1601657 A

Fermented milks: a historical food with modernapplications a review

AY Tamime1*

1Dairy Science and Technology Consultant, Ayr, Scotland, UK

Background: This paper was presented at the symposium which was organized by Instituto Danone Mexico in May 2001, and itprovides an overview of the current scientific knowledge on fermented milks concerning the historical developments,manufacturing stages, classification of such products, and nutritional aspects. Particular attention has been paid to thehuman health benefits associated with the consumption of these products, the use of probiotic starter cultures and theirindustrial applications, and the significance of using a trained sensory panel for the evaluation of probiotic fermented milks madewith different commercial blends of starter cultures. The paper also highlights the future research areas for the exploitation ofstarter microflora (Lactobacillus, Bifidobacterium and Enterococcus species) in fermented milk products.Conclusion: This review indicates that the complex metabolism of the starter cultures is well established; however, moreinformation is still needed on specific microbial metabolites such as polymerization of milk sugars for the production ofexopolysaccharides and the modification of the milk peptides and secretion of bacteriocins. More clinical studies are stillrequired to establish the functional health benefits of probiotic fermented milks to humans.Sponsorship: The visit to Mexico City was supported by Instituto Danone Mexico.European Journal of Clinical Nutrition (2002) 56, Suppl 4, S2 S15. doi:10.1038/sj.ejcn.1601657

Descriptors: review; fermented milks; starter cultures; probiotic microflora; health benefits

IntroductionFermented milks are widely produced in many countries.

This type of process is one of the oldest methods used to

extend the shelf-life of milk, and has been practised by

human beings for thousands of years. The exact origin(s) of

the manufacture of fermented milks is difficult to establish,

but it is safe to assume that it could date to more than

10 000 y ago as the way of life of humans changed from food

gathering to food producing (Pederson, 1979). This change

also included the domestication of certain mammals such as

the cow, sheep, goat, buffalo and camel; it is most likely that

the transition occurred at different dates in different

countries. However, archaeological evidence of certain

civilizations (Sumerians, Babylonians, Pharos and Indians)

suggests that they were well advanced in agriculture and in

the production of fermented milks.

It is likely that the origin of these products was the Middle

East and the Balkans, and the evolution of fermented milks

through the ages could be attributed to the culinary skills of

the inhabitants living in these regions. Todays fermented

milk products are manufactured in many countries, and the

stages of manufacture, which is still a complex process,

combine the art of such ancient craft and science (micro-

biology and enzymology, physics and engineering, and

chemistry and biochemistry) together.

This article summarizes the research findings on yoghurt

and probiotic fermented milk products made from cows

milk over the past century.

Diversity of fermented milksFermented milks are manufactured throughout the world,

and approximately 400 generic names are applied to tradi-

tional and industrialized products (Kurmann et al, 1992), but

in actual essence the list may only include few varieties. In

the 1980s, Kurmann (1984) attempted, in part, the classifica-

tion of fermented milks into a family tree (see Figure 1;

Bylund, 1995), which was based primarily on the optimum

*Correspondence: AY Tamime, Dairy Science and Technology Consultant,

24 Queens Terrace, Ayr KA7 1DK, Scotland, UK.

E-mail: [email protected]

European Journal of Clinical Nutrition (2002) 56, Suppl 4, S2S15 2002 Nature Publishing Group All rights reserved 09543007/02 $25.00

www.nature.com/ejcn

growth requirements of the starter cultures (ie mesophilic

and thermophilic microflora).

Nevertheless, taking into account the microorganisms

that dominate the product, including their principle

metabolites, Robinson and Tamime (1990) proposed a

scheme for the classification of fermented milks as follows:

lactic fermentations (a) mesophilic type, eg culturedbuttermilk, filmjolk, tatmjolk and langofil; (b) thermo-

philic type, eg yoghurt, Bulgarian butter-milk, zabadi,

dahi; and (c) therapeutic or probiotic type, eg acidophilus

milk, Yakult, ABT, Onka, Vifit); products within this

group constitute by far the largest number known

worldwide;

yeast lactic fermentations (kefir, koumiss, acidophilusyeast milk); and

mould lactic fermentations (villi).Tamime and Marshall (1997) have detailed the manufac-

turing stages of these types of fermentations. However, the

so-called fermented milk drinks and=or beverages including

the carbonated products should be classified separately

rather than being known as fermented milks; such an

approach will minimize confusion among consumers. Never-

theless, some closely related products are manufactured from

fermented milks by de-wheying, and some examples are

labneh, skyr and ymer. The different methods available to

manufacture concentrated fermented milks are as follows:

(a) cloth bag or Berge system; (b) mechanical or nozzle

separators; (c) ultrafiltration (UF); and (d) product formula-

tion (Tamime & Robinson, 1999).

Patterns of consumptionUntil the 1950s, production and=or consumption of yoghurt

(ie natural type) was confined to communities in the Middle

East, the Balkans, India, Eastern Europe, to ethnic groups

living in different parts of the world, and to those who

perceived that the product was beneficial to health. How-

ever, consumers attitudes towards yoghurt have changed,

possibly for the following reasons: (a) as refrigeration became

widespread worldwide, the product became widely distribu-

ted and readily available on the market; (b) the introduction

of a new generation of yoghurts (eg addition of fruits and

sugar) gave the product an entirely fresh image and it

became an inexpensive snack or dessert; and (c) the advent

of incorporation of probiotic bacteria into the product have

enhanced the health benefits of fermented milks.

Consumption figures reflect the expanding markets in

some selected countries between 1970 and 1999 (Table 1).

Until the early 1990s, fermented milks were classified as

buttermilk, yoghurt and others according to the statistical

data published by the International Dairy Federation, and

such information provided consumption preferences of con-

sumers in different countries; the current approach of

Figure 1 The family tree of fermented milk types. Adapted from Kurmann (1984).

Fermented milks a reviewAY Tamime

S3

European Journal of Clinical Nutrition

per capita consumption figures covers milk drinks and fer-

mented milks including yoghurt. It could be argued, how-

ever, that this classification of these products may not

provide a clear picture or patterns of consumption. Further-

more, in some countries, the consumption of buttermilk is

not properly defined because:

traditional=natural buttermilk is the by-product of buttermaking from ripened or cultured butter;

cultured buttermilk is the fermentate of skimmed milkfollowed by the addition of butter flakes; and

sweet buttermilk is not fermented; hence the data forbuttermilk in such statistical tables have to be assessed in

a cautious manner.

It is safe to conclude that fermented milk products that

fall within the category of lactic fermentations (mesophilic

type) are widely consumed in northern European countries,

whilst the yeast lactic fermented milks are popular in the

Russian Federation, eastern European countries and Mongo-

lia. Conversely, natural yoghurt is popular in countries

between the Balkans and the Indian sub-continent, while

the fruit flavoured and=or flavoured products are normally

consumed in the rest of the world.

Little data is available on the world production figures of

probiotic-fermented milks but during the last decade produc-

tion has increased dramatically in some selected countries.

For example, the French market of fermented milk

containing Bifidobacterium spp. and Lactobacillus acidophilus

increased from 1500 to >91 000 tonnes between 1986 and

1990 (Renard, 1998).

