FOOD ADDITIVES 4 TH YEAR LECTURE IST SEMESTER 1 FOURTH YEAR LECTURE Prof Kang'ethe

Introduction Protection from health and economic deception Individual 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 2 FOURTH YEAR LECTURE Prof Kang'ethe

Definition WHO/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 3 FOURTH YEAR LECTURE Prof Kang'ethe

Classification of additives Intentional and non intentional Non intentional – have no intended function become part of food in the phase of production or handling e.g pesticide, antibiotics, packaging materials & lubricants 4 FOURTH YEAR LECTURE Prof Kang'ethe

Why Food additives? Food production separated from areas of population concentration – preservatives Added 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 5 FOURTH YEAR LECTURE Prof Kang'ethe

Requirements for food additives Additive is safe in food at intended level Performs intended function Not used to deceive customer NOT cover faulty manufacturing practices Does not cause substantial reduction in food nutritional value Not used where GMP can achieve the same Method of analysis exists to police its use 6 FOURTH YEAR LECTURE Prof Kang'ethe

Preservatives Are antimicrobial and antioxidants Prevent microbial spoilage – sugar, salt, nitrates etc Sodium benzoates - active at pH mostly against yeast and moulds. Permitted level % Benzoic acid and its salts – against moulds and yeast 0.03=0.1% Sorbates – pH 6.5, moulds and yeasts % 7 FOURTH YEAR LECTURE Prof Kang'ethe

Preservatives Propionates – 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 8 FOURTH YEAR LECTURE Prof Kang'ethe

Additives Gas Sterilants Ethylene oxide gas above 10.7 o C, propylene oxide 35 o C. Used as fumigants Antibiotics Those not used in medicine. OTC and CTC used in fish (7ppm). Nicin used in cheese while subtilin,tylosin, nystatin and pimaracin against fungal. 9 FOURTH YEAR LECTURE Prof Kang'ethe

Additives Antioxidants Used to stabilize foods against oxidative deterioration. Natural occurring and synthetic. Butylated hydroxytoluene (BHT,) BHA, Propyl gallate, Lecithin and tocopherols Sequestrants Are stabilizers. React with metals hence synergists to antioxidants Surface active agents Play a role in growth processes of foods and assist metabolism converting them into sources of energy 10 FOURTH YEAR LECTURE Prof Kang'ethe

Naturally occurring lecithin, lanolin, bile salts, cholesterol. Stabilizers and thickners Used to give body and texture – agar agar, gelatin and cellulose. Mainly used in confectionery. Food colors – vary color of foods, Red G 11 FOURTH YEAR LECTURE Prof Kang'ethe

RESIDUES Non intentional Antibiotics and Pesticides Antibiotics Treatment or indiscriminate treatment of animal diseases. Failure to observe withdrawal periods. Problems of antibiotic residues Allergy to sensitized individuals Problem in manufacturing – milk 12 FOURTH YEAR LECTURE Prof Kang'ethe

RESIDUES Drug resistant strains Treatment drugs Carcinogens Milk – 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 13 FOURTH YEAR LECTURE Prof Kang'ethe

Microbiological Criteria Used to designate the foods safety These 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 14 FOURTH YEAR LECTURE Prof Kang'ethe

Microbiological Criteria Standard 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 15 FOURTH YEAR LECTURE Prof Kang'ethe

Microbiological Criteria – Sampling 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 16 FOURTH YEAR LECTURE Prof Kang'ethe

Microbiological Criteria-Sampling 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= 10 2 five units examined, no more than 2 exceed 10 2 n=5, c=2 m=10 2 ; M= units could exceed 10 2 but if any exceed 10 3 lot unacceptable Applied in conjunction with a comprehensive programm like HACCP. 17 FOURTH YEAR LECTURE Prof Kang'ethe