BEHAVIOR OF SALMONELLA TYPHIMURIUM IN SKIMMILK DURING FERMENTATION BY LACTIC ACID BACTERIA1

1972 ◽  
Vol 35 (8) ◽  
pp. 482-488 ◽  
Author(s):  
H. S. Park ◽  
E. H. Marth
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Salmonella Typhimurium ◽  
Streptococcus Thermophilus ◽  
Mixed Cultures ◽  
Lactobacillus Bulgaricus ◽  
Complete Inactivation ◽  
Streptococcus Lactis ◽  
Streptococcus Cremoris ◽  
Incubation Temperatures

Skimmilk was inoculated with Salmonella typltimurium (approximately 103/ml) and with Streptococcus cremoris, Streptococcus lactis, mixtures of S. cremoris and S. lactis, Streptococcus diacetilactis, Streptococcus thermophilus, Lactobacillus bulgaricus, mixtures of S. thermophilus and L. bulgaricus, a mixture of L. helveticus and S. thermophilus, and Leuconostoc citrovorum. Inocula of lactic acid bacteria ranged from 0.25 to 5.0% and incubation temperatures from 21 to 42 C. Streptococcus cremoris, S. lactis, and mixtures of the two repressed growth but did not inactivate S. typhimurium during 18 hr of incubation at 21 or 30 C when the lactic inoculum was 0.25%. An increase in inoculum to 1% resulted in inactivation of S. typhimurium at 30 C by some of the mixed cultures. Both S. diacetilactis and L. citrovorum were less inhibitory to S. typhimurium than were S. cremoris or S. lactis. When added at the 1% level, Streptococcus thermophilus was more detrimental to S. typhimurium at 42 C than was L. bulgaricus. Mixtures of these two lactic acid bacteria, when added at levels of 1.0 and 5.0%, caused virtually complete inactivation of S. typhimurium during the interval between 8 and 18 hr of incubation at 42 C.

SURVIVAL OF SALMONELLA TYPHIMURIUM IN REFRIGERATED CULTURED MILKS1

1972 ◽  
Vol 35 (8) ◽  
pp. 489-495 ◽  
Author(s):  
H. s. Park ◽  
E. H. Marth
Keyword(s):  
Lactic Acid ◽  
Citric Acid ◽  
Lactic Acid Bacteria ◽  
Salmonella Typhimurium ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Helveticus ◽  
Lactobacillus Bulgaricus ◽  
Refrigerated Storage ◽  
Streptococcus Lactis ◽  
Pure Cultures

Cultured skimmilks containing Salmonella typhimurium were prepared at 21, 30, or 42 C using different species of lactic acid bacteria (0.25, 1.0, and 5% inoculum) either singly or in combinations. Several commercial cultures also were used. Cultured skimmilks were stored at 11 C and tested at 3-day intervals for numbers of viable salmonellae and lactic acid bacteria and for pH. Survival of S. typhimurium varied from 6 to 9 days and from 3 to 6 days in milks cultured with 0.25% Streptococcus lactis at 21 and 30 C, respectively. Increasing the inoculum to 1% with incubation at 30 C yielded a product no more detrimental to S. typhimurium than when the lower inoculum was used at 30 C. Survival of S. typhimurium always exceeded 9 days when S. cremoris was used to make cultured skimmilks. Products made with commercial mixed cultures composed of S. lactis and S. cremoris allowed S. typhimurium to survive for periods intermediate between the extremes observed when pure cultures were used. Skimmilks cultured with Streptococcus diacetilactis and Leuconostoc citrovorum, even when skimmilks cultured with the latter organism were acidified with citric acid and incubated further, were essentially without effect on survival of S. typhimurium during refrigerated storage. Use of Streptococcus thermophilus (1% culture, 42 C incubation) yielded cultured skimmilks that were most detrimental to survival of salmonellae, whereas skimmilks fermented with Lactobacillus bulgaricus permitted survival of low numbers of salmonellae beyond 9 days. Milks cultured at 42 C with a 5% inoculum of S. thermophilus mixed with L. bulgaricus or Lactobacillus helveticus were free of viable salmonellae before the incubation was complete. Salmonellae grown in skimmilk at 21 C without a lactic culture were more resistant to inactivation during refrigerated storage than was S. typhimurium grown at 30 or 42 C.

