MICROBIAL FOOD SPOILAGEMICROBIAL FOOD SPOILAGE

Dr. Ir. Eni Harmayani, M.Sc.Dr. Ir. Eni Harmayani, M.Sc.

Important Factors in Important Factors in Microbial Food SpoilageMicrobial Food Spoilage

Significance of Microbial Significance of Microbial TypesTypes► Raw and most processed foods normally contain Raw and most processed foods normally contain

many types of many types of bacteria (the first important component in spoilage due to a bacteria (the first important component in spoilage due to a

shorter generation time),shorter generation time), yeasts (favorable positions over molds to cause rapid yeasts (favorable positions over molds to cause rapid

spoilage of foods), spoilage of foods), molds, molds, capable of multiplying and causing spoilage.capable of multiplying and causing spoilage.

► However, in food where bacteria and yeasts do not However, in food where bacteria and yeasts do not grow favorably and the foods are stored for a grow favorably and the foods are stored for a relatively longer period of time (breads, hard cheese, relatively longer period of time (breads, hard cheese, fermented dry sausages, and acidic fruits and fermented dry sausages, and acidic fruits and vegetables) spoilage due to mold growth is more vegetables) spoilage due to mold growth is more prevalent.prevalent.

Significance of Microbial Significance of Microbial NumbersNumbers

►The spoilage detection level can range The spoilage detection level can range from 10from 1066 – 10 – 1088 cells/g, mL or square cells/g, mL or square centimeter.centimeter.

►Spoilage associated with HSpoilage associated with H22S, some S, some amines, and Hamines, and H22OO22 formation can be formation can be detected at a lower microbial load, detected at a lower microbial load, while formation of lactic acid may be while formation of lactic acid may be detected at a higher microbial load.detected at a higher microbial load.

Significance of Predominant Significance of Predominant MicroorganismsMicroorganisms► The microbial profile of a food is quite The microbial profile of a food is quite

different from that of a pure culture growing different from that of a pure culture growing in a laboratory medium.in a laboratory medium.

► An unspoiled, nonsterile food generally An unspoiled, nonsterile food generally contains many types of microorganisms contains many types of microorganisms consisting of bacteria, yeasts, and molds consisting of bacteria, yeasts, and molds (also viruses) from different genera and may (also viruses) from different genera and may be more than one species from the same be more than one species from the same genus.genus.

► When the same food is spoiled, it is found to When the same food is spoiled, it is found to contain predominantly one or two types, and contain predominantly one or two types, and they may not even be present initially in the they may not even be present initially in the highest numbers in the unspoiled product. highest numbers in the unspoiled product.

Some Important Food Spoilage Some Important Food Spoilage BacteriaBacteria► Psychrotrophic BacteriaPsychrotrophic Bacteria

Aerobic : Aerobic : Pseudomonas fluorescens, P. fragi, Pseudomonas fluorescens, P. fragi, other other Pseudomonas Pseudomonas species, species, Acinobacter, Moraxella, Acinobacter, Moraxella, and and Flavobacterium. Flavobacterium. (some molds and yeasts)(some molds and yeasts)

Facultative anaerobic : Facultative anaerobic : L. viidescens, L. sake, L. curvatus, L. viidescens, L. sake, L. curvatus, Leuconostoc mesenteroides Leuconostoc mesenteroides etc.etc.

Thermoduric psychrotrops : Thermoduric psychrotrops : ► Facultative anaerobs : spores of Facultative anaerobs : spores of Bacillus coagulans Bacillus coagulans and and

Bacillus megaterium, Bacillus megaterium, some strains of some strains of L. viridescens.L. viridescens.► Anerobes : spores of Anerobes : spores of Clostridium laramie, Clo. estertheticum, Clostridium laramie, Clo. estertheticum,

Clo. algidicarnis, Clo.putrefaciens, Clo. algidicarnis, Clo.putrefaciens, and unidentified and unidentified Clostridium Clostridium spp.spp.

► When a food is temperature abused above 5When a food is temperature abused above 500C, some true C, some true mesophiles (growth temperature range 15 – 45 mesophiles (growth temperature range 15 – 45 00C, optimum C, optimum 25 – 40 25 – 40 00C) can also grow.C) can also grow.