Definition and terminology of fermented milksincluding yoghurtThe existing legal standards or the provisional regulations of

yoghurt in many countries classify the product on the basis

of chemical composition or fat content (full, semi-

skimmed=medium or skimmed=low); the reviews by Robin-

son and Tamime (1976), Pappas (1988), Anonymous (1989,

1996), FAO=WHO (1990), and Tamime and Robinson (1999)

are recommended for further reading.

The International Dairy Federation (IDF, 1992a,b) pub-

lished general standards of identity of fermented milks that

could be briefly defined as follows: Fermented milks are

prepared from milk and=or milk products (eg any one or

combinations of whole, partially or fully skimmed, concen-

trated or powdered milk, buttermilk powder, concentrated or

powdered whey, milk protein (such as whey proteins, whey

protein concentrates, soluble milk proteins, edible casein

and caseinates), cream, butter or milkfat all of which

have been manufactured from raw materials that have

been at least pasteurized) by the action of specific

microorganisms, which results in a reduction of the pH

and coagulation. It is of interest that in some countries the

fortification of milk components with dried dairy ingredi-

ents during the manufacture, of yoghurt for example, is

against the existing legal standards.

Other IDF specifications include the following aspects: (a)

the starter cultures shall be viable, active and abundant

(107 cfu=g) in the finished products at all times of sale forconsumption; (b) these products may or may not be homo-

genized, must at least be pasteurized, contain certain per-

mitted additives (optional), and have a shelf-life up to 30

days at 4 7C; (c) post-fermentation heat treatment shallnot be allowed; and (d) de-wheying after fermentation is

only permitted during the manufacture of concentrated

fermented milk products such as labneh, ymer, skyr and

stragisto. Furthermore, the identity of the starter cultures is

also detailed and, in the case of yoghurt, Streptococcus thermo-

philus (formerly known as S. salivarius subsp. thermophilus)

and Lactobacillus delbrueckii subsp. bulgaricus are normally

used because of the associative growth that exists between

these two microorganisms, whilst in some countries, Lacto-

bacillus helveticus and Lactobacillus delbrueckii subsp. lactis (ie

non-traditional organisms) are sometimes mixed with the

starter culture. However, the name(s) of the so-called bio,

therapeutic and=or probiotic fermented milks is not well

established and should be addressed because consumers

and=or some manufacturers in different countries consider

all these products to be yoghurt (for more details refer to

subsequent section).

The milk fermentates by mesophilic microorganism

include the products that are grouped under lactic and

yeast lactic fermentations. The starter microorganisms of

Table 1 Per capita annual consumption (kg=head) of milk drinksand fermented products including yoghurt

Country 1975 1980 1990 1999

Australia 1.0 1.8 3.5 5.8

Austria 7.9 9.8 10.4 15.1

Belgium 11.8 7.7 8.4 20.3

Canada 5.1 2.3 3.7 4.2

Chile NRa

1.4 3.9 6.7

Czech=Slovakia 3.9 7.3 NR 20.0

Denmark 36.1 26.7 21.6 29.8

Federal Germany 16.5 10.1 14.2b 25.5b

Finland 32.6 41.0 38.3 NR

France 9.6 9.3 16.4 27.4

Iceland 1.7 5.7 24.6 NR

Israel 14.1 14.3 NR 29.3

Italy NR 1.3 4.0 NR

Japan 2.5 2.4 7.8 NR

Netherlands 24.7 27.3 32.5 NR

Norway 9.8 10.1 14.9 19.9

Poland 3.2 2.0 NR 7.9

Spain 3.4 6.0 8.0 15.4

Sweden 24.1 23.5 29.1 30.2

Switzerland 16.4 14.8 19.0 NR

UK 1.7 2.8 4.4 NR

USA 9.9 3.1 3.5c NR

aNRnot reported.

bData includes German Democratic Republic.cData for 1993.

Data compiled from Tamime and Robinson (1999) and IDF (2000).


S4


the former group belong to the genera of Lactococcus(Lac. lactis

subsp. lactis, Lac. lactis subsp. lactis biovar diacetylactis and Lac.

lactis subsp. cremoris) and Leuconostoc (Leu. mesenteroides

subsp. cremoris and Leu. mesenteroides subsp. dextranicum),

and they are normally used as mixed cultures. However, the

microflora of the latter products is complex and not always

constant; numerous species of lactic acid bacteria, yeasts and

moulds have been found, for example, in the kefir grains.

Tamime and Marshall (1997) have detailed the organisms that

have been identified by many researchers in many countries.

Traditionally, many products are made from natural

yoghurt in the Balkans and the Middle Eastern countries

and these can be briefly described as follows: (a) dilution of

the fermentate with water for the production of drinking

yoghurt; (b) concentration of the yoghurt by de-wheying for

the manufacture of strained yoghurt and yoghurt cheese; the

latter product is formed into small balls and preserved in

olive oil; (c) cultured butter and=or ghee can be made by

churning full-fat yoghurt, and the aqueous phase is either

utilized as drinking yoghurt or mixed with parboiled cracked

wheat which is later sun-dried and milled into powder (such

product is known as Kishk); and (d) surplus of yoghurt is

preserved by drying or gently heating yoghurt for few hours

over low and smokey fires (the end product is known as

smoked yoghurt). Nevertheless, at present the classical

approach to categorize yoghurt products is based on its

physical characteristics as shown in Table 2 and, in particu-

lar, yoghurt is further sub-divided into different groupings

based on the following aspects:

legal and=or proposed standards classify the product, forexample, on the fat content (full, medium or low);

physical nature of the product (ie set or stirred; drinkingyoghurt is normally considered as stirred-type of low

viscosity);

flavours of yoghurt are divided into plain=natural,fruit or flavoured; the latter two products are normally

sweetened;

probiotic, bio and=or therapeutic yoghurts containnon-traditional organisms beside Lb. delbrueckii subsp.

bulgaricus and S. thermophilus (see Table 5);

miscellaneous yoghurts include pre-fermentation proces-sing (lactose hydrolysis or replacement of the animal fat

with vegetable oil) or post-fermentation processing (vita-

min fortification or heat treatment).

Technology of manufactureCurrently, the technological aspects of fermented milks are

well established and extensively reviewed (Rasic & Kur-

mann, 1978; IDF, 1984, 1986, 1988, 1992c; Chandan,

1989; Tamime & Marshall, 1997; Tamime & Robinson,

1999). The principal manufacturing stages and=or processes

for all fermented milk products (set- or stirred-type) have

many features in common, which can be briefly described

as follows:

Preparation of the milk base

The fat and the non-fat solid (SNF) contents of the milk are

standardized and fortified to ensure compliance with exist-

ing legal standards. The fat level may range between

Heat treatment

Different temperatures are used for the heat treatment of the

milk base during the manufacture of fermented milk, and

can vary depending on the time and temperature combina-

tions. Some examples are: (a) 85C for 30 min; (b) 90 95Cfor 5 min; and (c) 105C for 10 s. Thermal treatment of themilk base induces numerous physical and chemical changes

that are complex and multi-functional; the topic has been

extensively studied (see the reviews by IDF, 1995; Tamime &

Marshall, 1997; Tamime & Robinson 1999), and in the

context of fermented milks the effects of heat treatment are:

destruction and=or elimination of pathogens and othermicroorganisms present in the milk base and, hence, the

processed milk provides a good growth medium for the

starter cultures;

changes in the physical chemical properties of themilk constituents, mainly the denaturation of the b-lactoglobulin, which forms a complex with k-casein;such interaction minimizes syneresis and improves the

firmness of the gel; the protein=fat interaction in milk

should not be overlooked;

production of components that are stimulatory to thestarter cultures.

