDA are proposing umbrella regulations which will require HACCP plans of industry.
Department of Food Science
Lecture 12: March 2, 2015
5 Major Risk Factors of Food Safety
1. Poor personal hygiene
2. Improper holding temperatures
3. Inadequate cooking: i.e. undercooking raw shell eggs
4. Contaminated equipment
5. Food from unsafe sources
Department of Food Science
Lecture 12: March 2, 2015
Fight Bac: Educating Consumers
www.fightbac.org
Department of Food Science
Lecture 12: March 2, 2015
Proper food storage starts at the store
• Shop for shelf-stable items such as canned and dry goods first
• Buy refrigerated and frozen foods and hot deli items last
• Don't choose meat, fish, poultry or dairy products that feel warm to the touch or have a damaged or torn package
• Place leaking packages in plastic bags• Choose only pasteurized dairy products• Choose only refrigerated eggs • Check "sell-by" and use by dates on packages• Buy intact cans that are not bulging, leaking or dented
on the seam or rimhttp://www.fmi.org/consumer/foodkeeper/general.htm
Department of Food Science
Lecture 12: March 2, 2015
REMEMBER!
Thawing :Frozen foods should be thawed in the refrigerator or microwave to ensure safety
Spoilage:
Both low and high temperatures are used to prevent food spoilage
Department of Food Science
Lecture 12: March 2, 2015
REMEMBER THE PRINCIPLE: FATTOM
• Food: medium for microorganism to grow
• Acidity: lower pH of food; prevents bacterial growth in foods
• Time: cook and store for recommended time
• Temperature: high temperature kills bacteria; low temperatures stop their growth
• Oxygen: packaging eliminates oxygen, so few or no bacteria
• Moisture: dry the food and prevent bacterial growth
Department of Food Science
Lecture 12: March 2, 2015
Methods of food preservation
• Heating to kill, slow and stop bacteria in foods:
1. Pasteurization: kills pathogenic bacteria, reduces number of microbes, but some bacteria survive; refrigeration storage needed heating the milk briefly to 161 °F for about 20
seconds, to kill disease-causing microbes (e.g., Salmonella, Escherichia coli O157,Campylobacter) that can be found in raw milk.
Department of Food Science
Lecture 12: March 2, 2015
Pasteurization
• Pasteurization does not significantly change the nutritional value of milk – pasteurized milk is rich in proteins, carbohydrates, and other nutrients.
• Heat slightly affects a few of the vitamins found in milk-- thiamine, vitamin B12, and vitamin C.
• Foods that can be pasteurized: eggs, milk, juices, spices, ice creams
Department of Food Science
Lecture 12: March 2, 2015
Methods of Food Preservation• Heating to kill, slow and stop bacteria in
foods: (examples: juices, milk, eggs)
2. Aseptic processing: sterilize food in a sterilized package using sterile process; longer shelf life than pasteurized foods; room temperature storage
3. Canning: Foods sealed into cans and then heated to a high temperature (above 100°C). Microbes in the food killed; sealed can prevents fresh contamination; Spores may survive
Department of Food Science
Lecture 12: March 2, 2015
Methods of food preservation
4. Irradiation: cold pasteurization Food exposed to x-rays, high-energy
electrons to kill microorganisms, insects, inactivate enzymes
Germination and ripening delayed Poultry, red meats, flour, spices, potatoes,
fruits, vegetables, grains can be irradiated Increases safety and shelf-life of foods Does not produce radioactive foods; no
potential risks
Department of Food Science
Lecture 12: March 2, 2015
Reducing the growth of microbes
• Many methods of food preservation are used.
• Processes such as fermentation, drying, pickling, all attempt to remove one or more of the factors necessary for the growth of food-spoiling microbes.
FATTOM