Study of growth of mold (Students ’ Presentation)
Objective • To culture bread mould • Compare the growth of mold under different conditions • Compare the growth of bread mold when different mediums (sweet bread /plain bread) are provided.
Introduction • 10 samples and 2 controls are included. • 10 samples: 5 pieces of sweet bread and 5 pieces of plain bread • On the bread pieces, we swapped microbes from different places to see what kinds of fungus will appear on which of the samples. • 2 controls: a control sample for each: sweet and plain bread
Swapped microbes from different places: Treatments of Sample Sweet bread Plain bread None Control Control sample 1 sample 2 Soil Sample 1 Sample 2 Spoiled food Sample 3 Sample 4 Ventilation duct Sample 5 Sample 6 Shoe base Sample 7 Sample 8 Rubbish bin Sample 9 Sample 10
Type of bread used Sweet bread Method of sampling Any moisture added? Water With the zip bag opened a Ventilation quarter Place we collected the sample No Treatment of sample? In shaded area
Control sample 1 Day 7 White mold appeared.
Type of bread used plain bread Method of sampling Any moisture added? Water With the zip bag opened a Ventilation quarter Place we collected the sample No Treatment of sample? In shaded area
Control Sample 2 Day 7 Mold appeared! A blue spot A green spot
Type of bread used Sweet bread Method of sampling scraping Any moisture added? Water With the zip bag opened Ventilation a quarter Place we collected the sample Soil Treatment of sample? In shaded area
Sample 1 Day 7 White mold White mold
White mold A green spot
Type of bread used Plain bread Method of sampling scraping Any moisture added? Water With the zip bag opened a Ventilation quarter Place we collected the sample Soil Treatment of sample? In shaded area
Sample 2 Day 4 Yellow mold
Sample 2 Day 5 Blue mould Black mould
Sample 2 Day 6 A blue spot White mould
Sample 2 Day 7 Front Back A green spot A blue spot
Sample 2 • became dry and hard after the seven-day experiment as water is absorbed by the mold.
Type of bread used Sweet bread Method of sampling scraping Any moisture added? Water With the zip bag opened a Ventilation quarter Place we collected the sample Spoiled food Treatment of sample? In shaded area
Sample 3 Day 2 Yellow mold
Sample 3 Day 3 The yellow mold spread.
Sample 3 Day 6 The yellow mold became deeper in color.
Sample 3 Day 7 New mold appeared! Little orange spots
Type of bread used plain bread Method of sampling scraping Any moisture added? Water With the zip bag opened a Ventilation quarter Place we collected the sample Spoiled food Treatment of sample? In shaded area
Sample 4 Day 6 White mold( small amounts)
Sample 4 Day 7 Blue spots White mold
Type of bread used Sweet bread Method of sampling scraping Any moisture added? Water With the zip bag opened Ventilation a quarter Place we collected ventilation duct the sample Treatment of sample? In shaded area
Sample 5 Day 5 A green spot mold appeared
Sample 5 Day 6 The green spot became larger
Sample 5 Day 7 Mold becomes larger.
Type of bread used plain bread Method of sampling scraping Any moisture added? Water With the zip bag opened a Ventilation quarter Place we collected the ventilation duct sample Treatment of sample? In shaded area
Sample 6 Day 6 A blue spot Mold appeared!
Type of bread used Sweet bread Method of sampling scraping Any moisture added? Water With the zip bag opened Ventilation a quarter Place we collected the sample Shoe base Treatment of sample? In shaded area
Sample 7 Day 7 White mold( small amounts)
Type of bread used plain bread Method of sampling scraping Any moisture added? Water With the zip bag Ventilation opened a quarter Place we collected the sample Shoe base Treatment of sample? In shaded area
Sample 8 Day 3 Mold appeared! Black spots
Sample 8 Day 6 Black spots Blue spots White mold More mold appeared.
Sample 8 Day 7 Green spots Blue spots
Sample 8 • became dry and hard after the seven-day experiment as water is absorbed by the mold. Teacher may ask other students to discuss whether the above observation is really due to the suggested reason or is due to other reason(s) [Does the above phenomenon happens in other samples as well?]
