Milk products. Enumeration of presumptive Lactobacillus acidophilus on a selective medium. Colony-count technique at 37°C

2007 ◽  
1980 ◽  
Vol 84 (2) ◽  
pp. 191-202 ◽  
Author(s):  
R. A. E. Barrell ◽  
M. G. M. Rowland

SUMMARYTwo commercially available baby milks, one ‘biologically acidified’, the other ‘non-acidified’, and a traditional weaning food, millet gruel, were prepared and stored under village conditions in West Africa. Increases in total colony count and in number ofBacillus cereus, Clostridium welchii, Staphylococcus aureusandEscherichia coliwere determined in these products when stored as commonly practised at ambient temperatures over a period of 8 h. Poor hygiene during preparation was indicated by readily detectable numbers of coliforms andE. coliin freshly prepared samples of each of the milks, though the cooked local gruel seemed less vulnerable in this respect. The rate of increase in the numbers of these organisms was lower in the acidified milk when prepared with unboiled water containing high numbers of coliforms andE. coli. Increases in total colony count and in numbers ofStaph. aureuswere also less marked in the acidified milk. When food was not eaten soon after preparation the problem of bacterial overgrowth was as great with the local gruel as with the considerably more nutritious reconstituted milks.


Author(s):  
Barun K Bhattacharyya ◽  
S Chowdhury ◽  
S Das ◽  
P K Saha ◽  
S Mukherjee ◽  
...  

Probiotic microorganisms have been utilized for many years in food processing, preservations and for nutraceutical health benefits.  There are a large number of pharmaceutical formulations containing probiotic microorganisms available in the market worldwide. Majority of these organisms are the members specifically from genera Lactobacillus, Lactococcus and Bifidobacterium. A number of media have been proposed for selective or differential enumeration of lactobacilli and bifidobacteria in mixed populations. The development of selective medium using different types of ingredients and antibiotic are well practiced. In the present study we have developed a selective medium for the enumeration of Lactobacillus acidophilus by utilizing the antibiotic ofloxacin resistance of the organism in Lactobacilli MRS-agar. Samples were analyzed by determining viable counts in reference Lactobacilli MRS agar and selective Lactobacilli MRS-ofloxacin agar media. The results were statistically analyzed to evaluate the precision, accuracy, reproducibility and selectivity of the method developed.  Thus MRS containing ofloxacin medium can be used for selective enumeration of Lactobacillus acidophilus strains available in commercial formulations containing Bifidobacterium species.


2021 ◽  
pp. 36-39
Author(s):  
Ирина Владимировна Рожкова ◽  
Анна Васильевна Бегунова ◽  
Юлия Игоревна Крысанова

