The spoilage potential and their interactions of Shewanella putrefaciens, Aeromonas hydrophila, and Aeromonas sobria isolated from spoiled Pacific white shrimp (Litopenaeus vannamei) were evaluated by inoculation into sterile shrimp juice during 12 days at 4 °C. Based on the microbiological analysis, A. sobria was identified as non‐spoilage bacteria, and S. putrefaciens and A. hydrophila developed very rapidly as well as with a high maximum cell density in shrimp juice (up to 8.79 log cfu/g and 7.81 log cfu/g after 12 days at 4 °C, respectively). The higher total volatile basic nitrogen and putrescine productions were observed in coculture with S. putrefaciens and A. sobria compared with single culture of A. sobria, suggesting that the growth and spoilage activity of A. sobria were enhanced with S. putrefaciens. Conversely, A. hydrophila was weakly inhibited by S. putrefaciens. It is concluded that the spoilage behavior of microorganisms in mixed culture is significantly different from pure culture. Practical applications We believe that the article may be of particular interest to the readers of this journal as it is the first time investigating the interactions of S. putrefaciens, A. hydrophila, and A. sobria by inoculated in Pacific white shrimp juice. This study could help to reveal the microbial interactions in spoilage food.

A digitally controlled pulse width modulation/pulse skip modulation (PWM/PSM) dual-mode buck DC/DC converter is proposed. Its operation mode can be automatically chosen as continuous conduction mode (CCM) or discontinuous conduction mode (DCM). The converter works in PSM at DCM and in 2 MHz PWM at CCM. Switching loss is reduced at a light load by skipping cycles. Thus high conversion efficiency is realized in a wide load current. The implementations of PWM control blocks, such as the ADC, the digital pulse width modulator (DPWM) and the loop compensator, and PSM control blocks are described in detail. The parameters of the loop compensator can be programmed for different external component values and switching frequencies, which is much more flexible than its analog rivals. The chip is manufactured in 0.13 m CMOS technology and the chip area is 1.21 mm 2 . Experimental results show that the conversion efficiency is high, being 90% at 200 mA and 67% at 20 mA. Meanwhile, the measured load step response shows that the proposed dual-mode converter has good stability.