1. Food Safety and toxicology

2. Aims
To explain the causes and effects of food poisoning and its relevance to food safety

3. Basically, food is a mixture of chemicals
Basically, food is a mixture of chemicals. Usually, food components are distinguished in four categories: 1.nutrients,
2. toxins of natural origin,
3. contaminants,
4. and additives.
The nutritients account for more than 99.9% of the food. The main classes of nutrients are :
carbohydrates, proteins, fats, vitamins, and minerals,
and all of them may pose toxicological risks to the consumer.

4. Food Borne diseases Poisoning Infections
Chemical poisoning intoxication enterotoxigenic invasive
poisonous poisonous microbial intoxications
Plant tissue animal tissue
Algae toxins mycotoxins bacterial toxins toxic metabolites
Enterotoxins neurotoxins interactions with carbohydrate
metabolism

5. What are Food-Borne Diseases?
People get sick with a food-borne disease when they consume foods or beverages contaminated with disease-causing microbes, chemicals, insects or other harmful substances.
Bacteria, viruses and parasites cause most of these diseases. Toxins, poisons and chemicals can also contaminate food and cause illness.

6. Harmful substances in foods
Food Safety
Harmful substances in foods
Pathogens
Bacteria, viruses, parasites
Some common pathogens causing foodborne illness
Staphylococcus aureus, Clostridium botulinum, Salmonella, Escherichia coli
Chemical contamination
Pesticides
Animal drugs
Pollutants
Natural toxins
Methyl mercury
Poisonous plants
Solanine

7. Perceived Risk from Food: % Viewing as a Serious Hazard

8. Major social impact of food borne disease…
Lost productivity time
Days work/school
Financial impact
Risk of mortality
Risk of transmission to family and others

9. The Food Pathogen Problem
Estimates of foodborne disease in U.S./yr:
6.5 to 33 MILLION foodborne illnesses
Up to 9,000 deaths
Hospitalization costs -- > $3 billion
Lost productivity -- > $9 billion
Under-reported!
Adapted from: Council for Agricultural Science and Technology. Foodborne Pathogens: Risks and Consequences, 1994.

10. FDAs Rank of Areas of Concern
Most Dangerous
Microbial food illness
Naturally occurring toxins in foods
Residues in foods
Environmental contaminants
Pesticides
Animal drugs, such as hormones, antibiotics
Food processing and nutrients in foods
Least Dangerous
Intentional Food Additives
Genetic modification of foods

11. Most food poisoning is caused by?
Bacteria

14. Microbes and Food Safety
Symptoms of foodborne illness
Diarrhea of more than 3 days’ duration
Fever of longer than 24 hours duration
Headache accompanied by muscle stiffness and fever
Numbness, muscle weakness, tingling sensations in the skin
Rapid heart rate, fainting, dizziness
Majority of food-poisoning cases
Result of errors consumers make in handling foods after purchase
Commercially prepared food is “usually” safe

15. Food Safety
Raw meats can contain live, disease-causing organisms
Thorough cooking makes them safe
In the mid-1990s a fast-food restaurant chain in the Northwest served undercooked hamburgers from meat contaminated with bacterium E. coli 0157:H7
4 people died
100s of patrons became seriously ill
As a result more Government Inspections and Industry controls were set up through the Hazard Analysis Critical Control Point (HACCP) plan

16. In order to grow and multiply germs need:
Warmth
Time
Moisture
Food
Remember it like this
Too
Many
Flies
Waiting

17. In ideal conditions where there is Moisture, Food and Warmth (37degrees centigrade is ideal), bacteria can double every 10 to 20 minutes. They do this by dividing in to two. This is called
Binary Fission

18. These cells are beginning to divide into two

19. Bacterial growth After 10 minutes After 20 minutes After 30 minutes

20. From 0 to 1,536,000 in only 80 minutes !!!!!! Time : 9.30 Bacteria : 0
cooking chicken to a core temperature of 75°C should kill most of the bacteria
Time : 9.30
Bacteria : 0
Time : 9.40
Bacteria : 12,000
Time : 9.50
Bacteria : 24,000
Knife contaminated by blood
Time :
Bacteria : 48,000
Time :
Bacteria : 96,000
Time :
Bacteria : 192,000
Time :
Bacteria : 384,000
Time :
Bacteria : 768,000
Time :
Bacteria : 1.5 million
From 0 to 1,536,000 in only 80 minutes !!!!!!

