food safety and hygiene

1. Food safety
By
Dr Utpal Sharma
Assistant Professor
Department of Community Medicine
SMIMS, Gangtok, Sikkim

2. Introduction
Food is the most important item to sustain life on
this planet, next only to oxygen
However it is a potent source of pathogens,
toxins and disease.
Food is liable to contamination, at any point
during its journey from the producer to the
consumer.
Human consumes 30 tons of food during his
lifetime….????

3. What is food hygiene….?????
 Food hygiene, in its widest sense, implies hygiene in
the production, handling, distribution and serving of all
types of food.
 The primary aim of food hygiene is to prevent food
poisoning and other food-borne illnesses.
 The importance of surveillance of food-borne diseases
has been underlined in the WHO Sixth General
Program of Work .
 The most important international program carrying out
activities in the field of food hygiene is the Joint
FAO/WHO food Standards Program

4. Food hygiene is more than
cleanliness .....
1. Protecting food from risk of contamination,
including harmful bacteria, poison and other
foreign bodies.
2. Preventing any bacteria present multiplying to an
extent which would result in the illness of
consumers or the early spoilage of the food.
3. Destroying any harmful bacteria in the food by
thorough cooking or processing.
4. Discarding unfit or contaminated food.

5. What if food hygiene compromised…???
1. Food poisoning outbreaks and sometimes death
2. Food contamination, customer complaints and brand
image
3. Pest infestations
4. Waste food due to spoilage
5. The closure of food premises
6. Fines and costs of legal action taken because of
contraventions in hygiene legislation, or because of
the sale of unfit or unsatisfactory food.
7. Civil action taken by food poisoning suffers
8. Loss of production and food which has to be destroyed
9. Decontamination cleaning and replacement of
damaged equipment.

6. Classification of Food – borne Illnesses
Bacterial diseases (infections &
intoxications)
Typoid fever, paratyphoid fever,
Salmonellosis, Staphyloccal
intoxication,
Cl. perfringens illness Botulism
b. cereus Food Poisoning
e. coli diarrhoea
non-cholera vibrio illness
V. parahaemolyticus - infection,
streptococcal infection, Shigellosis,
Brucellosis
Viral diseases Viral hepatitis, Gastroenteritis
Parasites Taeniasis, Hydatidosis, Trichinosis,
Ascariasis, Amoebiasis, Oxyuriasis

7. Classification of Food – borne Illnesses
Chemical poisons Pesticides, heavy metals
(arsenic, lead, cadmium,
etc.)
Food toxins Lathyrism, Epidemic dropsy,
Aflatoxins , Endemic
ascities, Fusarium toxins

8. Food borne pathogen and associated
diseases

9. Milk hygiene
Milk is an efficient vehicle for a great variety
of disease agents.
 The sources of infection or contamination of
milk may be
The dairy animal
Human handler or
The environment, e.g., contaminated vessels,
polluted water, flies, dust, etc.
The milk hygiene begins at its source of
production namely the dairy farm.

10. Diseases conveyed through milk
Disease Organism Reservoir/Source
Tuberculosis M tuberculosis (bovine) Cattle
Brucellosis B abortus / melitensis Cattle, Goat
Q Fever Coxiella burnetti Cattle
Septic Sore throat Streptococcus pyogenes Cattle, milk handlers
Food Poisoning Staphylococcus aureus Cattle, milk handlers
Diarrhoea and
dysenteries
Shigella, E histolytica Milk handlers
Cholera Vibrio cholerae Water, milk
Enteric fever Salmonella species Milk
Viral hepatitis, polio
Hepatitis A,
Polio viruses Milk
Diphtheria Corynebacterium
diphtheriae
Milk

11. Clean and safe milk
 The safety and keeping quality of milk are related to its
microbial content.
 The first is a healthy and clean animal.
 Milk from a healthy udder contains only a few
organisms, and these are relatively unimportant.
 Secondly, the premises where the animal is housed
and milked should be sanitary.
 The milk vessels must be sterile and kept covered.
The water supply must be bacteriologicaly safe.

12. Cont…
Milk handler must be free from communicable
diseases, and before milking they must wash their
hands and arms.
Where possible, milking machines must be used.
A periodical medical examination of personnel and
the all other logistic is recommended.
Milk should be cooled immediately to below 10°C
after it is drawn to retard bacterial growth.
In the production of good quality milk, cleanliness
of all containers and equipment in which milk is
handled is very important.

13. What kind of milk is
acceptable…???
Milk only without the microbial contamination is
acceptable of consumption purpose.
Methylene blue test
This is done in order to detect microorganisms in
milk
The test is carried out in the milk accepted for
pasteurization
Based on the fact that there is a decrease in
colour imparted to the milk if it is contaminated
with bacteria.

14. Methylene blue test…
 The sample of milk retaining blue color for the longest
duration us considered to be of best quality
 It is because the sample requiring shortest time will be
having more microorganisms to reduce methylene
blue
The sample is held at 37°C till the colour dissapear
Definite quantity of methylene blue is added to 10 ml of milk
Inference

15. Pasteurization of milk
 Boiling kills the microorganisms but affects the quality,
taste and flavour of milk, as constituents are heat-labile
 Pasteurization involves rapidly heating milk (< the
boiling point), maintaining it uniformly over a definite
period and rapidly cooling it.
 This destroys most and of the pathogenic
microorganisms, reduces the total quantity of all the
microorganisms without affecting its inherent qualities
(taste and flavour)
 It may not sterilize milk but makes it non-infective,
retains its nutritive and aesthetic qualities and improves
its keeping quality.
 Milk is kept at 63-66°C for at least 30 minutes, and then
quickly cooled to 5°C.

