Effects of High-Pressure Treatment on Spores of Clostridium Species
Abstract
This work analyzes the high-pressure (HP) germination of spores of the food-borne pathogen Clostridium perfringens (with inner membrane [IM] germinant receptors [GRs]) and the opportunistic pathogen Clostridium difficile (with no IM GRs), which has growing implications as an emerging food safety threat. In contrast to those of spores of Bacillus species, mechanisms of HP germination of clostridial spores have not been well studied. HP treatments trigger Bacillus spore germination through spores' IM GRs at ∼150 MPa or through SpoVA channels for release of spores' dipicolinic acid (DPA) at ≥400 MPa, and DPA-less spores have lower wet heat resistance than dormant spores. We found that C. difficile spores exhibited no germination events upon 150-MPa treatment and were not heat sensitized. In contrast, 150-MPa-treated unactivated C. perfringens spores released DPA and became heat sensitive, although most spores did not complete germination by fully rehydrating the spore core, but this treatment of heat-activated spores led to almost complete germination and greater heat sensitization. Spores of both clostridial organisms released DPA during 550-MPa treatment, but C. difficile spores did not complete germination and remained heat resistant. Heat-activated 550-MPa-HP-treated C. perfringens spores germinated almost completely and became heat sensitive. However, unactivated 550-MPa-treated C. perfringens spores did not germinate completely and were less heat sensitive than spores that completed germination. Since C. difficile and C. perfringens spores use different mechanisms for sensing germinants, our results may allow refinement of HP methods for their inactivation in foods and other applications and may guide the development of commercially sterile low-acid foods.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Sep 01, 2016
- Source ID
- 10.1128/aem.01363-16
Entities
People
- Aimee Shen
- Barbara Setlow
- Christopher J. Doona
- Florence E. Feeherry
- Frank C. Nichols
- Mahfuzur R. Sarker
- Peter Setlow
- Prabhat K. Talukdar
- Wang Shiwei
- William Li
- Yong-qing Li
Organizations
- Army Research Office
- East Carolina University
- National Institute of Dental and Craniofacial Research
- National Institute of General Medical Sciences
- Oregon State University
- University of Connecticut
- University of Vermont