Food safety Training Course Co-financiado:. Microorganisms and food intoxications.

Food safetyTraining Course

Co-financiado:

Microorganisms and food intoxications

• What are they?• Main characteristics of living

beings?• Functions and applications?

Microorganisms

3| 32 Microorganisms and food Intoxications

• What do you understand by microbial growth?

• What factors affect microbial growth?

• How can we control the growth?

Microbial Growth


Microbial growing stages in a liquid environment. A – Lag stage; B- log stage; C- stationary stage and D- death stage

Log10células/mL

Tempo

crescimento em condiçõesóptimas

crescimento em outrascondições


Microbial Growth

Time

Growth in other situations

Growth in optimum conditions

• Intrinsic factors? • Extrinsic factors?• Other factors:

- Biological structures

- Natural antimicrobial substances


Microbial Growth

Data: Jay, J.M., 1996

Microbial growth


Microorganisms Minimum pH Optimum pH Maximum pH

Mold 1, 5 to 3,5 4, 5 to 6,8 8 to 11

Yeast 1, 5 to 3,5 4 to 6,5 8 to 8,5

Bacteria (most) 4,5 to 5,5 6,5 to 7,5 8,5 to 9

Lactic Bacteria 3 to 5 5,5 to 7,5 6,5 to 8

Table I – pH level interval for the growth of some microorganisms

Dados de : Jay, J.M., 1996

Microbial Growth


Product pH Product pH

Egg whites 7,5 to 9 Corn 7 to 7,5

Egg yolk 6,1 Potatoes 5,3 to 5,6

Shellfish 6,8 to 8,2 Carrots 5,2 to 6,2

Fish (most) 6,3 to 6,8 Onion 5,3 to 5,8

Fresh milk 6,3 to 6,5 Tomatoes 4,2 to 5,8

Butter 6,1 to 6,4 Oranges 3,6 to 4,3

Chicken 6,2 to 6,4 Grapes 3,4 to 4,5

Pork 5,3 to 6,4 Apples 2,9 to 3,3

Beef 5,1 to 6,2 Lemons 1,8 to 2,4

Table II - Approximate pH levels of some food products

• Extrinsic factorsMicrobial growth


TemperatureTemperature is one of the most relevant factors for microbial growth .

Microbial growth

Data: Jay, J., 1996.


Boiling point

Freezing

Hours N.º of bacteria

Microbial growth


•Utilization of risk temperatures while conserving food/meals;

•Utilization of inadequate temperatures while preparing/processing those foods (under processing);

These are the two main causes that lead to Intoxications :

Adapted from: Adams, M.R. and Moss, M.O., 1995


Microbial growth factors – Hurdle effect


• Main groups with importance for FS:– Bacteria

• Main characteristics

– Fungi (Molds and yeasts)• Main characteristics

Microorganisms

Bacteria

Photos: www.denniskunkel.com


• Unicellular (yeasts);• Multicellular (molds or filamentous

fungi);• Great decomposers of organic matter;• Widely used for making food and

beverages;• Some are eatable (mushrooms);• Responsible for deteriorating most

fruits and vegetables.

Fungi


Molds and yeasts

Some utilizations of fungi: a) Some eatable mushrooms. b) beer ; c) bread; d) Roquefort cheese with blue mold; e) e f) Camembert an brie cheeses (respectively) with white mold.


Molds and yeasts

Mold on food


• What are the sources of microorganisms that are present on foods?

– Soil;– Water; – Air;– Handlers;– Utensils and equipments;– Products themselves or raw

materials used in their fabrication.

Main sources


• Soil- Source of spore forming bacteria, fungi

and yeasts;- Addition of manure – faecal

microorganisms;- Dissemination of microorganisms:

wind, rain, animals, fertilization…

Main sources


Main sources What measures should be taken to avoid/reduce contamination?

Data: Jay, J.M., 1996 e Lacasse, D.. 1995.


Type of product Num. of microorganisms

TomatoNot washed > 1 000 000/ cm2

Washed 400-700/cm2

Collards

External leaves not washed 1 000 000 – 2 000 000/g

Internal leaves washed 200 000 – 500 000/g

Internal leaves 100 – 10 000/g

Table III – Effect of washing on the flora of vegetable products

• Water- May contain various types of

microorganisms (origin and level of pollution);

- Utilization of potable water!

How to avoid contamination?

Main sources


•Air- Non favourable environment for microbial growth;- Excellent conveyer of microorganisms from other sources: sneezing, coughing, agricultural activities …

How to reduce contamination caused by microorganisms transmitted by air?

Main sources


• Food

Diverse and proper flora :

– Vegetables– Animals

Main sources

Soil Water

Animals

Intestines


• Handlers- Diverse and own flora (faecal matter

and skin);- Main problems?

• Utensils and Equipments- Do not have own microflora;- Main cause of

CROSS CONTAMINATIONS!!!

Main sources


• What is “cross contamination”?Microorganisms present in raw foods, utensils and contaminated surfaces are transferred to prepared or washed foods or to clean surfaces..

- What are the main conveyers?- How to prevent/avoid?- Examples

Cross contamination


• Difference between “Hazard” and “Risk”

- What is the origin of hazards?

