The Effectiveness of Fruit Juices in Preventing Microbial Growth On Plain Bread


  • Chris Cai
  • Nikki Ebrahimi-Siaghi
  • Julie Wu


Food waste has developed into a global issue that plays a significant role, not only for the
economy but for the environment. The considerable amount of edible food lost as waste each
year is mainly due to spoilage thus the aim of our study is to determine whether acidic fruit
juices may be used as preservatives in mould growth prevention of bread. We conducted our
experiment by soaking homemade plain bread slices with 5 different treatments for 17 days. We
placed each piece of bread in a separate seal with a 1 cm x 1cm grid across. During the
experimental period, we determined the microbial growth amount by the number of squares that
had developed mould and recorded results daily. Initial results showed that the number of
squares covered increased overtime for all treatments with pH of 4.3 to 6.3 however, by the 10th
day, the more acidic treatments of pH 2.5-3.3 surpassed others with a significant amount of
microbial growth. Further analysis determined statistically significant results with a p-value less
than 0.05 yet an incomplete rejection of our null hypothesis stating that a more acidic liquid with
a low pH will inhibit mould growth when applied to the bread. These results are not entirely
consistent with previous literature which suggests the fruit juices that we had chosen were not
necessarily the most effective antimicrobial agents thus further experimentation may be done
with other solutions to determine what may be the most effective natural preservative.