ศูนย์นวัตกรรมเทคโนโลยีหลังการเก็บเกี่ยว

Bacterial population dynamics and decay on leaves of different ages of ready-to-use broad-leaved endive.

Jacques, M. A.; Morris, C. E.;

International Journal of Food Science & Technology Year: 1995 Vol: 30 Issue: 2 Pages: 221-236 Ref: 37 ref.

1995

บทคัดย่อ

Mesophilic, fluorescent and pectolytic bacteria were quantified on leaves of 5 different age groups (AG) of broad-leaved endives before and after ready-to-use (RTU) processing and daily over their 7 d sell by period in France. At harvest, significant differences in bacterial population sizes expressed as log10 c.f.u./cm2 were observed among leaves of different AG resulting in decreasing contamination from outer (-older) to inner (-younger) leaves of the head. This persisted throughout storage at 6 deg C for RTU-processed leaves separated by age implicating leaf physiology as one of its causes. Leaf age also affected types and frequencies of decay occurring during storage. Although the population sizes of mesophilic, fluorescent and pectolytic bacteria populations were always positively correlated, the sizes of fluorescent and pectolytic could not consistently be predicted from mesophilic ones. It is concluded that fluorescent and pectolytic populations should be quantified independently due to t

heir potential role in decay. Atmospheric changes in the packs resulting from vegetable respiration and microbial activity confirmed the limiting effect of high CO2 and low O2 on the development of spoilage without an effect on bacterial population sizes. The importance of the effect of leaf AG for plant cultivation and industrial production of RTU salads is discussed.