Decontamination of chicken skin surfaces inoculated with Listeria innocua, Salmonellaenteritidis and Campylobacter jejuni by contact with a concentrated lactic acid solution

Abstract

1. The aim was to establish how poultry skin could be efficiently decontaminated without changing its organoleptic properties.

2. Chicken skins were surface inoculated with Listeria innocua and treated with different acid solutions (2 and 10% lactic acid for 1 and 30 min). Surviving bacteria were enumerated immediately after treatment and after 7 d storage at 4°C.

3. Reductions of up to 2.6 log were reached immediately after treatment. The treatment effect persisted for 7 d storage, when the reduction exceeded 4.59 log for the strongest treatment.

4. Residual levels of lactic acid were not significantly higher than in untreated controls, except for the strongest treatment. A tasting panel found no significant difference between controls and samples.

5. After the initial results, an apparently optimal treatment (5% lactic acid for 1 min) was applied on chicken skins’ surface inoculated with a mix of Listeria innocua, Salmonella enteritidis and Campylobacter jejuni. Treatment efficacy was assessed immediately after treatment and after 1, 4 and 7 d storage.

6. This treatment seems to be very promising from a food processing standpoint, being fast and allowing decimal reductions of 2.00 log for Listeria innocua and 2.38 log for Salmonella enteritidis after 7 d storage, neither significantly increasing skin lactic acid nor causing any organoleptic modifications to the product. The effect of the treatment is significant after one day storage for Listeria innocua and after 4 d storage for Salmonella enteritidis.

Acknowledgements

This work was supported by the European Social Fund (ESF) and the Reunion Island Regional Authority. Thanks to A.T.T. for the translation of this text.