The data available in literature concerning thermal conductivity and volumetric specific heat values of plant products show substantial discrepancies that arise not only from their varying moisture content or temperature at measurement. Hence, a quick, low cost field and lab method to determine these characteristics of plant material proves to be essential. Application of the line heat pulse method (LHPM) seems to be the optimal solution for the problem. The paper presents the study on the measurement accuracy results related to these properties of selected fruits and vegetables measured by means of a two-needle probe at the range of its positive and negative temperatures of foodstuff. It was found that the LHPM is applicable for quick measurement of thermal conductivity and volumetric specific heat over the positive temperatures. Agreement between the predicted and measured values is statistically significant. In the case of thermal conductivity at the phase transition, the measured values and those calculated differ significantly. Notably, the values of thermal conductivity and volumetric specific heat provided by the line heat pulse method and the values computed at the temperature range below the phase change agree to a great extent.