Starter culture

The heated milk base is cooled to the desired incubation

temperature of the product; some examples are: (a) yoghurt

at 40 45C for up to 3 h, at 30C for 18 h or 5 h whenusing direct-to-vat inoculation (DVI) starter culture; (b) pro-

biotic products at 37C for a few hours or up to 5 7 daysdepending on the organism(s) used; (c) buttermilk at 20

30C for up to 10 20 h; and (d) kefir at 22C for 16 24 hdepending on the type of kefir grains used (Tamime &

Marshall, 1977; Wszolek et al, 2001).

Gel formation in milk is mediated by acid coagulation

due to the activity of the starter cultures and their enzymes

to hydrolyse the lactose and to a lesser degree the proteins.

The mechanisms involved of casein dissociation and aggre-

gation during acid-induced gelation of milk are pH-, ion

concentration- and temperature-dependant, and these

aspects of gelation are similar for set- or stirred-type fer-

mented milks; in the former type, the milk is incubated in

the retail container, whilst for the stirred product the milk

is incubated in large fermentation tanks.

Cooling and miscellaneous handling

Cooling is only method used to control the metabolic

activity of the starter cultures and their enzymes in order

to retain an abundant count of these organisms in fermen-

ted milks. The primary objective is to cool the product to

5C, and the process of cooling commences at 4.6 pH,which is carried out using a one- or two-phase cooling. The

latter method is widely applied during the manufacture of

fruit-flavoured fermented milk products; the first stage of

cooling, for example for yoghurt, reduces the temperature

from 45 to 20 25C prior to the addition of fruit and packa-ging, and the second phase of cooling takes place in the cold

store (chill tunnel is optional), where the product is cooled to

countries. Nevertheless, who could have imagined in the

1950s that these products would be used successfully for the

treatment of certain human diseases in the 1980s or 1990s?

(See also Shortt, 1999.)

Probiotic microorganismsThe current definition of probiotics, as agreed by European

scientists, is a live microbial feed supplement that is

beneficial to health (Salminen et al, 1998a). However, the

microflora of the human intestinal tract in both infants and

adults is highly complex and many bacterial species have been

identified; the topic has been extensively researched, and the

following selected reviews provide relevant information with

specific emphasis on probiotic microorganisms and their

health applications to humans (Robinson, 1991; Fuller,

1992, 1997; Sanders, 1994; Salminen et al, 1996a, 1998b, c;

Marshall & Tamime, 1997a; Holzapfel et al, 1998; Salminen &

von Wright, 1998; Dunne et al, 1999; Hirayama & Rafter, 1999;

Lee et al, 1999; Tannock, 1999; Fuller & Perdigon, 2000;

Salminen, 2001). Periodically, Danone Vitapole Recherche

publishes monographs (Capron et al, 2000; Malagelada et al,

1999; Denariaz et al, 1999; Gibson et al, 2000; Hartley et al,

2001) and World Newsletter (23 issues have been published)

updating the health aspects associated with fermented milks.

As mentioned earlier, lactic acid bacteria, yeast, moulds or

combinations of these are widely used in the production of

fermented milks and cheeses. The characteristics of these

microorganisms have been recently reviewed by Tamime

(2002), and only the relevance of probiotic microflora in

fermented milks will be discussed. It is evident that these

bacterial species have to withstand the acidic and bile salts

conditions in the gastro-intestinal tract of humans when

compared with traditional dairy starter cultures, and reach

and=or colonize the large intestine. Researchers in different

countries have identified many probiotic microorganisms,

and Table 3 illustrates some examples.

The recent taxonomy and physiology of probiotic lacto-

bacilli species have been reported by Klein et al (1998), and

these species belonged to: (a) Lb. acidophilus group; (b) Lb. casei

group; and (c) Lb. reuteri=Lb. fermentum group; most Lb.

acidophilus strains used in the manufacture of probiotic

fermented milks have been identified as Lb. johnsonii or

Lb. gasseri; both species are members of the Lb. acidophilus

group. Hence, the issue of health-promoting properties of

such products is questionable, and it cannot be assumed that

all strains of Lb. acidophilus have or possess the desirable

properties of probiotic microorganisms (Salminen et al,

1996b; Hamilton-Miller & Gibson, 1999; Ouwehand et al,

1999); furthermore, not all the commercial probiotic fer-

mented milk products disclose the strain or species used or

the actual numbers (Hamilton-Miller, 1999; Sanders & Huis

int Veld, 1999). In some instances, researchers have referred

to Lb. rhamnosus GG as Lb. acidophilus, Lb. casei subsp. casei

or Lb. paracasei subsp. paracasei.

Until the mid 1980s, the genus Bifidobacterium was classi-

fied as Lactobacillus spp. and currently 30 different species of

bifidobacteria have been identified. The six organisms that

have been used in dairy products are shown in Table 3 but,

according to Klein et al (1998), most of the strains used in

Table 3 Examples of probiotic micro-organisms thatare used during the manufacture of fermented milks

Genera Microbial species

Lactobacillus Lb. acidophilus

Lb. acidophilus strains LC1,

La5, La1, La7, Gilliland

Lb. casei strains Shirota, GGa

or LGG,a Imunitass, NCC208

Lb. rhamnosus strain GG

Lb. johnsonii

Lb. helveticus

Lb. delbrueckii subsp. bulgaricus

Lb. gasseri

Lb. plantarum

Lb. paracasei subsp. paracasei

and subsp. tolerans

Lb. reuteri

Pediococcus P. acidilactici

Bifidobacterium B. bifidum, breve, longum,

adolescentis, infantis,

lactis, animalis

Lactococcus Lc. lactis subsp. lactis

Enterococcus E. faecium, faecalis

Saccharomyces S. boulardiib

aThis strain could be confused with Lb. rhamnosus GG due

to latest nomenclature classification.bMost likely application is during the manufacture of kefir.

Data compiled from Tamime et al (1995), Tamime and

Marshall (1997), Shortt (1997), Lee et al (1999) and

Sanders and Huis int Veld (1999).

Table 4 A summary of some health-promoting activities inhumans associated with probiotic fermented milks

Action=effect Alleged health benefit

In digestive tract Active against Helicobacter pylori

Enhanced lactose digestion

Stimulation of the intestinal immunity

Stabilization of Crohns disease

Stimulation of intestinal peristalsis

On intestinal

microflora

Improves balance between

microbial populations

(eg increase in faecal bifidobacteria)

Decrease in faecal enzyme activity

Colonisation of the intestinal tract

Reduced carrier time for Salmonella spp.

On diarrhoea Prevention=treatment of

acute and of Rotavirus diarrhoeas

Prevention of antibiotic-induced diarrhoea

Treatment of relapsing Clostridium difficile

diarrhoea

Other effects Improved immunity to disease

Suppression of some cancers

Reduction in serum cholesterol

Reduction in hypertension

Adopted from Tamime and Robinson (1999).


S7


probiotic fermented milks are B. animalis, although they

are declared on some labels as B. longum. B. animalis was

renamed B. lactis in the late 1990s (Meile et al, 1997), and

now it is re-classified as B. animalis (Cai et al, 2000). In my

view, the term bifidus should not be used because it is old

terminology (Lactobacillus bifidus), and can cause some con-

fusion to the reader.