Preservation of Lactic Acid Bacteria on Anhydrous Silica Gel for Three Years

1983 ◽  
Vol 46 (8) ◽  
pp. 699-701 ◽  
Author(s):  
MARIA C. T. DE SILVA ◽  
MARIA A. TESSI ◽  
MARIA A. MOGUILEVSKY
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Silica Gel ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Helveticus ◽  
Lactobacillus Bulgaricus ◽  
Preservation Methods ◽  
Streptococcus Lactis ◽  
Streptococcus Cremoris ◽  
Negative Effect

This study, which covers three years of storage. analyzes the application of silica gel preservation methods to lactic acid bacteria widely used in yogurt and cheese fermentation. Strains of Streptococcus lactis, Streptococcus lactis subsp. diacetylactis, Streptococcus cremoris, Streptococcus thermophilus. Lactobacillus bulgaricus, Lactobacillus helveticus and a yogurt culture were adsorbed on anhydrous silica gel in screw-cap tubes or in ordinary test tubes which were subsequently flame-sealed under vacuum. During 3 years. the bacteria were tested for viability by incubation in sterile milk. All of the bacteria retained their acidifying activity, with the exception of the yogurt culture. Extending preservation for more than 2 years had a negative effect on the activity of the yogurt culture. Results obtained support the use of screw-cap tubes which, in general, were suitable to preserve suspensions of lactic acid bacteria adsorbed on anhydrous silica gel.

Lactic Acid Production in Milk Containing Cleaning or Sanitizing Compounds

1984 ◽  
Vol 47 (3) ◽  
pp. 197-199 ◽  
Author(s):  
MICHAEL B. LIEWEN ◽  
ELMER H. MARTH
Keyword(s):  
Lactic Acid ◽  
Ammonium Chloride ◽  
Acid Production ◽  
Lactic Acid Production ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Bulgaricus ◽  
Titratable Acid ◽  
Streptococcus Lactis ◽  
Streptococcus Cremoris ◽  
Dry Milk

Sterile reconstituted nonfat dry milk containing 0.1% (v/v) each of 19 cleaning or sanitizing compounds intended for use on dairy farms or in milk factories was inoculated with Streptococcus lactis 4175, Streptococcus cremoris C-13, Streptococcus thermophilus ST4 or Lactobacillus bulgaricus. Milk then was incubated at 32°C for 12 h and pH and titratable acid were determined. Five products (alkaline inflation cleaner, hypochlorite sanitizer-farm use, isopropanol udder wash, ammonium chloride detergent-factory use, alkaline cleaner A-factory use) were inhibitory to at least three of the four lactic acid bacteria at the 0.1% concentration. These were then tested at 0.050, 0.025, 0.012 and 0.006% concentrations. Of the five products, only the isopropanol udder wash (at all four concentrations) inhibited S. lactis and S. cremoris. The isopropanol udder wash at all four concentrations and the ammonium chloride cleaner at 0.050% inhibited L. bulgaricus. S. thermophilus was inhibited by the isopropanol udder wash at 0.050%, whereas the alkaline cleaner A-factory use, at 0.050 and 0.025%, may have been mildly stimulatory to acid production by this bacterium.

