Investigation of effect of cold plasma on microbial load and physicochemical properties of ready-to-eat sliced chicken sausage

Abstract

Sausage may be contaminated with spoilage microorganisms during the processing after cooking and during the chilling process. Non-thermal decontamination such as cold plasma (CP) can be used to prevent the growth of spoilage microorganisms in sausage after packaging. The objective of this study was to investigate the effects of CP on sliced chicken sausage during 60 days of storage. The sausages were divided into three groups: negative control, ultraviolet (UV)-radiated (positive control for 200 and 400 s), plasma (power of 30 and 70 w for 200 and 400 s). The microbial load, pH, color, peroxide value (PV), and textural parameters of the sausages were compared with those of the negative and positive controls. According to the results, total count decreased significantly (p < 0.05) about 1.87 log CFU/g after 400 s of the CP treatment and at the end of storage at 70 w. CP reduced the lightness (L*) and increased redness (a*) more than the UV rays. The PV more increased by UV rather than by plasma. There were no significant changes in pH value and textural parameters after the CP and UV treatments. Although CP more affected some of the physicochemical properties, compared with UV, CP was shown to efficiently inhibit the rapid growth of microorganisms, resulting in a longer shelf-life.

Appendices

Appendix A

$$\begin{aligned} & {\text{GE}} = {\text{logN}}_{0} {-}{\text{ log N}}_{{\text{t}}} \\ & {\text{GE}}:{\text{ germicidal effect}} \\ & {\text{N}}_{0} :{\text{Number of control sample colonies}} \\ & {\text{N}}_{{\text{t}}} :{\text{Number of colonies in the samples after treatment}} \\ \end{aligned}$$

$$PV = \frac{{{ }\left( {{\text{As }} - {\text{ Ab}}} \right)}}{{55/84{ } \times {\text{M }} \times {\text{ W }} \times { }2{ }}}$$

$$\begin{aligned} & {\text{AS}}:{\text{ Sample absorbance value}} \\ & {\text{AB}}:{\text{ Control absorbance value}} \\ & {\text{M}}:{\text{ Slope of the calibration curve }}\left( {0.0{2}} \right) \\ & {\text{W}}:{\text{ Weight of oil sample }}\left( {{\text{gr}}} \right) \\ \end{aligned}$$

Future and research needs

Optimization of the CP parameters such as gas type, power, and process time to reduce the minimal effects of plasma on sausages and other meat products is needed, in addition to further research about the effect of CP on the structure, especially the textural parameters, of sausage.