16. Methods of Pasteurization
Holder (Vat) method :
 Milk is heated to the temperatures between 63ºC and 65.5º C
 Held in large tanks at that temperature for 30 min
 rapidly cooled to 5°C.
High Temperature Short Time (HTST) Method
 Milk is heated to 72°C
 Helt at same temperature for15 seconds and then rapidly
cooled to 4ºC.
Utra High Temperature Method (UHT Method)
 Milk is rapidly heated usually in 2 stages (the second stage
usually being under pressure) to between 125°C, for a few
seconds only.
 It is then rapidly cooled and bottled as quickly as possible.

17. Tests of pasteurized milk
Phosphatase Test :
 Based on the fact that the enzyme phosphatase is destroyed by the
pasteurization temperatures; but not at a lower temperature
 The test is performed by addition of disodium phenyl-phosphate to
pasteurized milk.
 The enzyme phosphatase, if present, splits up the giving different
shades of blue colour depending upon the amount enzyme present.
 The colour is matched against the standard colours in a Lovibond
colorimeter. (Standard is < 2.3 Lovibond units)
Standard plate count
 A limit of 30,000bacterial count per ml is the standard in most of
the countries
Coliform count
 Absence of coliform in 1 ml of milk is accepted as properly
pasteurized milk

18. Food jargons…..!!!
Food Processing
 Food processing is the technique used to transform raw
ingredients into food or to transform food into other forms for
consumption e.g baking steaming etc.
Food Additives
 Non-nutritious substances added intentionally to food,
generally in small quantity, to improve the basic properties of
food like its appearance, flavour, texture e.g colouring agents
Food Fortification
 Food Fortification is the whereby nutrients are added to foods
in relatively small quantities to maintain or improve the quality
of diet of a group, a community, or a population e.g iodized
salt

19. Food toxicants
Neurolathyrism
A neurodegenerative disease that is
caused by heavy consumption of grass
pea, Lathyrus sativus.
Active neurotoxin is called
-oxalyl amino alanine (BOAA)
Upper motor neuron disorder
with symmetrical spastic paralysis.
Sensation and sphincters are
spared.

20. Cont….
 Most commonly seen in men in the age group 15-45 years
 Onset is sudden, often preceded by exertion or exposure to
cold.
 A patient may find himself paralyzed on getting up in the
morning.
 Sometimes backache and stiffness of legs precede the
paralysis of legs.
 The patient may pass through progressive stages of severity
 Latent stage
 No-stick stage
 On-stick stage
 Two-stick stage
 Crawler stage
Interventions
Vit C prophylaxis Steeping
Banning the crop Education
Parboiling
Genetic approach

21. Cont…..
Aflatoxin
 The first known outbreak of Aflatoxicosis probably occurred in
England in 1960, among young turkeys fed on infested groundnut.
Causative Agent :
 Aspergillus flavus and Aspergillus parasiticus
 affects foods in poor storage conditions of high temperature (30-
37°C),high humidity, as is common in the rainy season and during
floods and cyclones.
 The fungus Infests improperly stored foods like maize, groundnut,
soya, sorghum, rice, wheat, sunflower, tree nuts, spices and even
milk and cheese.
Toxins :
 Aflatoxin B1 is the most potent known natural hepatocarcinogen.
 They are known to cause hepatitis (jaundice), ascitis, portal
 hypertension, liver cirrhosis and hepatocellular carcinoma.

22. Cont…..
Ergot (Claviceps fusiformis &Claviceps
purpurae)
 It is a field fungus
 Infests foodgrains like bajra, sorghum and wheat during the
flowering stage.
 fungus grows as a blackish mass and imparts black colour to
the seed
 Symptoms are acute but rarely fatal
 Includes nausea, vomiting, abdominal cramps and drowsiness
for 24-48 hours after ingestion
 In chronic cases painful cramps in limbs along with peripheral
gangrene due to vasoconstriction could be seen (St.
Anthony’s fire in France in the 11th century)
Prevention
 Infested grains can be easily removed by
floating them in 20% salt water
 Upper limit is 0.05 mg per 100 gm of
food material

23. Cont….
Epidemic dropsy
 The active agent is sanguinarine, and the cause is
contamination of mustard oil with argemone oil.
 Symptoms included
 Sudden non-inflammatory, bilateral swelling of the legs associated with
diarrhoea
 In advanced stage patient gets dyspnoea and signs of congestive
cardiac failure (CCF)
 If not treated death may ensue, mortality rate of 5-50% has been
reported.
Tests to detect argemone oil contamination
 Nitric acid test ( positive when argemone oil is 0.25%)
 Paper chramatography (Detect upto a concentration of 0.0001%)
Prevention
 Removing the weeds of argemone after harvest
 Strict enforcement of PFA

24. Cont….
Endemic ascitis
 Causitive agent is hepatotoxin pyrrolizidine alkaloid found in
Crotalaria (jhunjhunia) seeds
 Symptoms comprises of ascities and jaundice
 Both sexes in all age group, except infants are affected
 Overall mortality is about 40%.
Prevention
 Educating people
 Deweeding jhunjhunia plants
 Sieving of millets at household level.

25. Cont…
Fusarium toxins
 It is another field fungus affecting crops like sorghum, rice and
maize.
 seen in the subtropical and temperate regions.
 The fungus produces toxins like deoxynivalenol and
fumonisin
 Symptoms includes vomiting and diarrhoea.
Detection of Mycotoxins :
 Many sophisticated methods are available for the detection of
Mycotoxins.
 Thin Layer Chromatography (TLC),
 Radio-immuno Assay (RIA) and
 ELISA tests are available.

26. Thank you folks ….be
safe