Behavior of Listeria monocytogenes in Skim Milk during Fermentation with Mesophilic Lactic Starter Cultures

1988 ◽  
Vol 51 (8) ◽  
pp. 600-606 ◽  
Author(s):  
MICHELLE M. SCHAACK ◽  
ELMER H. MARTH
Keyword(s):  
Lactic Acid ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Skim Milk ◽  
Starter Cultures ◽  
Plate Count ◽  
Inoculum Level ◽  
Plate Count Agar ◽  
Streptococcus Lactis ◽  
Streptococcus Cremoris

The ability of Listeria monocytogenes to grow and compete with mesophilic lactic acid bacteria was examined. Autoclaved skim milk was inoculated with 103 cells of L. monocytogenes (strain V7 or Ohio)/ml, and with 5.0, 1.0, 0.5 or 0.1% of a milk culture of either Streptococcus cremoris or Streptococcus lactis. Inoculated milks were fermented for 15 h at 21 or 30°C, followed by refrigeration at 4°C. Samples were plated on McBride Listeria Agar to enumerate L. monocytogenes and on either APT Agar or plate count agar to enumerate lactic acid bacteria. L. monocytogenes survived in all fermentations, and commonly also grew to some extent. Incubation at 30°C with 5% S. lactis as inoculum appeared to be the most inhibitory combination for strain V7, causing 100% inhibition in growth based on maximum population attained. S. cremoris at the 5.0% and 0.1% inoculum levels, was slightly less inhibitory to L. monocytogenes at 37°C, but it was slightly more inhibitory to L. monocytogenes at the 1.0% inoculum level than was S. lactis. In general, S. lactis reduced the pH of fermented milks more than did S. cremoris. The population of L. monocytogenes began to decrease before 15 h in only one test combination, which was use of a 5.0% inoculum of S. cremoris and 30°C incubation. In most instances, growth of the pathogen appeared to be completely inhibited when the pH dropped below 4.75.

Inhibition of Enteropathogenic Escherichia coli by Homofermentative Lactic Acid Bacteria in Skimmilk

1977 ◽  
Vol 40 (11) ◽  
pp. 754-759 ◽  
Author(s):  
J. F. FRANK ◽  
E. H. MARTH
Keyword(s):  
Escherichia Coli ◽  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Starter Culture ◽  
Enteropathogenic Escherichia Coli ◽  
Plate Method ◽  
E Coli ◽  
Streptococcus Lactis ◽  
Streptococcus Cremoris ◽  
Plating Method

Inhibition of enteropathogenic Escherichia coli in skimmilk at 21 and 32 C by 0.25 and 2.0% of added Streptococcus lactis, Streptococcus cremoris, or a mixed strain starter culture was studied. After 15 h of fermentation, fermented milks were refrigerated at 7 C and then were tested periodically for survival of E. coli. Three methods for enumeration of E. coli during these fermentations were compared. They included trypticase soy agar (TSA) pour plates, violet red bile agar (VRB) pour plates, and TSA surface plating with a VRB overlay. Lactic cultures had similar inhibitory properties at 32 C, but there were differences at 21 C, with S. lactis being least inhibitory and the mixed strain culture most inhibitory. The VRB pour plate method gave poorest recovery of E. coli when fermentation was at 32 C and when fermented milks were refrigerated. The TSA surface plating method apparently allowed for recovery of injured E. coli cells and gave results similar to the TSA pour plate method.

scholarly journals Identifying the Diversity of Dominant LABs from Fermented Dairy Products Dahi and Yoghurt in Eastern Region of Nepal

2019 ◽  
Vol 11 ◽  
pp. 60-64
Author(s):  
Sanjay Mahato ◽  
Aakash Kumar Shahani
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Bulgaricus ◽  
Eastern Region ◽  
Isolation And Identification ◽  
Carbohydrate Utilization ◽  
Variable Nature ◽  
Microbiological Techniques ◽  
Fermented Dairy