► However, at 10 – 15 However, at 10 – 15 00C storage temperature psychrotrophs C storage temperature psychrotrophs will generally grow much faster than these mesophiles.will generally grow much faster than these mesophiles.

► Thermophilic BacteriaThermophilic Bacteria The bacteria in this group grow between 40 – 90 The bacteria in this group grow between 40 – 90

00C, with optimum growth at 55 – 65 C, with optimum growth at 55 – 65 00C. C. Spores of some thermophilic Spores of some thermophilic Bacillus Bacillus and and

Clostridium Clostridium spp. can be present in these heat spp. can be present in these heat treated foods, which at warm temperatures treated foods, which at warm temperatures germinate and multiply to cause spoilage. germinate and multiply to cause spoilage.

Some thermoduric vegetative bacteria surviving Some thermoduric vegetative bacteria surviving low heat processing (such as pasteurization) or low heat processing (such as pasteurization) or thermophiles getting in food as post-heat thermophiles getting in food as post-heat contamination can also multiply in this warm contamination can also multiply in this warm foods, especially if the temperature is close to 50 foods, especially if the temperature is close to 50 00C.C.

►Aciduric BacteriaAciduric Bacteria Bacteria capable of growing relatively rapidly Bacteria capable of growing relatively rapidly

in food at pH 4.6 or below are generally in food at pH 4.6 or below are generally regarded as aciduric (or acidophilic).regarded as aciduric (or acidophilic).

Spoilage of acidic food products :Spoilage of acidic food products :►Fruit juices, pickles, salsa, salad dressings, Fruit juices, pickles, salsa, salad dressings,

mayonnaise, and fermented sausages. mayonnaise, and fermented sausages. Heterofermentative LAB and Heterofermentative LAB and

homofermentative LAB have been associated homofermentative LAB have been associated with such spoilage.with such spoilage.

Yeast and molds are aciduric and thus are Yeast and molds are aciduric and thus are associated with spoilage of such foods.associated with spoilage of such foods.

Food TypesFood Types

► Intrinsic factors that can cause food Intrinsic factors that can cause food spoilage : spoilage : Aw & pH : food with a lower Aw (0.90) or a Aw & pH : food with a lower Aw (0.90) or a

lower pH (5.3) is less susceptible to bacterial lower pH (5.3) is less susceptible to bacterial spoilage than one with Aw = 0.98 or pH = spoilage than one with Aw = 0.98 or pH = 6.4. Yeast and molds will probably grow 6.4. Yeast and molds will probably grow equally well under both conditions.equally well under both conditions.

O – R potential, nutrient content, O – R potential, nutrient content, antimicrobial substances, protective antimicrobial substances, protective structures.structures.

►Extrinsic factors : storage conditionsExtrinsic factors : storage conditions

Metabolism of Food NutrientsMetabolism of Food Nutrients

CarbohydratesCarbohydrates Food nutrientsFood nutrients LipidsLipids

Proteinaceous Proteinaceous and NPN and NPN compoundscompounds

COCO22, H, H22, H, H22OO22, , lactate, acetate, lactate, acetate, formate, butyrate, formate, butyrate, isobutyrate, isobutyrate, isovalerate, ethanol, isovalerate, ethanol, propanol, butanol, propanol, butanol, isobutanol, diacetyl, isobutanol, diacetyl, acetoin, butanediol, acetoin, butanediol, dextran, levans.dextran, levans.

COCO22, H, H22, NH, NH33, H, H22S, S, amines, keto acids, amines, keto acids, mercaptans, organic mercaptans, organic disufides, disufides, putrescine, putrescine, cadaverine, skatolecadaverine, skatole

Fatty acids, glycerol, Fatty acids, glycerol, hydroperoxides, hydroperoxides, carbonyl compounds carbonyl compounds (aldehydes, and (aldehydes, and ketones), ketones), nitrogenous bases.nitrogenous bases.

