STARTER CULTURES AND FERMENTED MILK PRODUCTS

 

Module 15. Probiotics, acidophilus and bifidus milk products

Lesson 28
ACIDOPHILUS AND BIFIDUS PRODUCTS

28.1 Introduction

Several products containing live lactobacilli or bifidobacteria have been developed in various forms using milk as the base material or by supplementation of cereals, oats, fruits, vegetables and other juices. Certain products are strictly hygienically made and prescribed by medical professionals for specific ailments

28.2 Acidophilus Products

28.2.1 Sour acidophilus milk

Acidophilus milk is a sour product that has been allowed to ferment under conditions that favour the growth and development of a large number of Lactobacillus acidophilus organisms. This acidophilus milk is considered as a probiotic since it aids in the well being of the consumer. Acidophilus milk differs from Indian dahi or curd in body, texture, consistency, flavour, chemical composition and in antibacterial activities.

28.2.2 Sweet acidophilus milk

As natural fermented acidophilus milk was sour and having medicinal type of flavour, it was thought appropriate to sell as non-fermented milk. This gave birth to sweet acidophilus milk. It is probiotic dairy product based on unfermented milk. It is produced by adding concentrated probiotic bacteria to intensively heat treated and chilled milk. Heat treatment is necessary to achieve sufficient microbiological stability during storage of the final product.

In some cases it is also prepared by adding concentrated cells of Lb. acidiophilus in chilled pasteurized milk.

28.2.3 Acidophilus yoghurts

Yoghurt is a popular product in many parts of the world. Many probiotic products have been developed taking yoghurt as a base. In some products, acidophilus or other probiotic bacteria are added as a supplement or in other cases one of the yoghurt culture is replaced by Lb. acidophilus.

The acidophilus yoghurt produced from cow milk is popular in Germany, USA, Scandinavia, Australia, and many other countries,. It is believed that human intestinal strains of acidophilus culture increase the beneficial value of the yoghurt made with them. The starter culture consists of yoghurt culture (Streptococcus thermophilus and Lactobacillus delbruckii subsp. bulgaricus) and Latobacillus acidophilus.

A product known as ACO-Yoghurt is also reported from Switzerland and U.K with improved dietetic and therapeutic values of the yoghurt. The starter cultures consist of yoghurt culture and culture of an intestinal strain of Lb. acidophilus,

28.2.4 Acidophilus bifidus yoghurt

This product is very popular in Germany, United States, Japan and several other countries, obtained from cow milk. The product was first manufactured in Germany in order to improve the nutritive as well as the therapeutic value of yoghurt. The products involve three groups of bacteria, a. Yoghurt culture (Streptococcus thermophilus and Lactobacillus delbruckii subsp. bulgaricus), b. Strains of Lb. acidophilus and c. Bifidobacterium bifidum or B. longum.

The final product is expected to contain 10⁷ per ml each of Lb. acidophilus and B. bifidum and large numbers of Yoghurt organisms.

28.2.5 Acidophilin

It is the product originated from the USSR, obtained from cow’s milk which is set or stirred, flavor may vary from mild to acid depending on the quality of starter culture. The principle of processing is mixed acid and alcoholic fermentation involving Lb. acidophilus, Lb. lactis subsp. lactis or Lb. delbruckii subsp bulgaricus and Kefir culture) at the rate of 6 – 9 %.

28.2.6 Acidophilus cream

The product has originated from Czechoslovakia, obtained from cream of cow milk. The cultures involved is Lb. acidophilus. The process involves cream with 40 – 45 % fat, which is homogenized, pasteurized, added with sugar syrup and then inoculated with the culture of Lb. acidophilus.

28.2.7 Acidophilus ice cream

Ice cream is one of the most popular dairy products and probiotics can be easily dispensed through this medium. The acidophilus ice cream finds its origin from USA. It is prepared with a mix added with concentrated Lb. acidophilus culture (10⁹ per ml) and frozen.

Now several reports are available wherein the study of viability of Lb. acidophilus in ice cream has been studied. Recently, Amul launched ‘Prolife’, a probiotic icecream containing Lactobacilli and Bifidobacteria.

28.2.8 Acidophilus yeast milk

The manufacture of the product using the culture Lb. acidophilus and lactose fermenting yeast was mainly for the therapy of the gastrointestinal disorders and tuberculosis. The viability of the acidophilus bacteria is expected to improve when they are grown together with yeasts. The product has a final acidity of 0.8-1.0% and contains about 0.5% ethanol in addition to carbon dioxide.