Type of bread used Sweet bread Method of sampling scraping Any moisture added? Water With the zip bag Ventilation opened a quarter Place we collected the sample rubbish bin Treatment of sample? In shaded area
Sample 9 Day 7 Green mold
Type of bread used plain bread Method of sampling scraping Any moisture added? Water With the zip bag opened a Ventilation quarter Place we collected the sample rubbish bin Treatment of sample? In shaded area
Sample 10 Day 7 Remains unchanged . This sample (sample 10) was collected from a rubbish bin. Sample 9 was also collected from a rubbish bin. Teacher may ask students why there was mold in sample 9 but none in sample 10. Other students are required to judge whether the suggested answer(s) is/are correct.
Results Sweet bread Sample Treatment of No. of Days for No. of Days for Colour of sample mold to odor to fungus appear appear Control sample 1 7 5 White Sample 1 Soil green, white 7 5 Sample 3 Spoiled food 7 4 Yellow, orange Sample 5 Ventilation duct 6 5 green Sample 7 Shoe base 7 5 White Sample 9 Rubbish bin 7 5 Green Teacher may first ask students to comment on data and observation (as many points as they can think of). If necessary, teacher may use the following questions to guide the students to think more deeply about the findings: Can we say the kind of mold in sample 5 grows faster than molds of other samples? Please explain your answer. Why is there odor from the bread? What is the cause? What is the component of the odor?
Plain bread Sample Treatment No. of Days for No. of Days for Colour of of mold to odor to appear fungus sample appear Control sample 2 7 5 green, blue Sample 2 Soil Yellow, Black Blue,green, 4 5 white Sample 4 Spoiled food White, 6 4 Blue Sample 6 Ventilation duct 6 5 blue Sample 8 Shoe base Green, Black Blue, Green 4 5 White Sample 10 Rubbish bin --- 5 --- Teacher may ask students what they can infer from the different colour spots observed in different samples [e.g. students may tell there are different kinds of mold in different places; different types of molds would grow at different rate in different bread (medium); the soil and shoe base contain the greatest varieties of molds, etc. Teacher may ask students their comments on the absence of mold but the detection of odor from sample 10. [What does the odor come from? Activities of bacteria?]
Results • Sample 2 and Sample 8 became dry and hard after the seven day experiment as water is absorbed by the mold. • The white and yellow mold grew through spreading and do not have a regular shape, while mold of other colors (Black, blue, green, yellow, etc.) are spots.
Different Kinds of Fungi in the samples Sample Type of Fungus Control Sample (1-2) Aspergillus oryzae Aspergillus clavatus , Sample 1 & 2 (soil) Acremonium sp. And Cladosporium Sample 3 & 4 (spoiled food) Aspergillus flavus Sample 5 & 6 (ventilation Aspergillus penicilloides duct) Aspergillus clavatus and Sample 7 & 8 (shoe base) Cladosporium Sample 9 & 10 (rubbish bin) Rhizopus
The growth of mold in seven days Sample No. Day1 Day2 Day3 Day4 Day5 Day6 Day7 Control White Sample 1 Control A green spot Sample 2 A blue spot Sample 1 White A green spot Sample 2 Yellow Black White Mold appeared at the back of the sample( a green and a blue spot) Blue A blue spot Sample 3 Yellow Spread of The yellow mold Little orange spots yellow mold became deeper in color Sample 4 White( small White( more) amounts) Blue spots Sample 5 A green The green spot Green spot spot became larger Sample 6 A blue spot Blue spots Sample 7 White( small amounts) Sample 8 Black spots White Yellow Blue spots Green spots Black spots Sample 9 Green (not a spot) Sample 10 No observable change
Sweet bread Plain bread Treatment Colour of fungus Colour of of sample fungus Nil White green, blue Soil Yellow, Black green, white Blue, green, white Spoiled food Yellow, orange White, Blue Ventilation green blue duct Shoe base Green, Black White Blue, green, white Rubbish bin Green ---
Sample Type of Fungus Control Sample (1-2) Aspergillus oryzae Aspergillus clavatus , Sample 1 & 2 (soil) Acremonium sp. And Cladosporium Sample 3 & 4 (spoilt food) aspergillus flavus Sample 5 & 6 (ventilation Aspergillus penicilloides duct) Aspergillus clavatus and Sample 7 & 8 (shoe base) Cladosporium Sample 9 & 10 (rubbish Rhizopus bin)
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