Preference for Utilization of Preference for Utilization of Food NutrientsFood Nutrients

► In general, microorganisms prefer to use In general, microorganisms prefer to use carbohydrate first, followed by NPN and carbohydrate first, followed by NPN and proteinaceous compounds, and then proteinaceous compounds, and then lipids. lipids. It again depends on whether or not a It again depends on whether or not a

particular species has the ability to use particular species has the ability to use specific carbohydrate.specific carbohydrate.

► In mixed microbial population, as In mixed microbial population, as normally present in food, availability and normally present in food, availability and amount of metabolizable carbohydrates amount of metabolizable carbohydrates greatly affect the spoilage pattern.greatly affect the spoilage pattern.

Microbial Growth in SuccesionMicrobial Growth in Succesion

►The intrinsic factors or environments The intrinsic factors or environments of a food dictate which, among the of a food dictate which, among the mixed microbial species normally mixed microbial species normally present, will multiply rapidly and present, will multiply rapidly and become predominant to cause become predominant to cause spoilage.spoilage.

► If sufficient time is given, the If sufficient time is given, the predominant microbial types and the predominant microbial types and the nature spoilage of a food can change.nature spoilage of a food can change.

Spoilage of Specific Spoilage of Specific Food GroupsFood Groups

Prevention of spoilagePrevention of spoilage

►Knowing types of microorganisms Knowing types of microorganisms associated with spoilage of specific associated with spoilage of specific foods is essential for developing foods is essential for developing preventive measurespreventive measures

► Intrinsic and extrinsic factors can be Intrinsic and extrinsic factors can be manipulated to prevent microbial manipulated to prevent microbial growthgrowth

Fresh and Ready to Eat Meat Fresh and Ready to Eat Meat ProductsProducts

► Raw MeatRaw Meat From animals and birds contain a large group of From animals and birds contain a large group of

spoilage bacteriaspoilage bacteria The predominant spoilage flora in a meat is The predominant spoilage flora in a meat is

determined by :determined by :► the nutrient and oxygen availability, the nutrient and oxygen availability, ► storage temperature, storage temperature, ► pH, pH, ► the storage time of the product the storage time of the product ► generation time of the spoilage microorganisms under a generation time of the spoilage microorganisms under a

given environment. given environment.

► Meat are more perishable than other food Meat are more perishable than other food commoditiescommodities Abundance all nutrients required for growth of Abundance all nutrients required for growth of

bacteria, yeasts and moldsbacteria, yeasts and molds All of these nutrients readily availableAll of these nutrients readily available Carcasses and cuts may be spoiled by bacteria or Carcasses and cuts may be spoiled by bacteria or

by moldsby molds► Whiskers (Whiskers (Mucor, RhizopusMucor, Rhizopus), black or green spots ), black or green spots

((Cladosporium, PenicilliumCladosporium, Penicillium)) Ground meats and steaks are almost exclusively Ground meats and steaks are almost exclusively

spoiled by bacteriaspoiled by bacteria► Storage temperature selects for psychrotropic spoilage Storage temperature selects for psychrotropic spoilage

organismsorganisms Pseudomonas, Moraxella, Acinetobacter, PsychrobacterPseudomonas, Moraxella, Acinetobacter, Psychrobacter Steaks tend to undergo surface spoilageSteaks tend to undergo surface spoilage

►Ready to Eat Meat ProductsReady to Eat Meat Products High heat processed uncured and cured High heat processed uncured and cured

meat products (heat treatment to make meat products (heat treatment to make them commercially sterile)them commercially sterile)

Low heat processed uncured and cured Low heat processed uncured and cured meat productsmeat products

Sources of microorganisms : Sources of microorganisms : ►Raw meatRaw meat►Spices and other ingredientsSpices and other ingredients►Natural casingsNatural casings

► Spoilage in ready to eat meat products :Spoilage in ready to eat meat products : Slimy spoilageSlimy spoilage

► Occurs on the outside of casingOccurs on the outside of casing Yeast, LAB, Yeast, LAB, B. thermosphactaB. thermosphacta

SouringSouring► Occurs underneath the casingOccurs underneath the casing

Due to growth of LABDue to growth of LAB

GreeningGreening► Due to HDue to H22OO22 production ( production (LactobacillusLactobacillus))

