Microbial Evaluation of Ozone Water Combined with Ultrasound Cleaning on Crayfish (Procambarus clarkii)

Abstract

The effects of ozone water (OW) and ultrasound cleaning (UL) on microbial community diversity of crayfish were studied through microbial viable count and 16S rRNA gene sequencing. The results showed that compared with the control (CK), the ozone water combined with ultrasound cleaning (OCU) showed a significant reduction (p < 0.05) in total viable count (TVC), psychrophilic viable count (PVC), mesophilic viable count (MVC), Pseudomonas, hydrogen sulfide-producing bacteria (HSPB), molds and yeasts. Concretely, the TVC of the CK, OW, UL and OCU were 5.09, 4.55, 4.32 and 4.06 log CFU/g, respectively. The dominant bacterium in untreated crayfish was Chryseobacterium, and its relative abundance was reduced by combined treatment. Color measurement and sensory evaluation suggested that a satisfactory sensory experience could be obtained on the crayfish applied with OCU. In brief, OCU could be used as a cleaning strategy to control the microbial quality of crayfish and have no influence on its quality.

The combined effects of ultrasound and plasma-activated water on microbial inactivation and quality attributes of crayfish during refrigerated storage

“…Moreover, a* values of US and UP groups increased more rapidly than that of the control group, implying that US treatment accelerated the increase of redness. Consistent with the current study, Ling et al [26] observed the acceleration effect of US treatments on the increase of redness towards crayfish. It might be attributed to the mechanical effects of US treatment on the crayfish samples, which resulted in cytochrome release.…”

“…For the control group, the initial L*, a* and b* value of crayfish was 42.27, 5.81 and 2.23, respectively. Similar color coordinates of crayfish were reported previously [26] .…”

“…This enhanced antimicrobial effect of UP treatment might result from the cavitation generated by the US treatment, which improved the contact area between PAW and the microorganisms [15] , [41] . Besides, the cavitation was generally accompanied with localized pressure spots and high temperature, which could make the bacterial cytoplasmic membranes fragile and facilitate the penetration of reactive species into bacterial cell walls [26] .…”

“…US has attracted worldwide interest in the food processing field [21] , [22] , [23] , [24] , [25] . Although the antimicrobial effect of individual US treatment is limited [26] , it could significantly benefit the decontamination effect of PAW, especially on the foodstuffs with rough surfaces [19] . On the one hand, the cavitation effect of US could generate a strong jet at the solid–liquid interface, therefore dislodging the microorganisms attached to the food surface [26] , [27] .…”

“…Although the antimicrobial effect of individual US treatment is limited [26] , it could significantly benefit the decontamination effect of PAW, especially on the foodstuffs with rough surfaces [19] . On the one hand, the cavitation effect of US could generate a strong jet at the solid–liquid interface, therefore dislodging the microorganisms attached to the food surface [26] , [27] . On the other hand, the propagation of sound waves generated by US could increase the exposure of hard-to-reach spots to PAW, therefore enabling maximal microbial reductions [28] .…”