l12 microorganisms in foods

Department of Food Science

Lecture 12: March 4, 2013

Microorganisms in Foods

Lecture 12

March 4, 2013Dr. Ponnusamy



Food Microbiology

• The Beneficial Microorganisms….. Probiotics Prebiotics

• The Not-So-Beneficial Microorganisms.. Food borne Illness Food Spoilage Food borne pathogens



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



Let’s start with the GOOD bacteria……..



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.



Foods for Colon Health

• Probiotics: Live bacteria Improve intestinal microbial balance

• Yogurt – ‘live with active cultures’



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



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



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



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



ACTION OF PROBIOTICS



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.



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



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



Probiotics



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



The Not-So-Beneficial Microorganisms



The Not-So-Beneficial Microorganisms

• The ones that cause: Food borne Illnesses Food intoxications Food infections Food Poisoning Food Spoilage



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



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 ; Staphylococcus aureus



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.



• 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.



• 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.



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



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



Specific Product Concerns

• Produce

• Imported foods

• Juice

• Eggs

• Raw milk



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



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



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).



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



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



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.



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



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



Microbial foodborne illness

• Symptoms: Mild: abdominal pain, nausea, diarrhea,

vomiting Severe: spontaneous abortion hemolytic uremic syndrome

arthritis kidney failure and death



Timeline of Foodborne Illness Best case: 6 daysWorst case: 23 days

http://ocw.jhsph.edu/courses/nutritionalhealthfoodproductionandenvironment/PDFs/FoodEnv-sec7f_Schwab_GrahamOCW.pdf



Pathogens in Foods

• A pathogen is a microorganism capable of producing a disease

Bacteria

Viruses

MoldsPrions

Parasites



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



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



Viruses in Foods

• Do not grow on foods

• When consumed in foods, they can multiply in the human body

• Cause food-borne illness



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



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



Parasites in foods

• Some are single-celled and tiny »Example: Toxoplasma

• Some are worms• Tape-wormscitihealth.com Flat-wormsanimalcorner.co.uk



Prions in Foods sussex.ac.uk

• An infectious protein particleFolding of proteins

is abnormal

• Not a microorganism



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



Prevention of Deleterious Microbes

Knowledge and ActionFood Handling and Food Processing



Prevention of microbial illnesses of foods

• Prevent contamination

• Knowledge of how

contamination occurs

• Handle, store, prepare

foods safely



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



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.



Principles of HACCP: VIDEO

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



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.



Safe Food Storage and Preparation



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



Fight Bac: Educating Consumers

www.fightbac.org



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



SAFE FOOD HANDLING: VIDEO



REMEMBER!

Cooking:

www.foodsafety.gov



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



Take care: Guidelines for Leftovers



REMEMBER THE PRINCIPLE: FAT TOM

• 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



How to preserve foods

awakeandliving.com



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.



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



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



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



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.

FAT TOM



• Fermentation preserves & produces foods like

Cheese Yogurt Fermented

sausages

Wine & many more………..

l12 microorganisms in foods

Documents

illness food spoilage

food microbiology

foods lecture

probiotics human probiotics

probiotics prebiotics

colon health probiotics

probiotic yogurt

global probiotic market