The effect of propionic acid and calcium propionate as mold inhibitors and heating preventors in poultry feed stored under Israeli summer conditions was studied in a commercial-scale study.
Heating processes in untreated feed and in feed treated with calcium propionate .5% (w/v) started after 19 and 26 days of storage, respectively, while in feed treated with propionic acid .3% (w/v) heating started after 53 days. Maximum CO2 levels in untreated feed and in feed treated with propionic acid or calcium propionate were 18%, 12.2%, and 9%, respectively, while fungal population density in feed treated with the propionic acid was lower than in calcium propionate-treated feed and control. Aspergillus was the dominate genus among the microfloral population isolated from the feed during storage, whereas Aspergillus candidus was the most frequent species. No aflatoxin was detected in any of the feeds.
It is concluded that propionic acid is a more effective fungistat than calcium propionate under local summer conditions.