food additives
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FOOD ADDITIVES. 4 TH YEAR LECTURE IST SEMESTER. Introduction. Protection from health and economic deception Individual consumers unable to protect themselves hence responsibility rests on industry and Government - PowerPoint PPT PresentationTRANSCRIPT
FOOD ADDITIVESFOOD ADDITIVES4TH YEAR LECTURE
IST SEMESTER
1FOURTH YEAR LECTURE Prof Kang'ethe
IntroductionIntroductionProtection from health and
economic deceptionIndividual consumers unable to
protect themselves hence responsibility rests on industry and Government
Time when adding chemicals to food not necessary but prehistoric man added when he smoked food
2FOURTH YEAR LECTURE Prof Kang'ethe
DefinitionDefinitionWHO/FAO – non nutritious substances
added intentionally, in small quantities to improve appearance, flavor, texture and storage properties. Failed to include nutritional supplements and non intentional additives
Codex alimentarius – any substance, including those of microbial origin not normally eaten as food stuff proper but use causes substance or metabolites become constituent of food proper
3FOURTH YEAR LECTURE Prof Kang'ethe
Classification of additivesClassification of additivesIntentional and non intentionalNon intentional – have no
intended function become part of food in the phase of production or handling e.g pesticide, antibiotics, packaging materials & lubricants
4FOURTH YEAR LECTURE Prof Kang'ethe
Why Food additives?Why Food additives?Food production separated from areas of
population concentration – preservativesAdded for functional properties – color,
flavor, texture, nutritional supplements etc
Convenience foods – foods whose preparation labor removed from household to processor or manufacturer. eg flour, can of beans or soups, cake mix, githeri, chapos, pisas, etc
5FOURTH YEAR LECTURE Prof Kang'ethe
Requirements for food Requirements for food additivesadditivesAdditive is safe in food at intended levelPerforms intended functionNot used to deceive customerNOT cover faulty manufacturing practicesDoes not cause substantial reduction in
food nutritional valueNot used where GMP can achieve the
sameMethod of analysis exists to police its use
6FOURTH YEAR LECTURE Prof Kang'ethe
PreservativesPreservativesAre antimicrobial and antioxidantsPrevent microbial spoilage – sugar,
salt, nitrates etcSodium benzoates - active at pH 2.5-
4.0 mostly against yeast and moulds. Permitted level 0.2 -1.25%
Benzoic acid and its salts – against moulds and yeast 0.03=0.1%
Sorbates – pH 6.5, moulds and yeasts 0.03 -0.1%
7FOURTH YEAR LECTURE Prof Kang'ethe
PreservativesPreservativesPropionates – pH 5.0 – 6.0, used in
baked foods mainly against moulds and rope (B. mesentericus)
Sulphur dioxide and sulfites – Fruits pulp juices. Prevent enzymic and non enzymic browning. Preserve vit C, destroy thiamin, limits 500ppm
Acetates – Act in low pH foods –moulds and yeast
8FOURTH YEAR LECTURE Prof Kang'ethe
AdditivesAdditivesGas SterilantsEthylene oxide gas above 10.7oC,
propylene oxide 35oC. Used as fumigants
• AntibioticsThose not used in medicine. OTC and
CTC used in fish (7ppm). Nicin used in cheese while subtilin ,tylosin, nystatin and pimaracin against fungal.
9FOURTH YEAR LECTURE Prof Kang'ethe
AdditivesAdditivesAntioxidantsUsed to stabilize foods against oxidative
deterioration. Natural occurring and synthetic. Butylated hydroxytoluene (BHT,) BHA, Propyl gallate, Lecithin and tocopherols
• SequestrantsAre stabilizers. React with metals hence
synergists to antioxidantsSurface active agentsPlay a role in growth processes of foods and
assist metabolism converting them into sources of energy
10FOURTH YEAR LECTURE Prof Kang'ethe
Naturally occurring lecithin, lanolin, bile salts, cholesterol.
Stabilizers and thicknersUsed to give body and texture –
agar agar, gelatin and cellulose. Mainly used in confectionery.
• Food colors – vary color of foods, Red G
11FOURTH YEAR LECTURE Prof Kang'ethe
RESIDUESRESIDUESNon intentionalAntibiotics and PesticidesAntibioticsTreatment or indiscriminate
treatment of animal diseases. Failure to observe withdrawal periods.
Problems of antibiotic residuesAllergy to sensitized individualsProblem in manufacturing – milk
12FOURTH YEAR LECTURE Prof Kang'ethe
RESIDUESRESIDUESDrug resistant strainsTreatment drugsCarcinogensMilk – 13% in milk from rural and
urban Nakuru and Kiambu, 1% in urban milk in Dagoretti, Nairobi mostly penicillin type
Pesticides in milk, meat, eggs and human milk – agricultural activities. Poor handling procedures – non target hence affect environment
13FOURTH YEAR LECTURE Prof Kang'ethe
Microbiological CriteriaMicrobiological CriteriaUsed to designate the foods safetyThese fall into two categories –
mandatory and advisory.Mandatory usually contains limits for
pathogens of public health importance. Limits for non pathogens may also be set.
Advisory is a microbiological end product specification intended to increase assurance that guidelines have been met
14FOURTH YEAR LECTURE Prof Kang'ethe
Microbiological CriteriaMicrobiological CriteriaStandard is considered part of a law
that has regulatory enforcement by agency having jurisdiction (KEBS)
Criterion consists of statement of microorganism of concern, analytical methods for detection and quantification, sampling plan when and where samples can be taken, limits considered appropriate and number of units that should confirm
15FOURTH YEAR LECTURE Prof Kang'ethe
Microbiological Criteria – Microbiological Criteria – Sampling PlansSampling Plans
Criteria for acceptance based on appropriate examination of number of samples units by specified methods
Two class plan and three class plan◦Two class consists of n, c and m. ◦n is the number of units that must be
examined◦c is the maximum acceptable number
that may exceed the criterion◦m is maximum number or level above
this either marginally acceptable or unacceptable
16FOURTH YEAR LECTURE Prof Kang'ethe
Microbiological Criteria-Microbiological Criteria-Sampling plansSampling plans
Class three criterion has all the three levels in class two plus M
M is a quantity used to separate marginally acceptable from unacceptable quality foods
n=5, c = 0, 2 and m= 102 five units examined, no more than 2 exceed 102
n=5, c=2 m=102; M= 103 2 units could exceed 102 but if any exceed 103 lot unacceptable
Applied in conjunction with a comprehensive programm like HACCP.
17FOURTH YEAR LECTURE Prof Kang'ethe