Quantification of viable spray-dried potential probiotic lactobacilli using real-time PCR

Abstract

The basic requirement for probiotic bacteria to be able to perform expected positive effects is to be alive. Therefore, appropriate quantification methods are crucial. Bacterial quantification based on nucleic acid detection is increasingly used. Spray-drying (SD) is one of the possibilities to improve the survival of probiotic bacteria against negative environmental effects. The aim of this study was to investigate the survival of spray-dried Lactobacillus plantarum 564 and Lactobacillus paracasei Z-8, and to investigate the impact on some probiotic properties caused by SD of both tested strains. Besides the plate count technique, the aim was to examine the possibility of using propidium monoazide (PMA) in combination with real-time polymerase chain reaction (PCR) for determining spray-dried tested strains. The number of intact cells, Lb. plantarum 564 and Lb. paracasei Z-8, was determined by real-time PCR with PMA, and it was similar to the number of investigated strains obtained by the plate count method. Spray-dried Lb. plantarum 564 and Lb. paracasei Z-8 demonstrated very good probiotic ability. It may be concluded that the PMA real-time PCR determination of the viability of probiotic bacteria could complement the plate count method and SD may be a cost-effective way to produce large quantities of some probiotic cultures. [Projekat Ministarstva nauke Republike Srbije, br. 046010

The Sensory Quality and Volatile Profile of Dark Chocolate Enriched with Encapsulated Probiotic Lactobacillus plantarum Bacteria

“…Obtained results indicate that optimal conditions were achieved during spray drying process. Similar results were obtained in our previous studies [ 23 , 29 ].…”

“…The spray drying encapsulation process was performed according to the method described by Radulović et al [ 23 ]. Overnight cultures (300 mL) were centrifuged (4500× g , 15 min, 15 °C), the pellet was washed twice in 50 mM K 2 HPO 4 (pH 6.5), re-suspended in 300 mL of sterilised reconstituted skim milk (20% w / v ) and spray-dried with a laboratory scale spray-dryer (Büchi mini spray dryer model B-290, Flawil, Switzerland) using the constant inlet air temperature of 170 °C and the outlet temperature of 80 °C.…”

Molecular Methods in Food Safety Microbiology: Interpretation and Implications of Nucleic Acid Detection

“…Viable/dead stains such as ethidium monoazide or propidium monoazide (EMA or PMA) can be applied prior to PCR to exclude free nucleic acids and those present in damaged bacterial cells or viral capsids from PCR detection, since cell membrane integrity is essential for bacterial viability and an intact virus capsid for virus infectivity (Figure , Box 1, and 3). EMA‐ and PMA‐PCR have been widely and successfully applied to detect or quantify viable microorganisms, including bacteria in the vegetative and spore form, yeasts, and fungi (Vesper and others ; Rawsthorne and Phister ; Rawsthorne and others ; Taskin and others ; Elizaquivel and others ; Radulovic and others ; Shi and others ; Zhu and others ; Blooi and others ; Crespo‐Sempere and others ; Dinu and Bach ; Gensberger and others ; Schnetzinger and others ; Singh and others ). However, EMA and PMA can also diffuse into living bacterial cells with intact membranes under certain conditions, albeit at lower efficiency (Nocker and others ).…”

Survival of spray‐dried and free‐cells of potential probiotic Lactobacillus plantarum 564 in soft goat cheese

“…plantarum 564 was performed using the method described by Radulovi c et al (2012). plantarum 564 was performed using the method described by Radulovi c et al (2012).…”