Antimicrobial Efficacy of Cinnamaldehyde AgainstEscherichia coliO157:H7 andSalmonella entericain Carrot Juice and Mixed Berry Juice Held at 4°C and 12°C

Abstract

The effectiveness of cinnamaldehyde for inactivating Salmonella enterica and Escherichia coli O157:H7 in carrot juice (CRJ) and mixed berry juice (MBJ) was investigated. Brain heart infusion broth (BHI), CRJ, and MBJ, with concentrations of added cinnamaldehyde ranging from 0.15 to 1.5 μL/mL, 0.25 to 2.0 μL/mL, and 0.25 to 1.5 μL/mL, respectively, were each inoculated with a 5-strain mixture of Salmonella enterica or Escherichia coli O157:H7 to give an initial viable count of 5.07 log colony-forming units/mL. Inoculated BHI or juices without cinnamaldehyde served as controls. Growth of the pathogens in BHI (35°C) was monitored by taking absorbance readings (optical density [OD] 600 nm) for 24 h. The inoculated juices were held at 4°C or 12°C for 24 h, and numbers of viable pathogens were determined at 0, 2, 4, 8, and 24 h by plating samples on selective agar followed by incubation (35°C) and counting bacterial colonies at 48 h. The minimum inhibitory concentration of cinnamaldehyde for both pathogens in BHI was 0.25 μL/mL. The pathogens were more sensitive to cinnamaldehyde in MBJ compared with CRJ, irrespective of storage temperature (p < 0.05). At 4°C, cinnamaldehyde (1.5 μL/mL) completely inactivated S. enterica and E. coli in MBJ (negative by enrichment) within 2 h and 8 h, respectively; whereas both pathogens were detected in CRJ (4°C; with 2.0 μL/mL cinnamaldehyde) at 8 and 24 h. At 12°C, S. enterica and E. coli were undetected in MBJ (1.5 μL/mL cinnamaldehyde) within 2 and 4 h, respectively; however, in CRJ (12°C; 2.0 μL/mL cinnamaldehyde), complete inactivation of S. enterica and E. coli occurred within 4 and 24 h, respectively. Cinnamaldehyde is an effective antimicrobial from natural sources that can be used for inactivating bacterial pathogens in fruit and vegetable juices to enhance microbial safety of these nutritious food products.

Preparation of Fish Skin Gelatin-Based Nanofibers Incorporating Cinnamaldehyde by Solution Blow Spinning

“…The inhibition zone was further increased with increasing cinnamaldehyde from 5% to 30%, indicating that cinnamaldehyde was a concentration-dependent antimicrobial. Similar results were also observed by Manu, et al [ 45 ]. In addition, L. monocytogenes was more sensitive to cinnamaldehyde-loaded nanofibers than E. coli O157:H7 and S. typhimurium at the same cinnamaldehyde ratios.…”

Effects of Elevated Hydrostatic Pressure against Mesophilic Background Microflora and Habituated Salmonella Serovars in Orange Juice

“…Our study similarly shows 2.68, 5.56, and >7.23 log CFU/mL reductions of the pathogen after 2-, 4-, and 8-min treatments at 380 MPa (Sections II, III, and IV of Figure 3 ). Similar reductions, particularly those surpassing the 5-log regulatory requirement for HACCP validation [ 7 ], could be particularly favorable for manufacturers since higher pressure treatments had been associated to higher maintenance cost, lower vessel shelf-life, and higher initial capital investment [ 18 ]. Validated milder treatments with longer time duration could be feasible for small manufacturers who manufacture their products at smaller volumes, and those manufacturers that produce products with additional hurdles such as mild heat, and refrigeration requirement after production.…”

“…Hydrostatic pressure (Barocycler Hub440, Pressure Bioscience Inc., South Easton, MA, USA) of 35 MPa to 380 MPa (15,000 to 55,000 pounds per square inch [PSI]) was applied at 0 (control) to 10 time intervals for decontamination of the inoculated pathogen. This study utilized moderate levels of hydrostatic pressure—higher levels of hydrostatic pressure could lead to higher cost associated with increased maintenance and decreased life of pressure vessels in private industry [ 18 ]. The treatment intensity levels were selected based on preliminary trials (data not shown) at moderate levels of importance to stakeholders of the technology and presented in both English and metric systems.…”

Synergism of Mild Heat and High-Pressure Pasteurization Against Listeria monocytogenes and Natural Microflora in Phosphate-Buffered Saline and Raw Milk

“…This indicates that a treatment at lower pressure and higher temperature (310 MPa at 55 °C), could be comparable ( p ≥ 0.05) to a treatment at higher pressure and lower temperature (380 MPa at 4 °C). This synergism could be of great importance to manufacturing facilities using the technology to lower the cost of operation since lower levels of pressure had been associated with lower maintenance cost and higher shelf-life of the pressure vessels [17]. The cost associated with high-pressure processing is currently the main barrier for further adoption of this technology in the private industry [10].…”