Purpose: The objective of this work is to determine the microbiological quality of cold cuts from selected retail outlets in Durban and furthermore look into sodium chloride substitutes that may be used to inhibit Listeria monocytogenes in cold cuts.
Methods: Cold cuts were purchased from four retail outlets in Durban, South Africa and analysed for Aerobic bacteria (AB) , Aerobic sporeformers (ASF), Anaerobic sporeformers (AnSF), E. coli and Listeria monocytogenes. To determine the effect of salts and acid on Listeria monocytogenes, chicken cold cuts were prepared with 2% sodium chloride, 2% potassium chloride, 2% calcium chloride and 2% acetic acid respectively. Samples were inoculated with 108 cfu/ml of Listeria monocytogenes ATCC 7644 stored at 4°C and 7°C for 5 days and Listeriacount was carried out every 24 h.
Results:The mean values of AB, ASF and AnSF in the sampled cold cuts were 5.32 log cfu/g, 1.12 log cfu/g and 0.97 log cfu/g respectively; 91.6% of the cold cuts tested were positive for Listeria and 41.6% were positive for E. coli. It was found that 2% Acetic acid had the most effective inhibition whereas 2% Potassium chloride was the least effective against Listeria monocytogenes under both storage temperatures. Acetic acid showed a significant difference (P < 0.05) in the inhibition of L. monocytogeneshowever there was no significant difference between inhibition with the other antimicrobials.
Significance: This work shows that the sampled cold cuts constitute a public health risk however acetic acid may be successfully used to reduce sodium levels and inhibit pathogens in cold cuts.