21. Bacterial Growth Curve
Numbers Of
Bacteria
Numbers of bacteria decrease
Stationary Phase
rapid multiplication
Numbers of bacteria remain constant as the number produced is equal to the number dying
no multiplication
Log Phase
Decline
Phase
Lag Phase
Time (hours)

22. Staphylococcus Aureus
Found in human nose and throat (also skin)
Clostridium Perfingens
Found in animals and birds
Salmonella
Found in animals, raw poultry and birds
Clostridium Botulinum
Found in the soil and associated with vegetables and meats
Bacillus Cereus Found in soil, vegetation, cereals and spices

23. Salmonella
Sources - The intestines of ill people and carriers, animals and animal food, raw meat, raw poultry, raw milk, raw eggs, food pests
Common food vehicles – Undercooked or contaminated cooked meat, raw milk and eggs
Onset period – 6 to 72 hours (usually 12 to 36) Endotoxin in intestine (infective food poisoning)

24. Salmonella
Symptoms - Abdominal pain, diarrhoea, vomiting and fever. Duration is usually one to seven days.
Specific characteristics – Usually requires millions of bacteria to cause illness. Multiplies from 5°C to 47°C under aerobic or anaerobic conditions.

25. Aerobic and Anaerobic
Bacteria which need oxygen to multiply are classed as aerobic
Bacteria which only multiply without oxygen are called anaerobic
Just to confuse you some bacteria including Salmonella, Staphylococcus aureus and Bacillus cereus are classed as facultative anaerobes which means they can multiply with or without oxygen!

26. Salmonella Specific controls Hygienic farm and abbatoir practices
Avoid cross contamination
Complete thawing of frozen poultry
Thorough cooking to 75°C for one minute
High standards of personal hygiene
Effective cleaning
Safe sewage disposal

27. Clostridium perfingens
Sources - The intestines of humans and animals, faeces and sewage, soil food pests, raw meat and poultry
Common food vehicles – Rolled joints, casseroles, stews, sauces and meat pies when cooking has removed oxygen
Onset period – 8 to 22 hours (usually 12 to 18) Enterotoxin in intestine. (infective food poisoning)

28. Clostridium perfingens
Symptoms - Abdominal pain, diarrhoea, (vomiting is rare) and fever. Duration is usually 12 to 48 hours.
Specific characteristics – Usually requires millions of bacteria to cause illness. Multiplies from 10°C to 52°C under anaerobic conditions. At 46°C it can double every 10 minutes. Produces spores. Illness caused from consuming millions of organisms

29. Staphylococcus Aureus
Sources - Human nose, mouth, skin, hands, spots, boils, septic cuts etc
Common food vehicles – Dairy products. Cold cooked meat and poultry, peeled cooked prawns
Onset period – 1 to 7 hours (usually 12 to 18) Exotoxin produced in food. (Toxic food poisoning)

30. Staphylococcus Aureus
Symptoms - Abdominal pain, diarrhoea, vomiting. Occasionally subnormal temperatures. Duration between 6 and 24 hours.
Specific characteristics – Usually requires millions of bacteria to cause illness. Toxin may survive boiling for up to 30 minutes. Multiplies from 7°C to 48°C under aerobic or anaerobic conditions. Can tolerate relatively high salt content.

31. Bacillus Cereus
Sources - Cereals, especially rice, cornflour, spices, dust and soil
Common food vehicles – Reheated rice, cornflour and spices.
Onset period – 1 to 5 hours. Exotoxin produced in food. (Toxic food poisoning)

32. Bacillus Cereus
Symptoms - Abdominal pain, diarrhoea, vomiting. Occasionally subnormal temperatures. Duration between 12 and 24 hours.
Specific characteristics – Forms spores which produce an exotoxin under aerobic or anaerobic conditions. Both the spores and toxin will survive normal cooking temperatures. Millions required to cause illness. Bacteria multiply between 7°C and 48°C.

33. Clostridium Botulinum
Sources - Fish intestine, soil and vegetables.
Common food vehicles – Low acid processed food contaminated after canning or vacuum packing. Smoked fish, bottled vegetables.
Onset period –2 hours to 5 days (usually 12 to 36 hours). A heat sensitive neurotoxin produced in the food which affects the nervous system. (Toxic food poisoning)

34. Clostridium Botulinum
Symptoms - Difficulties in swallowing, talking and breathing. Double vision and paralysis. Diarrhoea followed by constipation. Fatalities are common and survivors may take several months to recover.
Specific characteristics – Forms spores which produce an exotoxin under anaerobic conditions. Both the spores and toxin will survive normal cooking temperatures. Millions required to cause illness. Bacteria multiply between 3.3°C and 48°C.

