Selection of microencapsulation method to improve antimicrobial agents production by some lactobacillus species and propionibacterium thoenii in dairy products

The aim of this research is to select the agreeable encapsulation method to improve antimicrobial production from Lactobacillus acidophilus, Lactobacillus reuteri, Lactobacillus rhamnosus and Propionibacterium thoenii. The effect of different organic acid concentrations [1 and 2 w/v], different pH values [3, 4, 5, 6. 7 and 8], different temperature degrees [0, 7, 25, 37 and 45°C] and storage temperature on viability of encapsulated bacteria were investigated. Also, the efficiency of microencapsulated methods [alginate + NaCI, alginate + oil and K-carrageenan] on enhancement of antimicrobial production were studied. Microencapsulation with alginate + NaCI offered greater production in extreme conditions [low pH, low temperature and in the presence of organic acids]. In addition, this method was more effective against pathogenic bacteria by enhancement of antimicrobial production, thus it may be effectively used to increase the safety and the shelf- life of dairy products

Clostridia, enterobacteriaceae, enterococci and its relation to biogenic amines content in Egyptian marketed ras cheese

In this study, 40 samples of Ras cheese were collected and examined for the incidence of Clostridia, Enterobacteriaceae and Enterococci species and detecting their biogenic amines content. 130 isolates were identified and examined for the histamine production. The average count of Clostridia, Enterobacteriaceae and Enterococci were 6 x 102, 7.8 x 102 and 4.4 x 105 CFU/g, respectively. Tyramine, histamine, putrescine, cadaverine, tryptamine and phenylethylamine were detected in 57.5, 100, 42.5, 45, 7.5 and 60% of the examined samples, respectively. Tyramine was observed in most of the cheese samples contaminated with large counts of Streptococcus faecalis [>105 CFU/g]. 25% of the samples contained over 10 mg histamine/100 g cheese. The research discussed the relation between the incidence of Clostridia, Enterococci and Enterobacteriaceae species and the presence of some biogenic amines in Egyptian Ras cheese

Studies of the bacterial flora of raw milk in Fayoum markets

Fifty samples of raw milk were randomly collected from fayoum markets for bacteriological examination. The average counts of enterococci, coliform group, staphylococci, clostridium, aerobic spreformers and Bacillus cereus were, 80 * 10[4], 12 * 10[3], 17 * 10[2], 3.5 * 10,20 * 10[2] and 3.5 * 10 CFU/ ml respectively. All samples were free from salmonella. In addition psychrotrophic, mesophilic and lactic acid bacteria counts were counted in all the samples. On the other hand, 94.5%, 94.4%, 100% and 11.8% of indentified isolates were Streptococcus faecalis, enteropathogenic Escherichia coli, Bacillus cereus and enterotoxigenic Staphylococcus aureus respectively

Enterotoxiguinity and characterization of staphylococci isolated from human sources

A total of 137 strains isolated from human sources obtained from clinical and subclinical cases were examined for their physiological and biochemical characterization in relation to their enterotoxigenicity. Significant correlation between enterotoxin production and coagulase, thermonuclease, protein A, mannitol fermentation and hemolysin formation was observed. On the other hand, nonsignificant correlation with the other examined characterization was observed. About 31% of the studied strains produced enterotoxins A, B, C, D where enterotoxin A was the most prevalent. Few strains [1.5%] produced more than one enterotoxin