Influence of calcium propionate, water activity and storage time on mold incidence and aflatoxins production in broiler starter feed

The effect of calcium propionate at a dose of 5 g/kg on total fungal count and aflatoxins B1 (AFB1), B2 (AFB2), G1 (AFG1) and G2 (AFG2) production in broiler starter feed stored at 0.85, 0.90 and 0.95aw was investigated at 7 days interval for 28 days. All the factors (preservative, aw and storage time) alone and in combination significantly (P<0.001) affected both the total fungal viable counts and aflatoxins production. Minimum total fungal counts (2.60 log10 CFU/g) were observed in calcium propionate added feed at 0.85aw on day 1st of experiment whereas the highest (9.11 log10 CFU/g) in control sample at 0.95aw on 28th day of storage. Regarding aflatoxins, minimum average contents of AFB1 (8.06 ng/g), AFB2 (0.02 ng/g) and AFG2 (0.01 ng/g) were examined in preserved feed on day 1st of experiment at 0.90aw whereas the maximum amounts (173, 3.85, 4.20 ng/g, respectively) were found in control samples at 0.95aw on 28th day of incubation. AFG1 content was lowest (2.05 ng/g) in preserved feed at 0.95aw on the onset of experiment while the highest amount of the toxin (118 ng/g) was noted in control diet at 0.95aw after 28 days of storage. It was concluded that preservative addition along with aw amelioration is a valuable tool for controlling molds incidence and aflatoxins contamination in poultry feed.