35. Staphylococcus aureus
Pathogenic Bacteria
Source
Symptoms
Average Onset Time
Raw meat
Poultry and eggs
Pests and pets
Human and animal intestines
Dirt and refuse
Vomiting
Nausea
Diarrhoea
Abdominal pain
hours after eating
Salmonella
Human nose, throat, ears, skin
Septic wounds
Animals and raw milk
Vomiting
Abdominal pain
Low temperature
Staphylococcus aureus
1 – 7 hours after eating
Raw meat and poultry
Soil, dirt and refuse
Raw vegetables
Pests and pets
Human and animal intestines
Clostridium perfingens
Diarrhoea
Abdominal pain
hours after eating
Soil
Marine sediment
Raw fish and meat
Animal intestines
Paralysis
Breathing and swallowing difficulty
Diarrhoea followed by constipation
Clostridium botulinum
12 – 36 hours after eating
Nausea
Vomiting
Abdominal pain
Diarrhoea
1 - 5 hours or 8 –16 hours depending on the form of the food poisoning
Bacillus cereus
Dust and soil
Cereal, rice and pasta

36. Campylobacter enteritis
Escherichia Coli
0157
Listeriosis
That’s the end of lesson 1! Coming next lesson: Foodborne diseases
Typhoid and paratyphoid fever
Dysentery

37. Food Safety
Food can provide ideal conditions for bacteria to thrive or produce toxins
Disease-causing bacteria require
Warmth
40°F - 140°F = 4°C - 60°C
Moisture
Nutrients
To control bacteria
Keep hot food hot-above 140F
Keep cold food cold-below 40F/4C
Keep raw foods separate
Keep your hands and the kitchen clean

38. Food Safety Keep Hot Food Hot Keep Cold Food Cold
Keep cooked foods at 140°F or higher until served cooking does not destroy all bacterial toxins
If handled improperly can cause illness
Cooked foods should be refrigerated immediately or within two hours at the maximum
Keep Cold Food Cold
Start when you leave the grocery store
At home, put foods into the refrigerator or freezer immediately
When defrosting foods
Thaw meats or poultry in the refrigerator
Marinate meats in the refrigerator

39. Food with an “off” appearance or odor should not be used or tasted
Food Safety
Food with an “off” appearance or odor should not be used or tasted
Keep raw foods separate /Prevent cross-contamination
Raw foods, especially meats, eggs and seafood, are likely to contain bacteria
Keep the raw foods and their juices away from ready-to-eat foods
After handling raw foods wash surfaces & your hands, thoroughly with soap
Foods prone to microbial growth
Those high in moisture and nutrients
Those chopped or ground like meats and poultry

40. Foods That Make People Sick
Eggs
Raw, unpasteurized eggs are likely to be contaminated by Salmonella bacteria
Raw pasteurized egg substitutes may contain a few live bacteria
They may not be safe for pregnant women, the elderly, the very young, or those suffering from immune disorders
Raw Produce
Fruits and vegetables are a microbial threat unless they are thoroughly rinsed in running cold water
Ten years ago, meats, eggs, and seafood posed the greatest foodborne illness threat
Today produce equals them

41. Know the Potentially Hazardous Foods
Preparing and serving safe food is important to your customers.
Be careful when you work with and prepare foods that are “potentially hazardous.”
These are foods that have been linked to foodborne illness
Examples of potentially hazardous food are:
Meat, poultry and fish
Milk and egg products
Salads and sandwiches made with meat
Sliced melons and sprouts
Cooked vegetables, cooked rice or beans

42. You are responsible for identifying “potentially hazardous” foods.
Click below to reveal the “potentially hazardous” foods.
Potentially
Hazardous

43. Some People Face Special Risks Why Some People Face Special Risks
A variety of people may face these special risks:
Pregnant women
Very young children
People with chronic illnesses or weakened immune systems
Older adults
Why Some People Face Special Risks
A variety of people may face these special risks – pregnant women, young children, people with chronic illnesses or weakened immune systems, and older people.
Immune systems weaken with age. 43

