Evidence on the role of protein biosynthesis in the induction of heat tolerance of Lactobacillus rhamnosus GG by pressure pre-treatment

• Published in: International journal of food microbiology 2004-11, Vol.96 (3), p.307-313
• Main Authors: Ananta, E., Knorr, D.
• Format: Article
• Language: English
• Subjects: Bacterial Proteins - biosynthesis; Bacterial Proteins - drug effects; Biological and medical sciences; Cell Membrane; Chloramphenicol - pharmacology; Flow Cytometry; Food industries; Food Microbiology; Fundamental and applied biological sciences. Psychology; heat shock proteins; heat stress; Heat tolerance; heat treatment; High hydrostatic pressure; high pressure treatment; Hot Temperature; Hydrostatic Pressure; induced resistance; lactic acid bacteria; Lactobacillus - metabolism; Lactobacillus rhamnosus; pretreatment; Probiotic bacteria; Probiotics; protein synthesis; protein synthesis inhibitors; Protein Synthesis Inhibitors - pharmacology; temperature; Time Factors; viability
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2004.04.012

It was the aim of this work to evaluate, whether and to which extent heat resistance of Lactobacillus rhamnosus GG is affected by mild pressure treatments prior to exposure to lethal temperatures, such as during spray-drying. It was observed that cells pressure pre-treated at 100 MPa at 37 °C for 10 min showed higher survival than untreated cells when exposed to heat challenge at 60 °C. To gain more insights on the cellular mode of action of pressure induced heat tolerance, flow cytometric analysis was applied in combination with functional dye LIVE/DEAD®BacLight™ bacterial viability kit. Dot plot analysis showed that a lower degree of membrane damage was observed at pressure pre-treated cells upon heat treatment at 60 °C for 3 min. Evaluation of heat inactivation kinetics of cells pressure treated in the presence of chloramphenicol, a protein synthesis inhibitor, pointed out the potential contribution of pressure-induced protein biosynthesis in the enhancement of bacterial heat tolerance.