The aim of this study was to isolate and identify lactic acid bacteria diversity from dahi/ yoghurt. Curd, also known as commercially prepared yoghurt or homemade Dahi, is formed during the slow lactic fermentation of lactose from milk by thermophilic lactic acid bacteria (LAB). Thirty-five samples of yoghurt and curd were collected from the Biratnagar and isolation and identification of bacteria were done by various microbiological techniques like MRS Agar inoculation, colony characteristics, microscopic and biochemical examination. A total of sixty-six strains of lactobacilli were isolated from curd and identification of strains was done by biochemical and carbohydrate utilization test. Lactobacillus bulgaricus, L. casei, L. fermentum, L. acidophilus, and Streptococcus thermophilus were identified from curd. pH of samples was between 3.0 to 4.0 for homemade dahi; while 4.34 to 4.5 for commercially available yoghurt. The mean colony count of lactic acid bacteria was 1.4x107–4.9x107 cfu/g. 37.9% of samples contained Streptococcus thermophilus, 30.3% had Lactobacillus bulgaricus. Forty-five isolates from 24 industrial yoghurt samples showed 37.5% of the yoghurt contained both Lactobacillus bulgaricus and Streptococcus thermophilus followed by 25% samples having S. thermophilus and L. acidophilus. Other species like L. fermentum and L. casei were less common. From 11 homemade dahi samples, 54.5% of curd possessed both S. thermophilus and L. bulgaricus; 18.2% curd had both S. thermophilus and L. fermentum. The study concludes that L. bulgaricus and Streptococcus thermophilus are prevalent potent lactic acid bacteria. This study provides an account of the diversity of lactic acid bacteria in dahi/ yoghurt which will provide useful information about the variable nature of curd in this region to future researchers.

Utilization of Lesser Yam (Dioscorea esculenta L.) Flour as Prebiotic in Yogurt to Total Lactic Acid Bacteria (LAB), Sugar Reduction, and Organoleptic Properties

2020 ◽  
Vol 2 ◽  
pp. 00011
Author(s):  
Yoyok Budi Pramono ◽  
Nurwantoro Bambang Dwiloka ◽  
Sri Mulyani ◽  
Bhakti Etza Setiani ◽  
Maulida Rochmayani ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Raw Materials ◽  
Sugar Content ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Bulgaricus ◽  
Crude Fiber ◽  
Organoleptic Properties ◽  
Randomized Design ◽  
Sugar Reduction

This study aims to determine the effect of the concentration the addition of lesser yam as prebiotic to total Lactic Acid Bacteria (LAB), reducing sugar content, crude fiber, viscosity, and organoleptic properties of yogurt with a combination of three bacteria (Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactobacillus acidophilus). The design of this study used a completely randomized design (CRD) with 4 treatments and 5 replications with variations in the addition of lesser yam tuber, namely T1 with a concentration of 0%, T2 with a concentration of 2%, T3 with a concentration of 4% and T4 with a concentration of 6%. The raw materials used are pasteurized fresh cow's milk, lesser yam tuber flour, and yogurt starter. The results showed that the addition of different lesser yam tuber flour had a significant effect (P &lt;0.05) on total LAB, sugar reduction, crude fiber, viscosity, and organoleptic properties of yogurt. The ideal treatment for the addition of lesser yam tuber flour is the concentration of 2% lesser yam tuber, which produces a total LAB is 9.2 x 109, a sugar reduction is 0.653 mg/mL, crude fiber is 1.3%, 82.25 cPs, and organoleptic properties had sour taste and viscosity is rather thick which the most preferred.<br>

Behavior of Listeria monocytogenes in the Presence of Lactic Acid Bacteria in an Agitated Medium with Internal pH Control

1991 ◽  
Vol 54 (3) ◽  
pp. 183-188 ◽  
Author(s):  
JANE M. WENZEL ◽  
ELMER H. MARTH
Keyword(s):  
Lactic Acid ◽  
Statistical Analysis ◽  
Listeria Monocytogenes ◽  
Lactic Acid Bacteria ◽  
Lactococcus Lactis ◽  
Ph Control ◽  
Lactococcus Lactis Subsp ◽  
Streptococcus Lactis ◽  
Streptococcus Cremoris ◽  
Internal Ph