44. Why Some People Face Special Risks (Continued)
Why Older Adults?
Immune systems weaken with age
Stomach acid decreases as you get older
Diseases/illnesses may further weaken the body
Why Some People Face Special Risks (Continued)
Stomach acid decreases as you get older. Stomach acid plays an important role in reducing the number of bacteria in our intestinal tracts – and the risk of illness.
Underlying illnesses such as diabetes, some cancer treatments, and kidney disease may increase a persons risk of foodborne illness. 44

45. Recognizing Foodborne Illness Recognizing Foodborne Illness
Can’t see, smell or taste bacteria in food
Often takes 1 to 3 days to cause illness, but can take up to 6 weeks
Recognizing Foodborne Illness
It is hard to tell if a food is unsafe, because you can’t see, smell or taste the bacteria it may contain.
Usually foodborne bacteria take 1 to 3 days to cause illness.
You could become sick anytime from 20 minutes to 6 weeks after eating some food with dangerous bacteria. It depends on a variety of factors, including the type of bacteria in the food.
Sometimes foodborne illness is confused with other types of illness. If you get foodborne illness, you might be sick to your stomach, vomit, or have diarrhea. Or, symptoms could be flu-like with a fever, headache, and body aches. The best thing to do is check with your doctor. 45

46. 3 Pathogens of Special Importance to Older Adults
Escherichia coli O157:H7
Salmonella
Listeria monocytogenes
Recognizing Foodborne Illness (Continued)
You could become sick anytime from 20 minutes to 6 weeks after eating some food with dangerous bacteria. It depends on a variety of factors, including the type of bacteria in the food.
Sometimes foodborne illness is confused with other types of illness. If you get foodborne illness, you might be sick to your stomach, vomit, or have diarrhea. Or, symptoms could be flu-like with a fever, headache, and body aches. The best thing to do is check with your doctor. 46

47. E. coli
Lives in intestines of healthy cattle and other ruminant animals.
Typical food sources:
Undercooked ground meats,
Contaminated produce served raw (lettuce, spinach, sprouts),
Unpasteurized milk 47

48. Salmonella Salmonella outbreaks have been associated with: Why eggs?
Raw and undercooked eggs
Undercooked poultry and meat
Raw milk
Produce and unpasteurized juice
Why eggs?
Salmonella can grow both inside the egg and on the outside of shells
NOTE: Consumption of undercooked eggs most common risky food behavior among persons > 60 years 48

49. Listeria Bacteria widespread in nature, soil, water
Survives and grows at refrigerator temperatures!
Risky Foods: Refrigerated Ready-to-Eat foods (i.e. deli salads, lunch meats, hot dogs, soft cheeses made with raw milk)
Listeria is associated with (RTE) refrigerated foods served without further heating
If contaminated, Listeria reproduces during long storage time of RTE meat and poultry products
Rarely causes disease in healthy non-pregnant persons 49

50. Listeria
Almost all cases: elderly, pregnant women and immune-compromised persons
Mild gastrointestinal symptoms: 8-48 hrs
Invasive illness: 2-6 weeks following exposure
Fever, muscle aches, headache, loss of balance, bacteremia, meningitis, encephalitis
20-30% death rate 50

51. Toxins
Some bacteria release poisons known as toxins which cause food poisoning. Some toxins, known as exotoxins multiply in food. These toxins are not easily destroyed by cooking and may remain in food once they have developed. Other bacteria produce toxins inside the human body only after the food has been eaten. These are called endotoxins

52. Moulds and Yeasts
Moulds are a type of fungi that will grow on most foods and at many temperatures. Some are used in food production such as cheese manufacture. Unwanted moulds usually spoil the food but do not cause food poisoning.
Yeasts are another type of fungi that will grow in food. They are used in making food such as bread and beer but also spoil many foods including jam, fruit juice, yoghurts and meats

53. Food Poisoning bacteria
Usually need millions of bacteria to cause illness.
The multiplication of bacteria within the food plays an important part in the disease

55. Spore Bacterial cell Spore forming inside cell
A resting resistant phase of some bacteria (including Clostridium Perfingens and Botulinum and Bacillus Cereus). The bacterium produces a protective coat which helps it to survive high temperatures (up to 120°C) and lack of water. When favourable conditions return, the spores split open and release the bacteria which are then able to grow and multiply
Bacterial cell
Spore forming inside cell

56. Spore Formation
This is what happens …………..
Cell

57. Spore forms in cell

58. Cell disintegrates

59. Spore is released

60. Spore starts to germinate

61. Spore continues to germinate

62. Now see as, in suitable conditions, the cell begins to divide (binary fission)………………………….

72. From raw materials to consumer:
Chemical, microbiological and technological aspects of food
Most of the food is treated in some way to improve its shelf life, texture, palatability
or appearance. It would be difficult to change this situation. So, it is important to know
what happens to the various food components on the way from raw material to consumer.