The 16S rRNA sequencing within the genus Entrococcus

has revealed the presence of three species groups: E. faecium

and E. durans are found in the first group, whilst E. faecalis

forms an individual line of descent. However, the pathogeni-

city of these organisms should not be overlooked when they

are used in probiotic fermented milk products.

Limited data are available on the use of the probiotic yeast

(Saccharomyces boullardii) in fermented milks (Lourens-

Hattingh & Viljoen, 2001a), and the most likely application

is Kefir and Koumiss making. Other non-lactic acid bacteria

that have been used in probiotic products around the world

include Bacillus cereus, Escherichia coli and Clostridum

butyricum (Shortt, 1999).

Therapeutic properties of bio-fermented milksIt is well established that the probiotic microorganisms

shown in Table 3 have therapeutic properties, and when

they are added with traditional starter cultures during the

manufacture of fermented milks (see later), such products

have certain health-promoting activities in humans; Table 4

attempts to highlight the possible advantages. However, up-

to-date reports on some of the clinical=nutritional studies on

humans using probiotic fermented milks and their successful

applications in the treatment of certain human diseases,

include the following: (a) adherence of probiotic microor-

ganisms to human intestinal cells; (b) decreasing faecal

mutagenecity; (c) improvement of constipation; (d) produc-

tion of bacteriocins; (e) effects on superficial bladder cancer;

and (f) effect on the human salivary microflora (Mattila-

Sandholm & Salminen, 1998; Salminen et al, 1998b; Mattila-

Sandholm et al, 1999a,b; Ouwehand et al, 1999; Petti et al,

2001). Some selected studies on nutritional aspects relating

to humans have been reported by Oberhelman et al (1999),

Alander et al (1999), Lee et al (1999), Kar (1999), Ashar and

Table 5 Some examples of probiotic fermented milk products available in different countries

Product Country Microorganismsa

I. Fermented milks

ABT, Biogarde1, Philus Germany Lb. acidophilus B. lactisb or bifidum S. thermophilusUK

Denmark

Sweden

ACT4 Austria Similar to ABT Lb. caseiVifit, Gefilus Germany Yogurtc B. bifidum Lb. acidophilus Lb. rhamnosus GG

UK

Netherlands

Belgium

Finland

SymBalance Switzerland Lb. casei Lb. reuterix Lb. acidophilus BifidobacteriadActimel France Yogurt Lb. casei strain ImunitasseBiola Norway B. lactis Lb. rhamnosus Lb. acidophilusGaio Denmark S. thermophilus E. faecium

UK

Germany

Finland

BRA Sweden B. infantis Lb. reuteri Lb. acidophilusII. Fermented milk beverages

Onaka He GG Japan Yogurt Lb. rhamnosus GGYakult Japan Lb. casei strain Shirota

Brazil

Some Asian countries

Caldus Japan B. longum Lb. acidophilusVitagen Malaysia Lb. acidophilus

Singapore

Aktifit Switzerland Similar to ABT Lb. rhamnosus GGfLC1 or LC1 GO Many European countries Lb. acidophilusg or Lb. helveticus

aLb. Lactobacillus; S. Streptococcus; B.Bifidobacterium; E. Enterococcus.

bCurrently it is reclassified as B. animalis (Cai et al, 2000).

cYogurt Lb. delbrueckii subsp. bulgaricus S. thermophilus.dYogurt starter cultures have been found in the product rather than bifidobacteria (Sanders & Huis int Veld, 1999).eLb. casei Lb. delbrueckii subsp. bulgaricus were the only organisms identified in the product (Sanders & Huis int Veld, 1999).fLb. rhamnosus was the only organism present in the product (Sanders & Huis int Veld, 1999)gLb. johnsonii S. thermophilus were found in the product (Sanders & Huis int Veld, 1999).

Data compiled from Tamime et al (1995), Tamime (1998), Sanders and Huis int Veld (1999) and Lee et al (1999).


S8


Prajpati (1999), Arunachalam (1999), Barone et al (2000),

Heyman (2000), Arunachalam et al (2000), Ahn et al (2000),

Chiang et al (2000), Meydani and Ha (2000), Armuzi et al

(2001), Collins (2001), Volpe et al (2001), Kawase et al (2001),

Perdigon et al (2001) and Reid et al (2001).

Another aspect, which has links with gut health, involves

prebiotics; they are defined as non-digestible food ingredi-

ents that beneficially affect the host by selectively stimulat-

ing the growth and=or activity of one or limited number of

bacteria in the colon, that have the potential to improve the

host health (Gibson & Roberfroid, 1995). Most potential

prebiotic food ingredients are carbohydrate-based compo-

nents such as oligosaccharides (Hartemink, 1999; Gibson &

Angus, 2000). However, a mixture of probiotic microorgan-

isms and prebiotic food ingredient is known as synbiotic.

Commercial probiotic fermented milk productsSome of the critical aspects that can affect the quality of

fermented milks are: (a) good make which is attributed to

fast acid development using traditional starter cultures; acid

development of probiotic starter cultures is poor in compar-

ison with Lb. delbrueckii subsp. bulgaricus and S. thermophilus;

(b) stable product after manufacture where few undesirable

microorganisms can withstand the rapid acid development

or initiate growth at pH 4.6; and (c) the lactic and sour

flavour is the characteristic flavour acidity of majority of

traditional types of mesophilic and thermophilic fermented

milks, and the action of acid on the milk proteins (mainly

the casein) is important in texture formation of the product.

However, the heterofermentation by the bifidobacteria

results in lactic and acetic acid production; the latter acid

has a harshness which is undesirable for milk products

(Marshall & Tamime, 1997b).

As a consequence, the majority of commercially avail-

able probiotic fermented milks in different markets of the

world (ca 80 100) are made with a mixture of non-tra-

ditional and traditional starter cultures, and detailed exam-

ples have been reported by Hoier (1992), Tamime et al

(1995), Tamime & Marshall (1997), Holzapfel et al (1997)

Table 6 Some selected bacteriocins produced by dairy starter cultures and probiotic microflora

Genera=microorganisms Bacteriocins Molecular mass range (kDa)

I. Lactococcus

Lac. lactis subsp. lactis Lactostrepcin, Nisin, Lacticin, Bacteriocin,

Dricin, Lactococcin

1.3 >10

Lac. lactis subsp. lactis biovar diacetylactis Bacteriocin, Lactococcin, Lactocin, Diacetin 3.4 5.8

Lac. lactis subsp. cremoris Lactococcin, Bacteriocin, Diplococcin 3.4 8.5

II. Leuconostoc

Leu. mesenteroides subsp. mesenteroides Mesenterocin, Leucocin 2.5 100

IV. Lactobacillus

Lb. acidophilus Lactacin, Acidophilin, Acidophilicin,

Acidocin, Acidolin, Bacteriocin

0.2 50

Lb. johnsonii Lactacin 2.5 > 300

Lb. gasseri Bacteriocin, Gassericin 4.5 5.6

Lb. reuteri Reutericyclin, Reutericin 0.4 > 200

Lb. casei Caseicin 41Lb. plantarum Plantaricin 1 5.9

Lb. rhamnosus Bacteriocin

and Tamime (1998) (see Table 5); hence, probiotic micro-

organisms are used as therapeutic adjuncts in fermented

milk products (see also the review by Lourens-Hattingh &

Viljoen, 2001b).

