Inactivation of Lactobacillus plantarum by Pulsed‐Microwave Irradiation

Abstract

Suspensions of Lactobacillus plantarum cells were subjected to either conventional heating, continuous microwave (CW) or pulsed microwave (PW) irradiation at 50°C for 30 min. Samples exposed to PW showed greater reductions (2 ∼ 4 log) in survival counts than those treated with either conventional heating or CW irradiation. As exposure time increased, PW resulted in a remarkable increase in 260 nm‐absorbing compounds that leaked into the suspending menstruum, as compared to CW or conventional heating, indicating that PW irradiated cells were the most injured. The growth of PW irradiated cells was delayed about 24h and the final acidity of the culture broth was about 60 ∼ 80% that of other cells treated with conventional heating or CW irradiation.

Differential Damage in Bacterial Cells by Microwave Radiation on the Basis of Cell Wall Structure

“…However, another argument has also been proposed to explain microbial inactivation by microwaves. Several researchers have attempted to ascertain if such radiation has a nonthermal effect on microorganisms (7,10,27,34). The destruction of microorganisms by microwave at temperatures lower than the thermal destruction point has been observed (11,13,22,24,27).…”

Mathematical models for Enterococcus faecalis recovery after microwave water disinfection

“…This paper showed recovery of L. plantarum after conventional heating, continuous microwave treatment and pulsed microwave treatment (Shin & Pyun 1997). Theoretical models calculated from Equation (10) were used to predict growth curves cited in this paper (Shin & Pyun 1997).…”

“…To examine this model, data from Shin & Pyun (1997) were accurately predicted using our equation. This paper showed recovery of L. plantarum after conventional heating, continuous microwave treatment and pulsed microwave treatment (Shin & Pyun 1997).…”

“…The values of the coefficients C 1 , C 2 and A that gave the best correlation with experimental results for L. plantarum growth are shown in Table 3. In Figure 4 for comparison we plot experimental data from Shin & Pyun (1997) and theoretical curves that were calculated by using Equation (10) with coefficients C 1 , C 2 and A from Table 3. We obtained good agreement between theoretical curves and experimental data.…”

Effect of UV Sterilization on Quality of Centrifuged Takju during Storage

“…탁주를 저온 살균처리에 의하 여 미생물을 사멸시킴으로써 저장기간을 연장하려는 노력 을 계속하고 있으나 가열살균은 약․탁주를 고온에서 장기 간 저장하는 것과 마찬가지의 영향을 주는 것으로 열에 의해 약․탁주 내용물의 산화 및 분해가 촉진되어 화독 냄새 등의 이취가 발생하고 단백질 등의 열변성에 의해 백탁의 생성과 더불어 맛에 영향을 미치며 향기 성분의 손실을 야기한다 (5). 이러한 단점을 지닌 가열 살균을 대체하기 위해 감마선 (3), 막 여과(5), 초고압(high hydrostatic pressure) (6), 마이 크로웨이브(microwave) (7,8), 고전장 펄스 전기장(high voltage pulsed electric) (9), 자외선 살균 (10,11) Operating conditions of sterilizer: UV power, 1,395 W; flow rate, 2.0 L/min; sterilization time, 4 min.…”