► Due to HDue to H22S production S production Reacts with myoglobin to form sulphmyoglobinReacts with myoglobin to form sulphmyoglobin Pseudomonas mephiticaPseudomonas mephitica

Eggs and Egg ProductsEggs and Egg Products

►RottingRotting Green rots (Green rots (Pseudomonas fluorescensPseudomonas fluorescens)) Colorless rots (Colorless rots (Pseudomonas, AcinetobacterPseudomonas, Acinetobacter)) Black rots (Black rots (ProteusProteus)) Pink rots (Pink rots (PseudomonasPseudomonas)) Red rots (Red rots (SerratiaSerratia)) Custard rots (Custard rots (Proteus vulgaris, P. intermediumProteus vulgaris, P. intermedium))

►Pinspots (molds, Penicillium, Pinspots (molds, Penicillium, Cladosporium, Mustiness, Cladosporium, Mustiness, P. graveolansP. graveolans, , ProteusProteus))

►Hen’s egg structure includes barriers Hen’s egg structure includes barriers against microbial entry and growth :against microbial entry and growth : ExternalExternal

►Outer waxy shell membraneOuter waxy shell membrane►ShellShell►Inner shell membraneInner shell membrane

Internal (white)Internal (white)►Lysozyme Lysozyme ►Avidin (chelates biotin)Avidin (chelates biotin)►High pH (~ 9.3)High pH (~ 9.3)►Conalbumen (chelates iron)Conalbumen (chelates iron)

Yolk is an excellent medium for bacterial Yolk is an excellent medium for bacterial growthgrowth

Milk and Milk ProductsMilk and Milk Products

► Raw MilkRaw Milk Microbiota of milk from healty cowsMicrobiota of milk from healty cows

► MicrococcusMicrococcus,, Staphylococcus, Staphylococcus, Lactic acid cocci Lactic acid cocci ((Lactococcus Lactococcus and and StreptococcusStreptococcus) )

Microbiota of milk from cows with mastitisMicrobiota of milk from cows with mastitis► Staphylococcus aureus, Streptococcus agalactiae, Staphylococcus aureus, Streptococcus agalactiae,

Coliforms, Coliforms, Pseudomonas, Pseudomonas, and other streptococciand other streptococci► Count > 10Count > 1033 in the bulk tank (if not separated) in the bulk tank (if not separated)

Spoilage of refrigerated milk consists usually of Spoilage of refrigerated milk consists usually of bitter, rancid, fruity flavors due to putrefaction bitter, rancid, fruity flavors due to putrefaction and caused by psychrotrophsand caused by psychrotrophs

Spoilage of milk at room consists usually of Spoilage of milk at room consists usually of souring due to fermentation and LABsouring due to fermentation and LAB

►Pasturized MilkPasturized Milk Usually associated with Gram-negative Usually associated with Gram-negative

psychrotrophspsychrotrophs►Bitter, rancid, fruity, or unclean flavorBitter, rancid, fruity, or unclean flavor

Gram-positive, psychrotrophic Gram-positive, psychrotrophic sporeformers (sporeformers (BacillusBacillus spp.), can grow spp.), can grow and cause spoilage (sweet curdling)and cause spoilage (sweet curdling)

Vegetables and FruitsVegetables and Fruits

► Widely varied products (raw, frozen, canned, Widely varied products (raw, frozen, canned, dehydrated, fermented)dehydrated, fermented)

► Sources of m.o in fresh vegetables and fruitsSources of m.o in fresh vegetables and fruits Soil (Soil (Bacillus, Clostridium, Bacillus, Clostridium, fungi)fungi) Wide distribution in nature (Wide distribution in nature (Lactobacillus, Lactobacillus,

Leuconostoc, StreptococcusLeuconostoc, Streptococcus)) Fertilizers (non-fermented manure)Fertilizers (non-fermented manure) Water (irigation, solvent, washing)Water (irigation, solvent, washing) Dust (air)Dust (air) Animals, insects, humansAnimals, insects, humans Harvesting equipment and utensilsHarvesting equipment and utensils Packing equipmentPacking equipment Ice, transporting vehicles, inadequate storages, Ice, transporting vehicles, inadequate storages,

cross contamination, handling previous to cross contamination, handling previous to consumptionconsumption