Exopolysaccharides (EPS) productionMicrobial EPS material is synthesized by certain strains of

lactic acid bacteria, and it can enhance the rheological

properties (ie minimize syneresis, improve the texture and

modify the structure) and sensory perception (ie firmness

and creaminess) of fermented milks and other dairy pro-

ducts. The topic has been extensively reviewed (IDF, 1998;

Cerning & Marshall, 1999), and illustrations of the micro-

structure of both mesophilic and thermophilic fermented

milks have been reported by Tamime and Marshall (1997)

and Tamime and Robinson (1999).

Quantitative and qualitative properties of EPS material are

influenced by the following aspects: (a) microbial strain; (b)

composition of the growth medium and=or growth factors;

and (c) processing conditions that include the growth tem-

perature and time of fermentation. In 2001, the scientific

papers presented at the first Symposium on EPS from Lactic

Acid Bacteria provided an up-to-date review of this field,

including their applications in the dairy industry and the

structures of EPS (Monsan et al, 2001; de Vuyst et al, 2001;

Boels et al, 2001; Jolly & Stingele, 2001; Degeest et al, 2001;

Duboc & Mollet, 2001; Marshall et al, 2001). However, some

of these EPS materials contain gluco- and=or fructo-oligosac-

charides and may generate short-chain fatty acids upon

hydrolysis in the intestinal tract by the colonic microflora,

and may have potential health (eg an anti-tumor effect,

cholesterol-lowering effects or immune-modulators effects)

and nutritional benefits as a prebiotic to the intestinal

microflora.

Bacteriocin productionBacteriocins are antibacterial substances produced by

certain groups of microorganisms including probiotic and

lactic acid bacteria; they are also known as colicin-like

inhibitory substances. Incidentally, bacteriocins are usually

segregated from antibiotic compounds, and such naturally

produced metabolites inhibit the growth of undesirable

microorganisms in food and dairy products. In the case

of lactic acid bacteria, the bacteriocins produced could be

used to replace added chemical preservatives and, hence,

the shelf-life of the product could be extended by natural

means; however, these inhibitors can also affect certain

strains of starter cultures.

At present more than 70 different types of bacteriocins

have been identified as produced by lactic acid bacteria.

Table 6 summarizes some selected characteristics (for further

information refer to de Vuyst & Vandamme, 1994; Holzapfel

et al, 1995; Desmazeaud, 1994; Nes et al, 1996; Richard, 1996;

Marshall & Tamime, 1997a).

Partial characterization of the quality ofprobiotic fermented milksMany diversified probiotic dairy products are currently avail-

able to consumers in many markets, and some examples are:

pasteurized liquid milk, cheeses, ice-cream, milk powder feed

for infants and fermented milks (Tamime & Marshall, 1997).

However, fermented milk products are the most popular

vehicle used in the industry for the implantation of the

probiotic microflora in humans. In the mid 1990s, a colla-

borative research programme was established between the

Scottish Agricultural College (SAC) and the Hannah Research

Institute (HRI) to evaluate the quality (chemical composi-

tion, microbiological analysis, rheological properties and

sensory perception) of different types of newly developed

Table 7 The microorganisms used in commercial mixed starter cultures

Bifidobacterium spp. Lactobacillus spp.

Streptococcus

Code Supplier Typea bifidum lactisb longum infantis acidophilus bulgaricusc thermophilus

AB Chr. Hansen FD P P PAC=BL Rhodia FD P P PDVB-100 SBId FD P P PMSK 2 Visby DF P P PABT 1

eChr. Hansen FD P P P P

ABT 3 Chr. Hansen FD P P P PMSKB 2

eVisby FD P P P P

MY 087f Rhodia FD P P

aFD freeze dried, DFdeep frozen.

bCurrently it is reclassified as B. animalis (see text).

cLb. delbrueckii subsp. bulgaricus.dSBI Systems Bio-Industries Ltd.eThe starter cultures produces exopolysaccharide (EPS) materialfThis is a yoghurt starter culture, which is used as a control.

The symbol (P) denotes the presence of the microorganism in the starter culture.


S10


fermented milk products (eg vegetable oil yoghurt, kishk,

yoghurt made with fat substitutes, kefir and probiotic fer-

mented milks). In this paper, some aspects of the quality of

probiotics fermented milks will be reported, and for further

details refer to La Torre (1997), Hartley et al (2001) and La

Torre et al (2002).

In the first instance, single strains of Bifidobacterium spp.

(B. adolescentis NCFB 2230, B. bifidum NCFB 2715, B. breve

NCFB 2258, B. infantis NCFB 2205 and B. longum NCFB 2259,

were obtained from National Collection of Food Bacteria;

B. longum BB 46 and B. bifidum BB11 B. longum BBL and BL

and B. infantis 410 B. longum 2 and 913 were obtained from

Chr. Hansen, Rhodia and Visby, respectively) were used to

manufacture fermented milks. The quality of the products

made with the NCFB strains did not satisfy the minimum

requirements, the pH values were borderline (eg between 4.8

and 5.4), excessive whey separation was evident, the coagu-

lum was extremely week and, in some cases, the odour and

taste were unpleasant. However, slight improvement in the

quality of the product was evident, especially when the milk

bases were fortified with Raftaline1 or Jerusalem artichoke,

but the overall pHs ranged between 4.79 and 5.91 after 24 h

of incubation (with the exception of strains of B. longum BBL

and 2; pH 4.6). As the results were not satisfactory, it wasdecided that commercial mixed blends of starter cultures

containing lactic acid bacteria and different Bifidobacterium

species would be used (see Table 7).

The quality of the fermented milks was superior to those

made with single strains of bifidobacteria, and the results

could be summarized as follows:

Acidification of the milk base (total solids, protein and fatwere 14.5, 5.5 and 1.5 g=100 g, respectively) ranged

between 6 and 10 h or 13 and 22 h for pH 4.4. Organic acid profiling indicated that the starter cultures

produced appreciable quantities of lactic acid, and only

two cultures (AB and AC=BL) produced the high levels of

acetic acid (3229 and 2794 mg=g, respectively; figures areaverages of three trials and of fresh and stored products).

The viable cell counts in fresh and stored products forbifidobacteria varied (eg two cultures (AB and AC=BL)

showed an increase, three cultures (DVB-100, ABT 3 and

MSKB 2) remained constant, and two cultures (ABT 1 and

MSK 2) exhibited a slight decline); Lb. acidophilus

increased during production but, in some products (DVB-

100, MSK 2, ABT 1 and 3 and MSKB 2), the counts were

Figure 2 Sensory space maps for probiotic fermented milks, factorscores on first two dimensions are shown. For starter cultures symbolsrefer to Table 7. After La Torre (1997).

Figure 3 Interpretation of sensory results for fermented milk products. After La Torre (1997).


S11


decreased after storage; S. thermophilus counts of all starter

cultures showed a remarkable increase during production

and survival during storage.

Syneresis values of fermented milks ranged between 2.5and 3.0 ml for fresh products and decreased to 1.5 2.5 ml

after 20 days storage at 5C; the rate of decrease wasdependent on the starter culture used.

