Relating microbial growth to volatiles production in cooked ham in view of the development of a fast method of quality assessment in the cold chain.

Bacterial metabolism in sensitive food products such as cooked ham leads to off-odour and/or off-flavour due to volatiles production. It is obvious that the actual time-temperature profiles a food product undergoes are of paramount importance for ensuring food safety and quality. In this study, spoilage experiments were conducted on modified atmosphere packaged sliced cooked ham stored at different temperatures (2, 8, 12, 15°C) during 7 weeks. For each storage temperature, the evolution of volatiles was monitored over time (at 0, 7 14, 29, and 48 days of storage) using static headspace gas chromatography. The production of ethanol, as a representative volatile deriving from bacterial metabolism, was correlated to lactic acid bacteria, especially Leuconostoc, outgrowth. A threshold value of ethanol concentration was defined in relation with a threshold count numbers of lactic acid bacteria under the conditions studied. Thus, volatiles analysis is proposed as a fast method to assess the bacterial spoilage status of cooked ham during storage and distribution through the cold chain.