► Types of spoilage on Types of spoilage on vegetables and fruitsvegetables and fruits Bacterial soft rotBacterial soft rot

► Soft, mushy product, Soft, mushy product, sometimes with off-odorssometimes with off-odors

Souring by LABSouring by LAB Gray mold rot (Gray mold rot (Botrytis Botrytis

sp.), sp.), Rhizopus Rhizopus soft rot soft rot ((Rhizopus Rhizopus sp.) and many sp.) and many other rots caused by other rots caused by species of moldsspecies of molds

Bacteria are of less Bacteria are of less impotance in the spoilage impotance in the spoilage of fruits because of the of fruits because of the lower pHlower pH

Fish, Crustaceans, and MollusksFish, Crustaceans, and Mollusks

► FishFish Microbial spoilage is determined by the microbial Microbial spoilage is determined by the microbial

types, their level, fish environment, fish types, types, their level, fish environment, fish types, methods used for harvest, and subsequent methods used for harvest, and subsequent handling handling

► CrustaceansCrustaceans Microbial spoilage in shrimp is more prevalent than Microbial spoilage in shrimp is more prevalent than

that of crabs and lobsters because crabs and that of crabs and lobsters because crabs and lobsters remain alive until they are pocessedlobsters remain alive until they are pocessed

► MollusksMollusks As compared to fish and crustaceans, oyster, clam, As compared to fish and crustaceans, oyster, clam,

and scallop meats are lower in NPN compounds but and scallop meats are lower in NPN compounds but higher in carbohydrateshigher in carbohydrates

The mollusks are kept alive until processed; thus, The mollusks are kept alive until processed; thus, microbial food spoilage occurs only after processingmicrobial food spoilage occurs only after processing

Soft Drink, Fruit Juices and Soft Drink, Fruit Juices and Preserves, and Vegetable JuicesPreserves, and Vegetable Juices

► Among the microorganisms that can be Among the microorganisms that can be present in these products, only aciduric present in these products, only aciduric molds, yeasts, and bacteria (molds, yeasts, and bacteria (LactobacillusLactobacillus, , LeuconostocLeuconostoc, and , and AcetobacterAcetobacter) are able to ) are able to cause spoilage if appropriate preservation cause spoilage if appropriate preservation methods are not usedmethods are not used

► To prevent of these potential spoilage To prevent of these potential spoilage microorganisms, several additional microorganisms, several additional preservation methods are used, include :preservation methods are used, include : heat treatmentheat treatment, to kill vegetative , to kill vegetative

microorganisms in tomato juices,microorganisms in tomato juices, freezingfreezing,, refrigerationrefrigeration,, addition of specific chemical preservativesaddition of specific chemical preservatives..

(Harmayani & Sumedi, 2006)

Cereals and Their ProductsCereals and Their Products

► Cereal grainsCereal grains If the AIf the Aw w increase above 0.6, some species of fungi increase above 0.6, some species of fungi

((AspergillusAspergillus, , PenicilliumPenicillium, and , and RhizopusRhizopus) can grow and cause ) can grow and cause spoilage spoilage

Yeats are common on all cereals, although they represent Yeats are common on all cereals, although they represent only a minority of the microbial floraonly a minority of the microbial flora

► Refrigerated Dough (biscuits, roles, and pizza)Refrigerated Dough (biscuits, roles, and pizza) Susceptible to spoilage (gas formation) from the growth of Susceptible to spoilage (gas formation) from the growth of

psychrotrophic heterolactic species of psychrotrophic heterolactic species of Lactobacillus Lactobacillus and and LeuconostocLeuconostoc then the gas can blow the containers, especially then the gas can blow the containers, especially when the storage temperature increases to 10when the storage temperature increases to 1000C or aboveC or above

► BreadsBreads A specific type of bread spoilage, designated as ropiness and A specific type of bread spoilage, designated as ropiness and

characterized by soft, stringy, brown mass with fruity odor, characterized by soft, stringy, brown mass with fruity odor, caused by the growth of some mucoid variants of caused by the growth of some mucoid variants of Bacillus Bacillus subtilissubtilis