28.3 Bifidus Products

28.3.1 Bifidus milk

The product finds its origin from Germany. The product is named accordingly to the bacteria used in fermentation. Bifidobacteria sp are the predominant intestinal flora and the major components of large intestine of human adults. Bifidus milk is produced in small quantities in some of the European countries. The consumption is linked to the dietetic and therapeutic values rather than the sensory properties. However, as Bifidobacteria ferment milk producing more of acetic acid than lactic acid, it has a vinegar like flavour and people do not enjoy it as a food. It remained a product to be used for therapeutic purposes. Further, Bifidobacteria are anaerobic in nature and hence it is very difficult to grow them in milk.

28.3.2 Bifidus baby foods

Several formulations containing Bifidobacteria are in the market intended for use as baby foods or infant food formulae. The product aims to increase the population of bifidobacteria in intestinal tract.

Some of the commercial baby foods are

· The dried formulae product called Lactana – B, containing lactulose and viable B. bifidum, produced from modified milk.

· The liquid formulae product called Bifiline, containing viable Bifidobacteria, first developed by the Russians in 1982. It is made by using milk formulae called Malutka (Acidophilus baby foods) and selected strain of Bifidobacteria.

· The dried formulae product called Femilect, containing viable Bifidobacteria, which was developed in Czechoslovakia in 1984, made by fermenting heat treated cream (12% fat) with mixed culture consisting of B. bifidum, Lb. acidophilus and P. acidilactici. The final product when reconstituted has 28°Th (0.25% T.A) and contains 10⁸-10⁹ / ml viable culture bacteria.

28.3.3 Bifidus yoghurt

The product is made with yoghurt cultures supplemented selected cultures of Bifidobacterium bifidum or B. longum. The product is made either by simultaneous fermentation or by mixing into cultured yoghurt separately cultured bifidus milk at a desirable ratio.

28.3.4 Bifighurt

This is a commercial product from Germany. The starter culture used in this product is Bifidobacterium longum C KL 1969 of B. longum and S. thermophilus. The final product contains 95% L (+) lactic acid and about 10⁷ bifidobacteria per ml.

28.3.5 Biogarde ^R

This product also is from Germany, known for its mild acidic taste and flavor. The manufacturing procedure of the product was developed by Bioghurt^R Company in Germany. The Biogarde^RLactobacillus acidophilus, Bifidobacterium longum and Streptococcus thermophilus. Biogarde^R produces fermented milk as well as icecream. culture contains

28.3.6 Biokys

The technology of biokys as a health product was developed in Czechoslovakia, where the product is commercially produced. It is a cultured sour cream like beverage obtained by fermenting milk with a mixed culture of bifidobacteria, acidophilus bacteria, and Pediococcus acidilactici.

Brief information about milk based acidophilus-bifidus products is given in Table 28.1, while non-milk based products are delineated in Table 28.2. The commercially available probiotic products are listed in the Table 28.3.

Table 28.1 Milk based acidophilus/bifidus products

Name	Physical Type	Country of Origin	Microflora
Fermented acidophilus	Gel	Most Countries	Lactobacillus acidophilus
Sweet acidophilus	Liquid	USA	Lactobacillus acidophilus
Nu Trish a/ B	Liquid	USA	Lb. acidophilus + Bifidobacteria species
A- 38 Fermented milk	Liquid	Denmark	Lb. acidophilus + Mesophilic lactic culture
Acidophilus Yoghurt	Gel	Most Countries	Lb. acidophilus + S. thermophilus and Lb. bulgaricus
ACO-Yoghurt	Gel	Switzerland	Lb. acidophilus + S. thermophilus and Lb. bulgaricus
Cultura	Liquid	Denmark	Lb. acidophilus + B. bifidum
AB – Yoghurt	Gel	Denmark	Lb. acidophilus + B. bifidum + Yoghurt culture.
Biograde	Liquid	---	Lb. acidophilus + B. bifidum, S. thermophilus
Bifighurt	Gel	FRG	Lb. acidophilus + S. thermophilus, B. bifidum
Mil – mil E	Gel	---	Lb. acidophilus + B. bifidum + Yoghurt culture
Miru-Miru	Liquid	Japan	Lb. acidophilus + L. Casei, B. breve,
Yakault	Liquid	---	L. casei
Smetara	Liquid/Gel	Eastern Europe	Lb. acidophilus + S. lactis subsp. diacetylactis
Zdorov E.(+ malt extract)	Liquid	USSR	Kefir culture
Kefir	Liquid	Most Countries	Lb. delbruckii subsp. bulgaricus, S. thermophilus, S. lactis, Leuconostoc sp, S. cerevisiae
Biogarde Ice Cream	Frozen	FRG	Lb. acidophilus + B. bifidum
Big M (Cheese Whey)	Liquid	FRG	Lb. acidophilus

