UGRC 145: FOOD AND NUTRITION IN EVERYDAY LIFE

Transcription

1 UGRC 145: FOOD AND NUTRITION IN EVERYDAY LIFE Session 7 Food Safety I Lecturer: PROF. MATILDA STEINER-ASIEDU, SBS, CBAS; University of Ghana, tillysteiner@gmail.com College of Education School of Continuing and Distance Education 2014/ /2017

2 Session Overview Learning Objectives: At the end of this lecture you should be able to: List agents that cause food borne illness Describe ways in which food borne microorganisms can cause illness in the body Explain the importance of food safety in nutrition and Health Describe how pesticides enter the food supply, and suggest possible actions to reduce consumption of residues Prof M. Steiner-Asiedu Slide 2

3 Session Outline The key topics to be covered in the session are as follows: Topic One: Food Safety and Hygiene-I Topic Two: Assignment/Discussion For Next Session Prof M. Steiner-Asiedu Slide 3

4 Topic One FOOD SAFETY AND HYGIENE-I Prof M. Steiner-Asiedu Slide 4

5 What is food safety? It is the practical certainty that illness or injury will not result from the consumption of food. It refers to ways in which food is handled, prepared and stored to avoid contamination and foodborne illnesses Prof M. Steiner-Asiedu Slide 5

6 Important definitions Foodborne illness illness of an infectious or toxic nature that is caused by the consumption of food or water. Food hazards biological, chemical or physical agents in food, or condition of food with the potential to cause an adverse health effect. What are some potentially harmful biological, chemical or physical agents that you can think of? Prof M. Steiner-Asiedu Slide 6

7 Biological Agents Biological agents are collectively referred to as microorganisms Microorganisms are minute organisms too small to observe without a microscope. Include bacteria, viruses and others. Occur naturally in the environment. Prof M. Steiner-Asiedu Slide 7

8 Biological Agents 80% of foodborne illnesses are caused by microorganisms. Microorganisms and parasites infect humans and cause specific diseases after being consumed in contaminated foods. Many pathogenic (disease causing) microorganisms are passed out of the body in faeces and infect another human beings when they reach the mouth through unwashed hands, utensils or flies Prof M. Steiner-Asiedu Slide 8

9 Biological agents Bacteria Viruses Moulds that produce toxins or poisons Parasites: mainly protozoa and helminthes (round and flat worms) Prof M. Steiner-Asiedu Slide 9

10 Bacteria and other biological agents Bacterial pathogens can grow in foods. Can multiply from low, possibly harmless levels to higher levels sufficient to cause illness in relatively short time. Viruses and parasites will multiply only in the cells of the infected individual but can survive in foods, and be transmitted by foods. Prof M. Steiner-Asiedu Slide 10

11 Chemical hazards Cleaning agents and lubricants that are used in food processing factories around the house Additives used in food processing for example to much of nitrites and nitrates added to sausages Pesticides and fungicides sprayed on crops in the farms Naturally occurring toxins or poisons in foods e.g. cyanogenic glycosides in cassava release cyanide Prof M. Steiner-Asiedu Slide 11

12 Physical agents stones plastic material glass pieces of bone hair strand I am sure you have all encountered some of these items in food. They can be dangerous, example stones can break a tooth. Prof M. Steiner-Asiedu Slide 12

13 Figure 1: Sources of food contamination Prof M. Steiner-Asiedu Slide 13

14 How do microorganisms in food cause illness? Microorganisms can cause foodborne illness in two waysby 1. Infection 2. Intoxication Prof M. Steiner-Asiedu Slide 14

15 Food Infection This results when food containing the pathogen (agent) is eaten. The pathogen grows and invades the host s tissue or release toxins in the host s intestines which initiate the illness. Prof M. Steiner-Asiedu Slide 15

16 Table 1: Sources and symptoms of illness from some foodborne infections Prof M. Steiner-Asiedu Slide 16

17 Food Intoxication Food-borne illness caused by the consumption of food containing a toxin already formed by the microorganism in the food before the food is eaten. Prof M. Steiner-Asiedu Slide 17

18 Table 2. Sources and symptoms of illness from some foodborne intoxications Prof M. Steiner-Asiedu Slide 18

19 Table 2. Sources and symptoms of illness from some foodborne intoxications Prof M. Steiner-Asiedu Slide 19

20 Food intoxication The most common cause of food intoxication is by the organisme Staphylococcus aureus bacterium. The most infamous organism is however Clostridium botulinum: an organism that produces a toxin so powerful that an amount as tiny as a grain of salt can kill several people within an hour. To reproduce and produce the toxin, Clostridium botulinum requires an atmosphere without air such as those found in improperly canned/bottled (especially home canned) foods. Botulinum toxin unlike staphylococcal toxin is easily destroyed by heat. Prof M. Steiner-Asiedu Slide 20

21 Dangerous symptoms of foodborne illness + Prof M. Steiner-Asiedu Slide 21

22 Food Safety: From farm to table Food safety must be applied at all levels of the food chain- farm to table. Careful food handling is required to prevent the effects of microrganisms: on the farm (food that is produced) in the processing factories during transportation to stores, restaurants etc during storage and cooking in the home. Cleanliness along the food chain is the major preventive measure to avoid disease from contaminated food. Prof M. Steiner-Asiedu Slide 22

23 Food Safety: From farm to table Prof M. Steiner-Asiedu Slide 23

24 Topic Two ASSIGNMENT/DISCUSSION FOR NEXT SESSION Prof M. Steiner-Asiedu Slide 24

25 Take home What are the physical agents in food that can cause health problems List some of the problems that may arise when one eats food that is not safe Prof M. Steiner-Asiedu Slide 25

26 Next week We shall continue with food Safety Part II. Make sure you go over handout 5A & 5B before the next lecture. Prof M. Steiner-Asiedu Slide 26