Author(s)

G. K. Omeiza¹, M. Mwanza², S. I. Enem¹, E. Godwin¹, M. A. Adeiza¹, C. Okoli¹

¹Department of Veterinary Public Health and Preventive Medicine, Faculty of Veterinary Medicine, University of Abuja, Abuja, Nigeria.
²Department of Animal Health, Faculty of Natural and Agricultural Sciences, Mafikeng Campus, North West University, Mmabatho, South Africa.

The reducing efficiencies of the commonly used heat treatment methods and fermentation processes on aflatoxin M1 (AFM1) in Nigeria were investigated. Seventy samples of fresh cow milk from both conventional and traditional dairy cattle herds were collected and analyzed for the determination of AFM1 using Cobra-cell incorporated high performance liquid chromatography. Of these analyzed samples, 56 (80.0%) tested positive for AFM1 out of which 3 milk samples with high AFM1 concentrations were selectively pooled and subjected to varied conditions of heat treatments and fermentation processes using both indigenized and exotic strains of lactic acid bacteria (Lactobacillus bulgaricus + Streptococcus thermophilus and L. rhamnosus and L. plantarum) as starter cultures respectively. Both processes used either singly or combined, demonstrated high degrees of reducing effects on AFM1 levels. Sterilization of the milk at 121˚C and 80˚C under the same condition of time (15 - 20) min showed significant reduction of up to 58.8% (p < 0.05) when compared with the fresh untreated cow milk of the same source. Application of heat treatments within the acceptable pasteurization conditions of 61˚C for 15 - 20 min showed no significant reduction (p > 0.05) in the level of AFM1 when compared with the initial mean AFM1 concentration of the untreated fresh milk. The situation was however different around the boiling temperature of 100˚C at which point the level of AFM1 reduction was found to be inconsistent. The indigenized combined strains showed some slight margins of AFM1 reduction in the proportions of (20.5, 30.8 and 43.9)% over and above that of the exotic strains (17.4, 30.0 and 41.1)% in 12 h, 48 h and 72 h of fermentation respectively. Generally, fermentation alone showed lower reduction of AFM1 in milk from 24.5% to 43.9% compared with the reducing activities of (35.4 to 58.8)% when heat-treated milk samples were subsequently subjected to varied fermentation conditions.

Fresh Milk, Aflatoxin M1, Heat Treatment, Fermentation Processes, Nigeria

Omeiza, G. , Mwanza, M. , Enem, S. , Godwin, E. , Adeiza, M. and Okoli, C. (2018) Reducing Efficiencies of the Commonly Used Heat Treatment Methods and Fermentation Processes on Aflatoxin M1 in Naturally Contaminated Fresh Cow Milk. Open Journal of Veterinary Medicine, 8, 134-145. doi: 10.4236/ojvm.2018.88013.