► PastasPastas Anaerobic packing and refrigeration storage can Anaerobic packing and refrigeration storage can

prevent mold growth and slow down the growth prevent mold growth and slow down the growth of yeasts, anaerobic and facultative anaerobic of yeasts, anaerobic and facultative anaerobic psychrotrophic bacteriapsychrotrophic bacteria

► PastriesPastries They can spoilage by microorganisms coming They can spoilage by microorganisms coming

with the ingredients that are added after baking with the ingredients that are added after baking such as icing, nuts, toppings, and creamsuch as icing, nuts, toppings, and cream

Due to low Aw, most products will allow only Due to low Aw, most products will allow only molds to growmolds to grow

Liquid Sweeteners and Liquid Sweeteners and ConfectioneriesConfectioneries

►Most of these products have an Aw of Most of these products have an Aw of 0.8 or below and are normally not 0.8 or below and are normally not susceptible to bacterial spoilage.susceptible to bacterial spoilage.

►Under aerobic conditions, some Under aerobic conditions, some xerophilic molds can produce visible xerophilic molds can produce visible spoilagespoilage

►Osmophilic yeasts Osmophilic yeasts Zygosaccharomyces Zygosaccharomyces rouxii, Saccharomyces cerevisiae, rouxii, Saccharomyces cerevisiae, Torulopsis holmii, Torulopsis holmii, and and Candida valida Candida valida can ferment these productscan ferment these products

Mayonnaise, Salad Dressing, and Mayonnaise, Salad Dressing, and CondimentsCondiments

►Zygosaccharomyces bailiiZygosaccharomyces bailii►Lactobacillus fructivoransLactobacillus fructivorans►Bacillus vulgatus Bacillus vulgatus ((Thousand IslandThousand Island

dressing)dressing)

Canned FoodsCanned Foods

► Thermophilic sporeformersThermophilic sporeformers Can cause some types of spoilage of low acid Can cause some types of spoilage of low acid

(high pH) foods (such as corn, beans, peas) when (high pH) foods (such as corn, beans, peas) when the cans are temperature abused at 43the cans are temperature abused at 4300C and C and above, even for short durationabove, even for short duration

► Spoilage due to insufficients heatingSpoilage due to insufficients heating Clostridium Clostridium and some and some Bacillus Bacillus spp.spp.

► Spoilage due to container leakageSpoilage due to container leakage Damage and leakly containers will allow different Damage and leakly containers will allow different

types of microorganisms to get inside from the types of microorganisms to get inside from the environment after heatingenvironment after heating

Fermented FoodsFermented Foods

► Fermented meat productsFermented meat products If the acid production of homofermentative LAB is If the acid production of homofermentative LAB is

slow, undesirable bacteria can grow (slow, undesirable bacteria can grow (Clostridium, Clostridium, Bacillus, Bacillus, and other mesophilic bacteria have been and other mesophilic bacteria have been reported to cause spoilage in such conditions.reported to cause spoilage in such conditions.

Products with pH < 5.0 but Aw 0.92 or above and Products with pH < 5.0 but Aw 0.92 or above and vacuum packaged can be spoiled by vacuum packaged can be spoiled by heterofermentative heterofermentative Leuconostoc Leuconostoc and and Lactobacillus Lactobacillus spp. with accumulation of gas and liquid inside the spp. with accumulation of gas and liquid inside the package and creamy white growth of bacterial package and creamy white growth of bacterial cellscells

If they are not vacuum packaged and have low Aw If they are not vacuum packaged and have low Aw (0.72-0.90), yeast and molds can grow on the (0.72-0.90), yeast and molds can grow on the surface, resulting in slime formation, discoloration, surface, resulting in slime formation, discoloration, and undesirable flavor of the products.and undesirable flavor of the products.