- Examples

Risks and hazards


Risks and hazards


Types of hazards

Microbiological

Examples of hazards Examples of associated foods Potential illnesses

Bacteria Salmonella Campylobacter

Eggs, poultry, raw milk and milk products

Raw milk, cheese, ice cream, salads

Salmonellosis Campylobacteriosis

Virus Rotavirus Hepatitis A virus

Salads, fruit and appetizers Fish, seafood, vegetables,

water, fruit, milk

Diarrhoea Hepatitis A

Parasites Toxoplasm Giardia

Pork, yearling lamb Water, salads

Toxoplasmosis Giardosis

Prions BSE agent Specific bovine risk materials

Variant of the Creutzfeldt-Jakob disease

Table IV – Classification of hazards related to food safety

Riscos e Perigos


Table V – Classification of hazards related to food safety

Types of hazardsChemical

Examples of hazards

Examples of associated foods

Potential illnesses

Natural toxins Aflotoxins Solanin Marine toxins

Nuts, corn, milk and milk products

Potato Shellfish, seafood

Cancer, congenital malformations, premature births, alterations of the immune system; nervous system degenerative diseases; hormonal alterations, dysfunction of various organs; fertility alterations; muscle and bone diseases; behaviour alterations.

Pollutants of industrial origin Mercury, Cadmium and lead

Dioxins, PCBs

Fish Fish, animal fat

Contaminants that result from food processing

Acrilamid Polycyclical

aromatic hydrocarbons

French fries, coffee, cookies, bread

Smoked products, vegetable oils, grilled food

Pesticides Insecticides, herbicides, fungicides

Vegetables, fruits and fruit products

Veterinary medicines Anabolics, antibiotics

Poultry, pork, beef

Non authorized additives Sudan I-IV, for red (dyes)

Sauces, spices

Material in contact with food Aluminium, tin, plastic

Canned or plastic packaged food

Other Cleaning products, lubrificants

Riscos e Perigos


Types of hazards

Examples of hazards

Examples of associated foods

Potential illnesses

Physical Bones, fish bones, glass, metal, stones

lesions

Nutritional Excess salt Table salt, snacks Cardiovascular diseases

Excess fat Butter, fat meat Obesity

Excess sugar Diabetes

Allergens Cow milk, peanut, eggs, crustaceans

Allergies

Table VI – Classification of hazards related to food safety

Intoxications and main agents


• What are the main factors that determine the occurrence of food intoxications?

• What are the main agents?• What are the symptoms and

characteristics of these illnesses?

• What are the main foods related to food intoxications?


Food Generally associated microorganisms

Raw seafood Vibrio sp., Hepatitis A virus, Norovirus (Norwalk-like viruses)

Raw eggs Salmonella

Undercooked meat Salmonella and Campylobacter, Escherichia coli STEC, Clostridium perfringens

Unpasteurized milk or juice

Salmonella, Campylobacter, Yersinia, STEC

Unpasteurized soft cheese

Salmonella, Campylobacter, Yersinia, Listeria sp., STEC

Homemade conserves Clostridium botulinum (botulism)

Hotdogs, ham, etc. Listeria sp.

Table VI – Food and agents generally associated to foodborne intoxications




Table VIII – Characteristics of main foodborne Intoxications

Microorganism Type of illness

Symptoms Probable food

Campylobacter jejuni InfectionDiarrhea, sometimes followed by fever; abdominal pain, nausea; headaches and muscle pain

Raw poultry and other food contaminated by raw poultry, unpasteurized milk, untreated water

Clostridium perfringes IntoxicationIntense abdominal cramps;

diarrheaMeat and meat products, sauces, products rich in protein

Escherichia coli (various types:

EPEC; EIEC; ETEC; and

EHEC)

Infection

Watery diarrhea, abdominal cramps, low fever, nausea, MAL ESTAR

Contaminated water, undercooked minced meat, unpasteurized milk and juice; pieces of melon.

Salmonella spp. Infection

Abdominal cramps, diarrhea, fever, headaches

Animal based food; other food contaminated due to the contact with feces, raw animal based food or infected handlers. Poultry, eggs, raw milk and meat are often found contaminated.

Hepatitis A InfectionFatigue, abdominal cramps, anorexia, intermittent nausea, diarrhea, vomiting

Raw or under cooked seafood, food prepared by infected handlers

*Bacillus cereus Poisoning

Watery diarrhea, crampsNausea and vomiting

Cooked products left uncovered; milk, meat, vegetables, fish; rice and food rich in starch.Cooked products left uncovered; milk, meat, vegetables, fish; rice and food rich in starch

Clostridium botulinum Poisoning

Lethargy, weakness, dizziness, double vision; difficulty talking, swallowing and/or breathing, paralysis, possible death

Inadequate processing of homemade conserves; hotdogs, marine products, canned minced garlic; honey

Staphylococcus aureus

Poisoning

Nausea, vomiting, abdominal cramps

Contaminated food due to inadequate handling and storage temperatures – meat and meat products; poultry and egg products; salads rich in proteins, sandwich fillings, pastry products with creams and fillings.

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Food safety Training Course Co-financiado:. Microorganisms and food intoxications.

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