The firmness measurements of all fermented milksincreased over time, and the rate was independent

of the starter culture used; after the storage period, the

firmness values ranged between 1.8 and 2.5 N for the EPS

cultures MSKB 2 and ABT 1, respectively.

Sensory analysis indicated the following: (a) acid,creamy and=or other characters (for the odour, flavour

and after-taste attributes) were significant (P

Capron A, Cayuela C, Midtvedt T, Rowland I & de Vos W (eds) (2000):Mechanisms of Protection of the Digestive Tract. Nutrition and HealthCollection. Montrouge: John Libbey Eurotext.

Cerning J & Marshall VME (1999): Exopolysaccharides producedby the dairy lactic acid bacteria. Rec. Res. Microbiol. 3, 195 209.

Chandan RC (ed.) (1989): Yogurt Nutritional and Health Properties.Virginia: National Yogurt Association.

Chiang BL, Sheih YH, Wang LH, Liao CK & Gill HS (2000):Enhancing immunity by dietary consumption of a probioticlactic acid bacterium (Bifidobacterium lactis HN019): optimizationand definition of cellular immune responses. Eur. J. Clin. Nutr. 54,849 855.

Collins JK (2001): Demonstration of functional properties of probio-tic lactic acid bacteria. Ind. Latte 37, 39 61.

Dave RI & Shah NP (1997): Characteristics of bacteriocin producedby Lactobacillus acidophilus LA-1. Int. Dairy J. 7, 705 715.

Degeest B, Vaningelem F & de Vuyst L (2001): Microbial physiology,fermentation kinetics, and process engineering of heteropolysac-charide production by lactic acid bacteria. Int. Dairy J. 11,747 757.

Denariaz G, Dugas B, Kasper H, Schmucker D & Schrezenmier J (eds)(1999): Immunity and Probiotics. Nutrition and Health Collection.Montrouge: John Libbey Eurotext.

Desmazeaud M (1994): [Bacteriocins of lactic acid bacteria and theiruse in the dairy industry.] Rev. Med. Vet. 145, 711 720.

Duboc P & Mollet B (2001): Applications of exopolysaccharides inthe dairy industry. Int. Dairy J. 11, 759 768.

Dunne C, Murphy L, Flynn S, OMahony L, OHalloran S, Feeney M,Morrissey D, Thornton G, Fitzgerald G, Daly C, Kiely B, QuigleyEMM, OSullivan GC, Shanahan F & Kevin J (1999): Probiotics:from myth to reality demonstration of functionality in animalmodels of disease and in human clinical trials. Antonie van Leeu-wenhoek 76, 279 292.

FAO=WHO (1990): Codex Alimentarius Abridged Version, Joint FAO=WHO Food Standards Program Codex Alimentarius Commis-sion, ed. BL Smith. Rome: Food and Agricultural Organization ofthe United Nations.

Faras ME, Nupez de Kairuz M, Sesma F. Palacios J, de Ruz Holgado AP& Oliver G (1999): Inhibition of Listeria monocytogenes bythe bacteriocin enterocin CRL35 during goat cheese making.Milchwissenschaft 54, 30 32.

Fujiwara S, Hashiba H, Hirota T & Forstner JF (1999): Purification andcharacterization of a novel protein produced by Bifidobacteriumlongum SBT2928 that inhibits the binding of enterotoxigenicEscherichia coli Pb176 (CFA=II) to gangliotetraosylceramide.J. Appl. Microbiol. 86, 615 621.

Fuller R (ed.) (1992): Probiotics 1: The Scientific Basis. London:Chapman & Hall.

Fuller R (ed.) (1997): Probiotics 2: Applications and Practical Aspects.London: Chapman & Hall.

Fuller R & Perdigon G (eds) (2000): Probiotics 3: Immunomodul-ation by the Gut Microflora and Probiotics. Dordrecht: KluwerAcademic.

Ganzle MG, Holtzel A, Walter J, Jung G & Hammes WP (2000):Characterization or reutericyclin produced by Lactobacillus reuteriLTH2584. Appl. Environ. Microbiol. 66, 4325 4333.

Gibson GR & Angus F (eds) (2000): LFRA Ingredients Handbook:Prebiotics and Probiotics. Leatherhead: Leatherhead Food ResearchAssociation.

Gibson GR & Ruberfroid MB (1995): Dietary modulation ofthe human microbiota: introducing the concept of prebiotics.J. Nutr. 125, 1401 1412.

Gibson G, Heber D, Meydani S, Postaire E & Sanders ME (eds) (2000):Functional Dairy Products. Nutrition and Health Collection. Mon-trouge: John Libbey Eurotext.

Hamilton-Miller JMT (1999): Probiotics panacea or nostrum?Br. Nutr. Foundation Nutr. Bull. 21, 199 208.

Hamilton-Miller JMT & Gibson GR (1999): Efficacy studies ofprobiotics: a call for guidelines nutrition discussion forum.Br. J. Nutr. 82, 73 75.

Hartemink R (1999): Prebiotic Effects of Non-Digestible Oligo- and Poly-Saccharides. PhD Thesis, Landbouwuniversiteit Wageningen.Wageningen: Ponsen & Looijen.

Hartley D, Marcos A, Rosado J, Rubeglio E & Tannock G (2001):Fermented Foods and Healthy Digestive Functions. Montrouge: JohnLibey Eurotext.

Heyman M (2000): Effect of lactic acid bacteria on diarrheal diseases.J. Am. College Nutr. 19, 137s 146s.

Hirayama K & Rafter J (1999): The role of lactic acid bacteria in coloncancer prevention: mechanistic considerations. Antonie van Leeu-wenhoek 76, 391 394.

Hoier E (1992): Use of probiotic starter cultures in dairy products.Food Australia 44, 418 420.

Holzapfel WH, Geisen R & Schillinger U (1995): Biological preserva-tion of foods with reference to protective cultures, bacteriocinsand food-grade enzymes. Int. J. Food Microbiol. 24, 343 362.

Holzapfel WH, Schillinger U, du Toit M & Dicks L (1997): Systematicslactic acid bacteria with reference to modern phenotypic andgenomic methods. Microecol. Ther. 10, 1 10.

Holzapfel WH, Haberer P, Snel J, Schillinger U & Huis int Veld JHJ(1998): Overview of gut flora and probiotics. Int. J. Food Microbiol.41, 85 101.

IDF (1984): Fermented Milks, Bulletin no. 179. Brussels: InternationalDairy Federation.

IDF (1986): Production and Utilization of Ewes and Goats Milk, Bulletinno. 202. Brussels: International Dairy Federation.

IDF (1988): Fermented Milks Science and Technology, Bulletin no.227. Brussels: International Dairy Federation.

IDF (1992a): General Standard of Identity for Fermented Milks, Standardno. 163. Brussels: International Dairy Federation.

IDF (1992b): General Standard of Identity for Milk Products Obtainedfrom Fermented Milks Heat Treated After Fermentation, Standard no.164. Brussels: International Dairy Federation.

IDF (1992c): New Technologies for Fermented Milks, Bulletin no. 277.Brussels: International Dairy Federation.

IDF (1995): Heat-Induced Changes in Milk, ed. PF Fox, 2nd edn, SpecialIssue no. 9501. Brussels: International Dairy Federation.

IDF (1998): Texture of Fermented Milk Products and DairyDesserts. Special Issue no. 9802. Brussels: International DairyFederation.