Yeast In Specific Types of FoodsYeast In Specific Types of Foods

► Yeast will actually grow to the extent that Yeast will actually grow to the extent that spoilage will result depends on intrinsic and spoilage will result depends on intrinsic and extrinsic factorsextrinsic factors

► Many yeast species are associated with plant Many yeast species are associated with plant and animal products and can also be found in and animal products and can also be found in food-processing environmentsfood-processing environments

► Yeast are most likely to cause spoilage in Yeast are most likely to cause spoilage in products such as fruits and soft drinks, which products such as fruits and soft drinks, which contain fermentable sugars, and in those contain fermentable sugars, and in those types of food, e.g., alcoholic beverages and types of food, e.g., alcoholic beverages and high-sugar and/or high-acidity products, high-sugar and/or high-acidity products, which restrict the growth of competing which restrict the growth of competing bacteria bacteria

Food fermented with mixed Food fermented with mixed cultures cultures of bacteria and fungiof bacteria and fungi

ProductProductss

MoldsMolds YeastsYeasts BacteriaBacteria SubstratSubstratee

UseUse

RagiRagi Amylomyces Amylomyces rouxiirouxii

Endomyces spp.Endomyces spp.

Pichia burtoniiPichia burtoniiPediococcus pentosaceusPediococcus pentosaceus

Steptococus faecalisSteptococus faecalisUncoked riceUncoked rice InoculuInoculu

m m

PeuyemPeuyem A.rouxiiA.rouxii P.BurtoniiP.Burtonii

Endomycopsis Endomycopsis fibulingerfibulinger

P.PentosaceusP.Pentosaceus

Enterococcus faecalisEnterococcus faecaliscassavacassava SnackSnack

MisoMiso Aspergillus oryzaeAspergillus oryzae

A.sojaeA.sojaeZygosaccharomyces Zygosaccharomyces rouxiirouxii

T.versatilisT.versatilis

P.HalophilusP.Halophilus

E.faecalisE.faecalisSoybeanSoybean

+ rice/barley+ rice/barleyFlavorinFlavoringg

Soy Soy saucesauce

A.OryzaeA.Oryzae

A.Sojae groupA.Sojae groupZy.rouxii, Zy.sojae, Zy.rouxii, Zy.sojae, Zy.major, Ha. Spp., Zy.major, Ha. Spp., Torulopsis spp., Torulopsis spp., C.etchellsii, C.etchellsii, C.versatilisC.versatilis

Lactobacillus delbrueckiiLactobacillus delbrueckii

P.halophilusP.halophilus

P.damnosusP.damnosus

SoybeanSoybean

+wheat+wheat

+salt+salt

FlavorinFlavoring g

SakeSake A.oryzaeA.oryzae Ha.anomalaHa.anomala

S.Cerevisiae (sake)S.Cerevisiae (sake)Lactobacillus Lactobacillus mesenteroides var.sakemesenteroides var.sake

Lactobacillus sakeLactobacillus sake

Rice Rice LiquorLiquor

TempeTempe Rhizopus Rhizopus oligosporusoligosporus

R.chinensisR.chinensis

R.OryzaeR.Oryzae

Mucor indicusMucor indicus

Trp.beigeliiTrp.beigelii

Cla.lusitaniaeCla.lusitaniae

C.maltosaC.maltosa

C.intermediaC.intermedia

Ya.lipolytica Ya.lipolytica

Klebsiella pneumoniaeKlebsiella pneumoniae

Enterobacter cloacaeEnterobacter cloacae

Lactobacillus spp.Lactobacillus spp.

Mostly Mostly soybeanssoybeans

Protein Protein food food snacksnack

(Deak dan Beuchat, 1996)

►Pustaka :Pustaka : Deak, T. dan Beuchat, L.R. 1996. Deak, T. dan Beuchat, L.R. 1996.

Handbook of Food Spoilage Yeast. CRC Handbook of Food Spoilage Yeast. CRC Press, New York.Press, New York.

Ray, B. 1996. Fundamental Food Ray, B. 1996. Fundamental Food Microbiology. CRC Press, New York.Microbiology. CRC Press, New York.

Nickerson, J.T. dan Sinskey, A.J. 1974. Nickerson, J.T. dan Sinskey, A.J. 1974. Microbiology of Food and Food Processing. Microbiology of Food and Food Processing. American Elsevier Publishing Co., Inc.American Elsevier Publishing Co., Inc.