Кисломолочные продукты приобретают популярность во всем мире благодаря их полезным и функциональным свойствам. Проблема разработки и широкого использования кисломолочных продуктов приобретает огромное значение в период пандемии и экологического кризиса. Полезные свойства кисломолочных продуктов зависят от состава заквасок, используемых для их производства. Вид и количество используемых в составе закваски штаммов обуславливает бифункциональный эффект пробиотического кисломолочного продукта. Из молочнокислых бактерий Lactobacillus являются наиболее изученными пробиотическими микроорганизмами с широким спектром физиолого-биохимических свойств. Для разработки кисломолочного продукта была использована ассоциация заквасочных культур, состоящая из Lactobacillus rhamnosus TR, Lactobacillus reuteri LR1 и Lactobacillus acidophilus H-9 в соотношении 1:6:1, которая обладает функциональным потенциалом. В работе научно обоснованы технологические режимы производства пробиотического кисломолочного продукта c использованием указанной выше ассоциации культур, которая обеспечивает сквашивание пастеризованного обезжиренного молока за 7-8 ч при внесении 5-7 % инокулята, обеспечивая определенные органолептические показатели. При этом количество клеток пробиотических культур составляет для L. acidophilus Н-9 1,1×10 КОЕ/см, для L. reuteri LR 1 (2,1±1,3)×10КОЕ/см, для L. rhamnosus TR (1,37±0,98)×10 КОЕ/см. Показано, что разработанный кисломолочный продукт обладает антагонистической активностью к S. aureus АТСС 6538 и Salmonella typhimurium NCTC 00074, а также антиоксидантной и АПФ-ингибирующей активностью, что характеризует его бифункциональные свойства. Диаметр зоны ингибирования роста S. aureus АТСС 6538 составляет 15,25±0,35 см, а Salmonella typhimurium NCTC 00074 10,5±0,71 см. Антиоксидантная активность разработанного продукта составляет 570,64±18 мкмоль TЭ/мг, а АПФ ингибирующая активность - IC 1,23±1,6 мг белка/см. Fermented milk products are gaining popularity all over the world due to their useful and functional properties. The problem of the development and widespread use of fermented milk products becomes of great importance during a pandemic and an ecological crisis. The beneficial properties of fermented milk products depend on the composition of the starter cultures used for their production. The type and quantity of strains used in the starter culture determine the bifunctional effect of the probiotic fermented milk product. Of the lactic acid bacteria, Lactobacillus is the most studied probiotic genus with a wide range of physiological and biochemical properties. For the development of a fermented milk product, an association of starter cultures was used, consisting of Lactobacillus rhamnosus TR, Lactobacillus reuteri LR1, and Lactobacillus acidophilus H-9 in a ratio of 1: 6:1, which has a functional potential. The work scientifically substantiates the technological modes of production of a probiotic fermented milk product using the above-mentioned association of cultures, which ensures the fermentation of pasteurized skim milk in 7-8 hours with the introduction of 5-7 % inoculum, providing certain organoleptic characteristics. In this case, the cells number of probiotic cultures for L. acidophilus H-9 is 1.1×10 CFU/cm, for L. reuteri LR 1 (2.1±1.3)×10 CFU/cm, for L. rhamnosus TR (1.37±0.98)×10 CFU/cm. It was shown that the developed fermented milk product has an antagonistic activity to S. aureus ATCC 6538 and Salmonella typhimurium NCTC 00074, as well as antioxidant and ACE-inhibiting activity, which characterizes its bifunctional properties. The diameter of the growth inhibition zone for S. aureus ATCC 6538 is 15.25±0.35 cm and for Salmonella typhimurium NCTC 00074 10.5±0.71 cm. The antioxidant activity of the developed product is 570.64±18 μmol TE/mg, and ACE inhibitory activity IC50 1.23±1.6 mg protein/cm.


2020 ◽  
Vol 4 ◽  
pp. 3-7
Author(s):  
Yana Biletska ◽  
Galina Dyukareva ◽  
Natalia Danko

The results of using flour of sprouted soya and chickpea at making sour-milk products, based on goat milk, are presented. The object of the study is sour milk products, based on goat milk with using flour of sprouted leguminous, enriched with iodine and selenium with the associated use of acidophilic baccilus Lactobacillus acidophilus and bifidobacteria Bifidobacterium lactis. One of today problems is a deficiency of iodine and selenium, coming to the human organism with food in organically available forms. In this connection the development of new sour-milk products that are carriers of organic forms of microelements with organoleptic characteristics, usual for consumers, is an important task. At the research the dependence of changes of organoleptic parameters of sour-milk product quality has been established. It has been determined, that it is expedient to use flour, enriched with iodine and selenium in amount 2 % of the sour-milk product mass. Introduction of the aforesaid amount of flour in a sour-milk product favors the improvement of organoleptic parameters and gives developed products a special dietetic destination. At consuming 100 g of a sour-milk vegetable product, 16.8 and 24.5 % of the daily need in iodine and selenium (respectively) is covered. Based on the obtained results, the recipe of a sour milk product that provides the use of goat milk in amount 93 %, flour of sprouted leguminous (1:1) in amount 2 %, acidophilic bacillus Lactobacillus acidophilus and bifidobacteria Bifidobacterium lactis in amount 5 % of the product mass has been elaborated. Comparing with analogous known methods, the offered method provides a series of advantages. The most important of them are organoleptic parameters of a ready product, usual for consumers, and its safe enrichment with iodine and selenium. It takes place at the expanse of using organic forms of microelements that excludes a possibility of accumulation in the organism


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