Spoilage of food and fermented food products
- 1. SUBJECT INCHARGE DR.R.DINESH KUMAR SUBMITTED BY : ASSISTANT PROFESSOR KOWSALYA M.S DEPARTMENT OF MICROBIOLOGY III – BSC (MICROBIOLOGY ) VIAAS SANKAGIRI DEPARTMENT OF MICROBIOLOGY VIAAS SANKAGIRI. • VIVEKANANDHA ARTS AND SCIENCE COLLEGE FOR WOMEN VEERACHIPALAYAM-637303,SANKAGIRI,SALEM DT.,TAMIL NADU INDIA. AFFILIATED TO PERIYAR UNIVERSITY, SALEM ; RECOGNISED UNDER SECTION 2(F) & 12(B) OF THE UGC ACT, 1956 ) DEPARTMENT OF MICROBIOLOGY . SUBJECT : FOOD MICROBIOLOGY TOPIC : SPOILAGE OF FOOD AND . FERMENTED FOOD PRODUCTS
- 2. SPOILAGE OF FOOD AND FERMENTED FOOD PRODUCTS
- 3. CONTENT • What is fermentation • What is spoilage • Properties of fermented food • Detection of microbiological spoilage • Major cause of deterioration Groups of microorganisms involved in Spoilage • Microbiological food spoilage mechanism • Spoilage of fermented food and beverages • Spoilage of wine • Spoilage of beer • Spoilage of cider
- 4. • Spoilage of Sauerkraut • Spoilage of Pickle • Spoilage of Cheese • Spoilage of yogurt • Safety of fermented foods • Control of microbiological Spoilage
- 5. What is Fermentation? Conversion of sugar into Alcohol In aerobic condition.
- 6. WHAT IS SPOILAGE ??? Characteristics change in flavour is so that is no longer acceptable for consumption.
- 7. PROPERTIES OF FERMENTED FOOD • Enhanced preservation • Enhanced nutritional value • Enhanced functionality • Enhanced organoleptic properties • Unique • Increased economic value
- 8. DETECTION OF MICROBIOLOGICAL SPOILAGE Organoleptic Methods for Spoilage Detection Odour • Production of volatile metabolites by microorganisms that are detectable by odour. • Foul-smelling amines are often produced during proteolysis Fruity and alcoholic can be produced by sugar catabolism. Visual • Ropy baked goods – stringy, mucilaginous appearance when the . Crumb is pulled apart. • Fermentation of high sugar products-visible bubbling of the Product from gas produced or by expansion of the hermetically sealed packages.
- 9. Taste • In fruit juices, yeast spoilage produced a buttery taste caused by diacetyl. • A phenolic – tasting compound, guiaicol, is produced when Alicyelobacillus grows in fruit juices. • Sour tastes are produced in diary, meat, and vegetables product after extensive acid production by lactic acid bacteria. Microbiological Methods of Spoilage Detection • Performed during research and development of food products in order to establish and optimize a product’s shelf life and, as part of quality assurance programs during commercial production, to verify that the anticipated shelf life can be attained.
- 10. MAJOR CAUSE OF FOOD DETERIORATION • Growth and activities of microorganisms (bacteria, yeats, and mold ) • Activities of food enzymes and other chemical reactions within the food itself • Infestation by insects ( parasites and rodents ) • Inappropriate temperature for a given food • Either the gain or loss of mositure • Reaction with oxygen • Exposure to light • Physical stress
- 11. GROUPS OF MICROORGANISMS INVOLVED IN SPOILAGE • Molds : penicillium, Aspergillus, Rhizopus, Mucor, Fusarium, Alternaria, Cladosporium, Eurotium, and Byssochlamys. • Yeast : fermentative and oxidative yeast • Pseudomonadaceae • Enerobacteriaceae : Escherichia, Erwinia, Enterobacter, Citrobacter, Serratia, and Proteus • Lactic acid bacteria : Lactococcus, Leuconostoc, Enterococcus, and Pediococcus • Coryneforms : Corynebacterium (facultatively anaerobic) and Brevibacterium (aerobic)
- 12. MICROBIOLOGICAL FOOD SPOILAGE MECHANISM • Sugar fermentation with acid production • Sugar fermentation with gas production. • Protein hydrolysis (bacteria produced proteolytic enzymes that hydrolyzed proteins in foods) • Digestion of complex carbohydrates (Amylolytic enzymes produced by molds and bacteria digest starches to polysaccharides and simple sugars, which destroys the viscosity of products in which starches are used as thickening agents) • Lipolysis (pseudomonas, molds, and staphylococcus, produced lipolytic . enzymes that hydrolyzed lipids, producing readily oxidizable substances that have a rancid odour)
- 13. • Oxidaodour) of organic acids and alcohols ( molds and oxidative yeasts can grow on acidiied foods and metabolize the organic acid. Thus the PH of the food raises to levels high enough to permit the growth of other types of spoilage organisms) • Guaiacol production (Alicyclobacilli can grow in some fruit or vegetable juices, metabolizing vancillin and other precursor molecules to guaiacol, a product with an asphalt – like or phenolic odor) • Surface growth ( by growing on the surface. It is caused simply by the accumulation of very high numbers of microbial cells )
- 14. SPOILAGE OF FERMENTED FOOD AND BEVERAGES Despite the low PH or ethanol content of fermented food and beverage products, which prohibit the growth of pathogens, spoilage CAN still OCCUR. For this reason, fermentation are frequently combined with other processes such as soaking, washing, cooking and Pasteurization to ensure adequate safety.
- 15. SPOILAGE OF WINE Spoilage Casual Microorganisms Ester and aldehyde taints: increased volatile acidity Pichia, Hanseniaspora, Hansenula, Candida Formation of surface films Candida, Pichia Mousy, horsy taints Brettanomyces Refermentation in the bottle Saccharomyces, Zygosacchromyces, Bacilli Oxidized taint from acetaldehyde Sacchromycodes Ludwigii, Pichia Deacidification of wine Schizosccharomyces
- 17. SPOILAGE OF BEER
- 19. SPOILAGE OF SAUERKRAUT • Softness : Insufficient salt, high temperature during fermentation, uneven salt distribution or air pockets caused by improper packing. • Pink colour : growth of certain types of yeast on the surface of the kraut. These may grow if there is too much salt, an uneven distribution of salt or if the kraut is insufficiently covered during fermentation. • Roter kraut : found at the surface, where the cabbage has not been covered sufficiently to exclude air during Fermentation.
- 20. SPOILAGE OF PICKLE Blue or Green Garlic • Garlic contains sulfur compounds that might react with cooper to form cooper sulfate, a blue or blue – green compound. • Storing garlic bulbs in dry air for 32 days at or above 70 to 80 of before use will prevent formation of green or blue- green pigments. Black pickles • Formation of a ferrous sulfide complex • Due to growth of a blak-pigmented bacteria. Clouding of pickle • Cloudy liquid might be a sign of spoilage. Due to mold.
- 24. SAFETY OF FERMENTED FOODS
- 25. CONTROL OF MICROBIOLOGICAL SPOILAGE