An agitated medium with internal pH control (IPCM-2) was inoculated to contain Listeria monocytogenes (strain V7, Scott A or California) at ca. 103 CFU/ml and Streptococcus cremoris (Lactococcus lactis subsp. cremoris) or Streptococcus lactis (Lactococcus lactis subsp. lactis) at 0.25 or 1.0% The inoculated medium was incubated with shaking in a waterbath at 30°C for 30 h. L. monocytogenes and lactic acid bacteria were enumerated and pH was determined at appropriate intervals. The area on a figure between curves for the control and treatment and designated as the area of inhibition (AI) was calculated and used to quantify inhibition of each strain of L. monocytogenes for a particular set of conditions in IPCM-2. Statistical analysis of AI values calculated from data obtained at 6, 24, and 30 h of incubation revealed no significant (p &lt; 0.05) difference in inhibition among the three strains of L. monocytogenes for each type of lactic streptococcus present. Streptococcus cremoris was significantly (0.01 &lt; p &lt; 0.05) more inhibitory to all three strains of L. monocytogenes than was S. lactis at 24 and 30 h of incubation. IPCM-2 is considered ready for use at a pH of 5.4 or less, which was reached between 12 and 15 h of incubation in samples containing 0.25 or 1.0% S. cremoris. Populations of L. monocytogenes in such samples were ca. 104 to 106 CFU/ml regardless of strain of Listeria or percentage of S. cremoris added as inoculum. In samples initially containing 0.25 or 1.0% S. lactis, pH 5.4 was not reached until after 18–24 h of incubation. At this point all three strains of L. monocytogenes had grown to ca. 105 CFU/ml regardless of percentage of S. lactis added as inoculum. Despite the inhibition seen, substantial numbers of the pathogen were present when the medium was ready for use.

Shrimp Waste Fermentation Using Symbiotic Lactic Acid Bacteria

2011 ◽  
Vol 194-196 ◽  
pp. 2156-2163 ◽  
Author(s):  
Shan Duan ◽  
Ying Xia Zhang ◽  
Ting Ting Lu ◽  
Dui Xi Cao ◽  
Jing Diao Chen
Keyword(s):  
Lactic Acid ◽  
Lactic Acid Bacteria ◽  
Lactobacillus Acidophilus ◽  
Fermentation Process ◽  
Amino Nitrogen ◽  
Titratable Acidity ◽  
Streptococcus Thermophilus ◽  
Lactobacillus Bulgaricus ◽  
Shrimp Waste ◽  
Whole Process

In this research, shrimp waste was fermented with 3 species of symbiotic lactic acid bacteria, namely Streptococcus thermophilus, Lactobacillus acidophilus and Lactobacillus bulgaricus. The ingredient changes occurring in the fermentation process were investigated. Results showed that the production of lactic acid in the fermentation process was remarkably improved, with the pH decreasing rapidly to 4.25 within 8 h, the lowest pH reaching 3.22, and the titratable acidity reaching 25.0 mmol/100ml. The improved acidic environment promoted the removal of calcium and protein, with 91.3% calcium, 97.7% protein and 32.3% carotenoid removed from shrimp waste after 168 h fermentation. The putrefaction was effectively prevented and the TVBN level was low throughout the whole process. Glucose was consumed rapidly in the earlier phase of the fermentation; about 69.4% glucose was consumed in the initial 24 h. The consumption of glucose was in well accordance with the growth of lactic acid bacteria, the removal of calcium and the increasing of titratable acidity. The amino nitrogen content kept increasing within 48 h, thereafter it came to decrease. 88.4% of peptides in the hydrolysate ranged between 1000 ~ 10000 Da, 10.2% smaller than 1000 Da, and 3.44% larger than 10000 Da.

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