IDF (2000): The World Dairy Situation, pp 45 53, Bulletin no. 355.Brussels: International Dairy Federation.

Jolly L & Stingele F (2001): Molecular organization and functionalityof exopolysaccharide gene cluster in lactic acid bacteria. Int.Dairy J. 11, 733 745.

Kar T (1999): Lactobacillus acidophilus as a dietary adjunct for milk toaid lactose digestion in lactose intolerance individuals. Environ.Ecol. 17, 351 355.

Kawai Y, Saito T, Suzuki M & Itoh T (1998): Sequence analysis bycloning of the structural gene of gassericin A, a hydrophobicbacteriocin produced by Lactobacillus gasseri LA39. Biosci.Biotechnol. Biochem. 62, 887 892.

Kawase M, Hashimoto H, Hosoda M, Morita H & Hosono A (2001):Effect of fermented milk with Streptococcus thermophilus TMC1543on serum lipid levels induced by high-cholesterol diet in adultsubjects. Milchwissenschaft 56, 496 499.

Klein G, Pack A, Bonaparte C & Reuter G (1998): Taxonomy andphysiology of probiotic lactic acid bacteria. Int. J. Food Microbiol.41, 103 125.

Kurmann JA (1984): Aspects of the production of fermented milks.In: Fermented Milks, pp 16 26, Bulletin no.179. Brussels: Interna-tional Dairy Federation.

Kurmann JA, Rasic JLj & Kroger M (1992): Encyclopedia of FermentedFresh Milk Products. New York: Van Nostrand Reinhold.

La Torre LR (1997): Some aspects of the production and quality offermented milks using bifidobacteria. PhD Thesis, University ofGlasgow, UK.

La Torre LR, Tamime AY & Muir DD (2002): Rheology and sensoryprofiling of set-type fermented milks made with different commer-cial bio and yoghurt starter cultures. Milchwissenschaft (in press).


S13


Lee Y-K, Nomoto K, Salminen S & Gorbach SL (1999): Handbook ofProbiotics. New York: John Wiley.

Lourens-Hattingh A & Viljoen BC (2001a): Growth and survival of aprobiotic yeast in dairy products. Food Res. Int. 34, 791 796.

Lourens-Hattingh A & Viljoen BC (2001b): Review: Yogurt as probio-tic carrier food. Int. Dairy J. 11, 1 17.

Maisnier-Patin S, Forni E & Richard J (1996): Purification, partialcharacterization and mode of action of enterococcin EFS2,an antilisterial bacteriocin produced by a strain of Enterococcusfaecalis. Int. J. Food Microbiol. 30, 255 270.

Malagelada J-R, Martinez A, Rafter J, Saviano D & Mateos JA (eds)(1999): Yoghurt: Eighty Years of Active Research for Health. Nutritionand Health Collection. Montrouge: John Libbey Eurotext.

Marshall VME & Tamime AY (1997a): Physiology and biochemistryof fermented milks. In: Microbiology and Biochemistry of Cheese andFermented Milk, 2nd edn, ed. BA Law, pp 153 192. London:Blackie Academic & Professional.

Marshall VME & Tamime AY (1997b): Starter cultures employed in themanufacture of biofermented milks. Int. J. Dairy Technol. 50, 35 41.

Marshall VME, Laws AP, Levander F, Radstrom V, de Vuyst L,Degeest B, Vaningelgem F, Dunn H & Elvin M (2001): Exopoly-saccharide-producing strains of thermophilic lactic acid bacteriacluster into groups according to their EPS structure. Lett. Appl.Microbiol. 32, 433 437.

Mattila-Sandholm T & Salminen S (1998): Up-to-date on probioticsin Europe. Gastroenterol. Int. 11 (Suppl 1), 8 16.

Mattila-Sandholm T, Matto J & Saarela M (1999a): Lactic acid bacteriawith health claims interactions and interference with gastroin-testinal flora. Int. Dairy J. 9, 25 35.

Mattila-Sandholm T, Blum S, Collins JK, Crittenden R, de Vos W,Dunne C, Fonden R, Grenov G, Isolauri E, Kiely B, Marteau P,Morelli L, Ouwehand A, Reniero R, Saarela M, Salminen S,Saxelin M, Schiffrin E, Shanahan F, Vaughan E & von Wright A(1999b): Probiotics: towards demonstrating efficacy. Trends FoodSci. Technol. 10, 393 399.

McAuliffe O, Ryan MP, Ross RP, Hill C, Breeuwer P & Abee T (1998):Lacticin 3147, a broad spectrum bacteriocin which selectivelydissipates the membrane potential. Appl. Environ. Microbiol. 64,439 445.

Meile L, Ludwig W, Rueger U, Gut C, Kaufmann P, Dasen G, Wenger S& Teuber M (1997): Bifidobacterium lactis sp. nov., a moderatelyoxygen tolerant species isolated from fermented milk. System.Appl. Microbiol. 20, 57 64.

Meisel H & Bockelmann W (1999): Bioactive peptides encrypted inmilk proteins: proteolytic activation and thropho-functionalproperties. Antonie van Leeuwenhoek 76, 207 215.

Metchnikoff E (1910): Prolongation of Life, revised edn of 1907, tran. CMitchell. London: Heinemann.

Meydani SN & Ha WH (2000): Immunologic effects of yogurt.Am. J. Clin. Nutr. 71, 861 872.

Monsan P, Bozonnet S, Albenne C, Joucla G, Willemont R-M &Remad-Simeon M (2001): Homopolysaccharides from lactic acidbacteria. Int. Dairy J. 11, 675 685.

Nes IF, Diep DB, Havarstein LS, Brurberg MB, Eijsink V & Holo H(1996): Biosynthesis of bacteriocins in lactic acid bacteria. Antonievan Leeuwenhoek 70, 113 128.

Oberhelman RA, Gilman RH, Sheen P, Taylor DN, Black RE, Cabrera L,Lescano AG, Meza R & Madico G (1999): A placebo-controlled trialof Lactobacillus GG to prevent diarrhea in undernourished Peru-vian children. J. Pediatr. 134, 15 20.

Oberman H & Libudzisz Z (1998): Fermented milks. In: Microbiologyof Fermented Foods, 2nd edn, ed. BJB Wood, pp 308 350. London:Blackie Academic & Professional.

Ouwehand AC, Kirjavainen PV, Shortt C & Salminen S (1999):Probiotics: mechanisms and established effects. Int. Dairy J. 9,43 52.

Papathanasopoulos MA, Dykes GA, Revol-Junel-Les AM, Delfour A,van Holy A & Hastings JW (1998): Sequence and structuralrelationships of leucocins A-, B- and C-TA33a from Leuconostocmesenteroides TA33a. Microbiology (Reading) 144, 1343 1348.

Pappas CP (1988): A comparative study of laws and regulations oncompositional requirements for yogurt in EC member states. Br.Food J. 90, 195 198.

Pederson CS (1979): Microbiology of Food Fermentations, 2nd edn, pp1 29. Connecticut: AVI Publishers.

Perdigon G, Fuller R & Raya R (2001): Lactic acid bacteria and theireffect on the immune system. Curr. Iss. Intest. Microbiol. 2, 27 42.

Rasic JLi & Kurmann JA (1978): Yoghurt Scientific Grounds, Technology,Manufacture and Preparations. Copenhagen: Technical DairyPublishing House.