73. reduction and prevention of health risks hazardous reaction products
raw materials processing food quality and safety
reduction and prevention of health risks
hazardous reaction products
contaminants
Nutrients natural toxins contaminants
additives
Figure : Food: from raw material to consumer

74. the four categories of food components are discussed in the following order:
natural toxins (including microbial toxins)
2. antinutritives
3. contaminants,
4.food additives and the rationale for their use
5. nutrients.

75. Natural Toxin Endogenous toxins of plant origin
1 Toxic phenolic substances
Flavonoids
Tannins
Coumarin, safrole, and myristicin
2. Cyanogenic glycosides
Glucosinolate s
3 Natural contaminants
Mixing of edible plants with toxic plants
Contamination resulting from intake of toxic substances by animals
Contamination of milk with plant toxins
Natural toxins in aquatic organisms
4. Microbial toxins
Food-borne diseases
Bacterial toxins
Mycotoxins
Aflatoxins
Ochratoxin A

76. Antinutritives 3.1 Introduction
3.2 Type A antinutritives (antiproteins)
3.2.1 Protease inhibitors
3.3 Type B antinutritives (antiminerals)
3.3.1 Phytic acid
3.3.2 Oxalic acid
3.3.3 Glucosinolates
3.3.4 Dietary fiber
3.3.5 Gossypol
3.4 Type C antinutritives (antivitamins)
3.4.1 Ascorbic acid oxidase
3.4.2 Antithiamine factors
3.4.3 Antipyridoxine factors

77. Contaminants 4.1 Introduction 4.2 Contamination with heavy metals
4.2.1 Mercury
4.2.2 Lead
4.2.3 Cadmium
4.3 Nitrate
4.4 2,3,7,8-Tetrachlorodibenzo-p-dioxin
4.5 Pesticide residues
4.6 Food contaminants from packaging material

78. Food additives 5.1 Introduction
5.2 Use of food additives in relation to their safety
5.2.1 Colorings
5.2.2 Flavoring agents
5.2.3 Preservatives
Antioxidants
Antimicrobials
Antibrowning agents

79. Nutrients 6.2 Macronutrients 6.2.1 Fats
Undesirable fat components in raw materials
Changes in dietary fats during storage and
processing of raw materials, and during
manufacturing, preparation and storage of food
Rancidity
Oxidation of fats and oils, and
adverse health consequences
Effects of processing techniques on the
oxidation of dietary fats and oils
6.2.2 Carbohydrates
Changes in dietary carbohydrates during manufacturing
and storage of food
6.2.3 Proteins
Changes in proteins during processing of raw materials,
and during manufacturing, preparation and storage of food
6.2.4 Pyrolysis products occurring in food
6.3 Micronutrients
6.3.1 Hypervitaminoses
Vitamin A
Vitamin D

80. What is Food Hygiene? The science of preserving health
It involves all measures necessary to ensure the safety and wholesomeness of food during it’s preparation and storage

81. What does it involve? Rejecting contaminated food Decontaminating food
Protecting food from contamination through high standards of personal hygiene, cleaning and disinfection
Preventing any organisms multiplying
Destroying any harmful bacteria by thorough cooking
Discarding unfit or contaminated food

82. Food Poisoning
Normally associated with symptoms such as diarrhoea and vomiting
May also include headache, stomach cramps and fever
Bacteria are responsible for most cases
Other causes include mycotoxins (poisonous chemicals produced by some moulds)

83. Food Poisoning (contd.)
Physical contamination:- objects falling in to food – metal, glass, packaging materials etc.
Chemical contamination:- Bleach, cleaning chemicals getting in to food
Natural contamination: Poisonous plants and berries, undercooked red kidney beans

84. Poisonous mushrooms The deathcap – one bite can prove fatal
And also…..The deadly Puffer fish!