Table 28.2 Non milk based acidophilus/bifidus probiotic products

Soyyo	Gel	USA	Lb. acidophilus + Lb. delbruckii subsp. bulgaricus, S. thermophilus
Lupinseed	Gel	Korea	Lb. acidophilus + S. thermophilus, Leuconostoc mesenteroides subsp. mesenteroides, , Lb. casei, L. lactis
Matsoni	Liquid /Gel	Eastern European	Lb. acidophilus + S. thermophilus
Smetana	Liquid /Gel	---	Lb. acidophilus + S. thermophilus
Tvorog	Liquid /Gel	---	Lb. acidophilus + S. faecalis, L. fermentum
Suluguni Cheese	Solid	---	Lb. acidophilus + S. thermophilus
Prostokoasha	Liquid /Gel	---	Lb. acidophilus + S. thermophilus
Ryazhenka	Liquid /Gel	---	Lb. acidophilus + S. thermophilus, Lb. delbruckii subsp. lactis
Sourdough	Solid	FRG	Lb. acidophilus + Lb. farciminis, yeast species mixture
Recombined milk (NFDM + anhydrous milk fat)	Liquid /Gel	UK	Lb. acidophilus
Soy protein concentrate	Liquid /Gel	Korea	Lb. acidophilus + Yoghurt culture
Soy flour plus WPC	Liquid /Gel	Italy	Lb. acidophilus + Yoghurt culture, B. bifidum

Table 28. 3 Therapeutic acidophilus/bifidus products used as probioitics in market

Strain of the Organism	Company
Lb. acidophilus La 5	Chr. Hansen
Lb. acidophilus NCFM	Rhodia
Lb. casei Shirota	Yakult
Lb. acidophilus Johnsonii La1	Nestle
Lb. plantarum 299v	Probi
Lb. reuteri MM2	Biogaia
Lb. rhamnosus GG	Valio
B. longum BB-536	Morinaga Milk Industry
B. longum SBT-2928	Snow Brand Milk Products
B. breve	Yakult
B. lactis LaftiTM B94	DSM
B. longum UCC35624	UCC Cork
B. lactis DR-10/Howaru	Danisco

28.4 Probiotic Cheeses

Success in the use of probiotic bacteria with fermented liquid milk products has inspired the development of other dairy products with probiotics. The production of cheeses, especially the ripened types, with probiotic bacteria presents unique challenges because of the need for co-survival of these bacteria with the conventional lactic acid bacteria, mould or yeasts that are used for cheese making. These micro-organisms may be antagonistic, competitive or symbiotic towards each other. Some key characteristics of cheeses/cheese making that are relevant to the inclusion of probiotics are; (1) Relative low moisture content; (2) Presence of salt (3) Starter culture organisms; (4) Extended storage over 3 months, which can influence the biochemical activities, alteration of redox potential and re-organisation of the cheese structure.

Various cheese varieties have been successfully used as carriers of probiotic microorganisms. Some cheeses may be particularly suitable for the delivery of probiotic bacteria relative to fermented milks such as yoghurt, because of lower acidity and the existence of a complex cheese matrix of protein and fat that will provide protection to probiotic microorganisms during their passage through the gastrointestinal tract. Studies have demonstrated that Turkish white brined, Feta-type, Cheddar, Philippine white soft, Edam, Emmental, Domiati, Ras, soft, Herrgård cheeses, Quarg, and cheese-based dips compare favourably with yoghurt as delivery systems for viable probiotic micro-organisms. Probiotic bacteria may be introduced into cheese as adjunct cultures along with the lactic starter cultures. The introduction of probiotic organisms along with lactic starter cultures directly into milk prior to cheese making raises the risk of losing large numbers of the probiotic cells to whey or domination by lactic starter culture. This can particularly be a problem with slow-growing probiotic bacteria, but with proper strain selection the method has been used successfully. Microencapsulation may be used to protect probiotic organisms and improve viability and encapsulated B. bifidum, B. infantis and Bifidobacterium longum have been used in the manufacture of Crescenza cheese. Another method of introduction, particularly into semi-hard and hard cheeses, is through the addition of a dried culture during salting of curd, as is done with some accelerated ripening enzyme preparations. This method minimises the losses of bacterial cells to whey and eliminates the effects of competition with lactic acid bacteria during milk ripening.