Rasic JLi & Kurmann JA (1983): Bifidobacteria and their Role. Experi-entia Supplementum Vol. 39, pp 3 7. Basel: Birkhauser.

van Reenen CA, Dicks LMT & Chikindas ML (1998): Isolation,purification and partial characterization of plantaricin 423, abacteriocin produced by Lactobacillus plantarum. J. Appl. Microbiol.84, 1131 1137.

Reid G, Bruce AW, Fraser N, Heinemann C, Owen J & Henning B(2001): Oral probiotics can resolve urgogenital infections. Immu-nol. Med. Microbiol. 30, 49 52.

Remiger A, Eijsink VGH, Ehrmann MA, Sletten K, Nes IF & Vogel RF(1999): Purification and partial amino acid sequence of plantaricin1.25a and 1.25b, two bacteriocins produced by Lactobacillus plan-tarum TMW1.25. J. Appl. Microbiol. 86, 1053 1058.

Renard AC (1998): [Le marche en Europe: une nouvelle generation deprobiotique.] RLF 582, 24.

Rettger LF & Cheplin HA (1921): A Treatise on the Transformation ofthe Intestinal Flora with Special Reference to the Implantation ofBacillus acidophilus. New Haven: Yale University Press.

Rettger LF, Levy MN & Weinstein L (1935): Lactobacillus acidophilusand its Therapeutic Application. New Haven: Yale University Press.

Richard JA (1996): Use of bacteriocin producing starters advanta-geously in dairy industry. In: Lactic Acid Bacteria: Current Advancesin Metabolism, Genetics and Applications, ed. TF Bozoglu & B Ray,pp 137 154. Berlin: Springer.

Robinson RK (ed) (1991): Therapeutic Properties of Fermented Milks.London: Elsevier Applied Science.

Robinson RK & Tamime AY (1976): Quality appraisal of yoghurt.J. Soc. Dairy Technol. 29, 148 155.

Robinson RK & Tamime AY (1990): Microbiology of fermented milks.In: Dairy Microbiology, 2nd edn, Vol. 2, ed. RK Robinson,pp 291 343. London: Elsevier Applied Science.

Salminen S (2001): Human studies on probiotics: aspects of scientificdocumentation. Scand. J. Nutr. 45, 8 12.

Salminen S & von Wright A (eds) (1998): Lactic Acid Bacteria, 2ndedn. New York: Marcel Dekker.

Salminen S, Isolauri, E & Salminen E (1996a): Clinical usesof probiotics for stabilizing the gut mucosal barrier: successfulstrains for future challenge. Antonie van Leeuwenhoek 70, 347 358.

Salminen S, Laine M, von Wright A, Vuopio-Varkila J, Korhonen T &Mattila-Sandholm T (1996b): Development of selection criteriafor probiotic strains to assess their potential in functional foods: aNordic and European approach. Biosci. Microflora 15, 61 67.

Salminen S, Ouwehand AC & Isolauri E (1998a): Clinical applicationof probiotic bacteria. Int. Dairy J. 8, 563 572.

Salminen S, Bouley C, Boutron-Ruault M-C, Cummings JH, Franck A,Gibson GR, Isolauri E, Moreau M-C, Roberfroid M & Rowland I(1998b): Functional food science and gastrointestinal physiologyand function. Br. J. Nutr. 80 (Suppl 1), S147 S171.

Salminen S, von Wright A, Morelli L, Marteau P, Brassart D,de Vos WM, Fonden R, Saxelin M, Collins K, Mogensen G,Birkeland S-E & Mattila-Sandholm T (1998c): Demonstrationof safety of probiotics: a review. Int. J. Food Microbiol. 44, 93 106.

Sanders ME (1994): Lactic acid bacteria as promoters of humanhealth. In: Functional Foods, ed. I Goldberg, pp 294 322. NewYork: Chapman & Hall.

Sanders ME & Huis int Veld J (1999): Bringing a probiotic-containingfunctional food to the market: microbiological, product, regulatoryand labeling issues. Antonie van Leeuwenhoek 76, 293 315.

Shortt C (1997): Innovative ingredients for optimum gut health. Eur.Food Drink Rev. Winter, 31 35.


S14


Shortt C (1999): The probiotic century: historical and current per-spectives. Trends Food Sci. Technol. 10, 411 417.

Suma K, Misra MC & Varadaraj MC (1998): Plantaracin LP84, a broadspectrum heat-stable bacteriocin of Lactobacillus plantarum NCIM2084 produced in a simple glucose broth medium. Int. J. FoodMicrobiol. 40, 17 25.

Tamime AY (1998): [Tendenze del consumo Europeo di prodottiprobiotici a base di latte fermentato.] Latte 23 (1), 52 59.

Tamime AY (2002): Microbiology of starter cultures. In: Dairy Micro-biology, 3rd edn, Vol. 2, ed. RK Robinson. New York: John Wiley &Sons.

Tamime AY & Marshall VME (1997): Microbiology and technology offermented milks. In: Microbiology and Biochemistry of Cheese andFermented Milk, 2nd edn, ed. BA Law, pp 57 152. London: BlackieAcademic & Professional.

Tamime AY & Robinson RK (1999): Yoghurt Science and Technology,2nd edn, pp 261 366. Cambridge: Woodhead Publishing.

Tamime AY, Marshall VME & Robinson RK (1995): Microbiologicaland technological aspects of milks fermented by bifidobacteria.J. Dairy Res. 62, 151 187.

Tamime AY, Robinson RK & Latrille E (2001): Yoghurt and otherfermented milks. In: Mechanisation and Automation in Dairy Tech-nology, ed. AY Tamime & BA Law, pp 152 203. Sheffield: SheffieldAcademic Press.

Tannock GW (ed) (1999): Probiotics A Critical Review. Wymond-ham: Horizon Scientific Press.

Volpe R, Niittynen L, Korpela R, Sirtori C, Bucci A, Fraone N &Pazzucconi F (2001): Effects of yoghurt enriched with plant sterolson serum lipids in patients with moderate hypercholesterolaemia.Br. J. Nutr. 86, 233 239.

de Vuyst L & Vandamme EJ (eds) (1994): Bacteriocins of Lactic AcidBacteria. London: Blackie Academic & Professional.

de Vuyst L, de Vin F, Vaningelgem F & Degeest B (2001): Recentdevelopments in the biosynthesis and applications ofheteropolysaccharides from lactic acid bacteria. Int. Dairy J. 11,687 707.

Wszolek M, Tamime AY, Muir DD & Barclay MNI (2001): Properties ofKefir made in Scotland and Poland using bovine, caprine andovine milk with different starter cultures. Lebensm.- Wiss. u.Technol. 34, 251 261.

Yildirim Z & Johnson MG (1998): Characterization and antimicrobialspectrum of bifidocin B, an bacteriocin produced by Bifidaobacter-ium bifidum NCFB 1454. J. Food Protec. 61, 47 51.

Zhu WM, Liu W & Wu DQ (2000): Isolation and characterization of anew bacteriocin from Lactobacillus gasseri KT7. J. Appl. Microbiol.88, 877 886.


S15


Date post:	08-Jan-2016
Category:	Documents
Upload:	sawang-loy-r-kart
View:	219 times
Download:	0 times

1601657 A

Documents