Food Safety Training Course Co-financiado:

Microorganisms and food

5| 25 Microorganisms and food What are they? Main characteristics of living beings? Functions and applications? Microorganisms

4| 25 Microorganisms and food What do you understand by microbial growth? What factors affect microbial growth? How can we control the growth? Microbial Growth

5| 25 Microorganisms and food Microbial growing stages in a liquid environment. A – Lag stage; B- log stage; C- stationary stage and D- death stage Microbial Growth Time Growth in other situations Growth in optimum conditions

Intrinsic factors - Nutrients - pH - Water activity - Available oxygen Extrinsic factors - Temperature - Relative humidity - Atmospheric oxygen Other factors: - Biological structures - Natural antimicrobial substances Microbial growth factors 6| 25 Microorganisms and food

Temperature Temperature is one of the most relevant factors for microbial growth. 7| 25 Microorganisms and food Microbial growth factors - Temperature

Main cause that lead to Intoxications : Utilization of risk temperatures while conserving food/meals; Utilization of inadequate temperatures while preparing/processing those foods (under processing); 8| 25 Microorganisms and food Microbial growth factors - Temperature

Adapted from: Adams, M.R. and Moss, M.O., | 25 Microorganisms and food Microbial growth factors – Hurdle effect

Main groups with importance for FS: –Bacteria Main characteristics –Fungi (Molds and yeasts) Main characteristics Microorganisms 10| 25 Microorganisms and food

Unicellular; Various forms (cocci, bacilli, spirilla); Some develop resistant structures (spores); Main cause of food intoxications of biological origin. Bacteria 11| 25 Microorganisms and food

Bacteria Photos: 12| 25 Microorganisms and food

Fungi (molds and yeasts) 13| 25 Microorganisms and food 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.

14| 25 Microorganisms and food 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.

15| 25 Microorganisms and food Molds and yeasts Mold on food

16| 25 Microorganisms and 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

17| 25 Microorganisms and food Soil -Source of spore forming bacteria, fungi and yeasts; -Addition of manure – faecal microorganisms; -Dissemination of microorganisms: wind, rain, animals, fertilization… Main sources

18| 25 Microorganisms and food Main sources What measures should be taken to avoid/reduce contamination? Data: Jay, J.M., 1996 e Lacasse, D Type of product Num. of microorganisms Tomato Not washed> / cm2 Washed /cm2 Collards External leaves not washed – /g Internal leaves washed – /g Internal leaves100 – /g Table I – Effect of washing on the flora of vegetable products

19| 25 Microorganisms and food Water - May contain various types of microorganisms (origin and level of pollution); - Utilization of potable water! How to avoid contamination? Main sources

20| 25 Microorganisms and food 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

21| 25 Microorganisms and food Food Diverse and proper flora : –Vegetables –Animals Main sources SoilWater Animals Intestines

22| 25 Microorganisms and food 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

23| 25 Microorganisms and food 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

24| 25 Microorganisms and food Difference between “Hazard” and “Risk” - What is the origin of hazards? - Examples Risks and hazards

Riscos e Perigos 25| 25 Microorganisms and food Types of hazardsExamples of hazardsExamples of associated foodsPotential illnesses SalmonellaEggs, poultry, raw milk and milk products Salmonellosis Hepatitis A virusFish, seafood, vegetables, water, fruit, milk Hepatitis A Bones, fish bones, glass, metal, stones Lesions AflotoxinsNuts, corn, milk and milk products Cancer, malformations, alterations of the nervous system diseases; hormonal alterations… DioxinsFish, animal fat Table II – Classification of hazards related to food safety