IGEM:University of Debrecen:Making petri dishes

 Scientific background  

A Petri dish (or Petri plate or cell culture dish) is a  <span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">shallow    <span style="mso-bookmark: OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt; font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black;mso-themecolor:text1">glass   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5">  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">    <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">or   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">plastic  <span style="mso-bookmark: OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5">  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">cylindrical  <span style="mso-bookmark: OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">lidded dish that   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">biologists  <span style="mso-bookmark: OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">use to   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">culture  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5">  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5">  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">cells  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5">  <span style="mso-bookmark: OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt; font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black;mso-themecolor:text1">. It was named after   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">German  <span style="mso-bookmark: OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1"> bacteriologist   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">Julius Richard Petri  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5">  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">,  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">who invented it when working as an assistant to   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">Robert Koch  <span style="mso-bookmark: OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">. Glass Petri dishes can be reused by   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">sterilization  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5">  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">(for example, in an    <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark: OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">autoclave   <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5">  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">    <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;;color:black; mso-themecolor:text1">or by dry heating in a hot air oven at 160°C for one hour). For experiments where cross-contamination from one experiment to the next can become a problem, plastic Petri dishes may have to be disposed of after one use.</o:p>

<p style="margin-top:4.8pt;margin-right:0in;margin-bottom:6.0pt;margin-left: 0in;line-height:18.0pt"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:11.0pt;font-family:&quot;Calibri&quot;,&quot;sans-serif&quot;; color:black;mso-themecolor:text1">Modern Petri dishes often have rings on the lids and bases which allow them to be stacked so that they do not slide off one another. Multiple dishes can also be incorporated into one plastic container to create what is called a "multi-well plate".</o:p>

<p class="MsoNormal"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark: OLE_LINK5"> <span style="font-size:14.0pt;line-height:115%;mso-bidi-font-family: Calibri;color:black;mso-themecolor:text1"><span style="text-decoration: none"> </o:p>

<p class="MsoNormal"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark: OLE_LINK5"> <span style="font-size:14.0pt;line-height:115%;mso-bidi-font-family: Calibri;color:black;mso-themecolor:text1">Material</o:p>

<p class="MsoNormal" style="margin-top:0in;margin-right:0in;margin-bottom:0in; margin-left:15.0pt;margin-bottom:.0001pt;text-indent:-.25in;line-height:normal; mso-list:l0 level1 lfo1;tab-stops:list .5in;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:10.0pt;mso-bidi-font-size:11.0pt;font-family:Symbol; mso-fareast-font-family:Symbol;mso-bidi-font-family:Symbol;color:black; mso-themecolor:text1"> ·<span style="font:7.0pt &quot;Times New Roman&quot;"> <span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1;border:none windowtext 1.0pt; mso-border-alt:none windowtext 0in;padding:0in">Plain gelatin  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1"></o:p>

<p class="MsoNormal" style="margin-top:0in;margin-right:0in;margin-bottom:0in; margin-left:15.0pt;margin-bottom:.0001pt;text-indent:-.25in;line-height:normal; mso-list:l0 level1 lfo1;tab-stops:list .5in;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:10.0pt;mso-bidi-font-size:11.0pt;font-family:Symbol; mso-fareast-font-family:Symbol;mso-bidi-font-family:Symbol;color:black; mso-themecolor:text1"> ·<span style="font:7.0pt &quot;Times New Roman&quot;"> <span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1;border:none windowtext 1.0pt; mso-border-alt:none windowtext 0in;padding:0in">Water  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1"></o:p>

<p class="MsoNormal" style="margin-top:0in;margin-right:0in;margin-bottom:0in; margin-left:15.0pt;margin-bottom:.0001pt;text-indent:-.25in;line-height:normal; mso-list:l0 level1 lfo1;tab-stops:list .5in;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:10.0pt;mso-bidi-font-size:11.0pt;font-family:Symbol; mso-fareast-font-family:Symbol;mso-bidi-font-family:Symbol;color:black; mso-themecolor:text1"> ·<span style="font:7.0pt &quot;Times New Roman&quot;"> <span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1;border:none windowtext 1.0pt; mso-border-alt:none windowtext 0in;padding:0in">Sugar  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1"></o:p>

<p class="MsoNormal" style="margin-top:0in;margin-right:0in;margin-bottom:0in; margin-left:15.0pt;margin-bottom:.0001pt;text-indent:-.25in;line-height:normal; mso-list:l0 level1 lfo1;tab-stops:list .5in;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:10.0pt;mso-bidi-font-size:11.0pt;font-family:Symbol; mso-fareast-font-family:Symbol;mso-bidi-font-family:Symbol;color:black; mso-themecolor:text1"> ·<span style="font:7.0pt &quot;Times New Roman&quot;"> <span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1;border:none windowtext 1.0pt; mso-border-alt:none windowtext 0in;padding:0in">Beef bouillon granules or cubes  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1"></o:p>

<p class="MsoNormal" style="margin-top:0in;margin-right:0in;margin-bottom:0in; margin-left:15.0pt;margin-bottom:.0001pt;text-indent:-.25in;line-height:normal; mso-list:l0 level1 lfo1;tab-stops:list .5in;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:10.0pt;mso-bidi-font-size:11.0pt;font-family:Symbol; mso-fareast-font-family:Symbol;mso-bidi-font-family:Symbol;color:black; mso-themecolor:text1"> ·<span style="font:7.0pt &quot;Times New Roman&quot;"> <span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1;border:none windowtext 1.0pt; mso-border-alt:none windowtext 0in;padding:0in">Foil muffin or cupcake pan cups  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1"></o:p>

<p class="MsoNormal" style="margin-top:0in;margin-right:0in;margin-bottom:0in; margin-left:15.0pt;margin-bottom:.0001pt;text-indent:-.25in;line-height:normal; mso-list:l0 level1 lfo1;tab-stops:list .5in;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:10.0pt;mso-bidi-font-size:11.0pt;font-family:Symbol; mso-fareast-font-family:Symbol;mso-bidi-font-family:Symbol;color:black; mso-themecolor:text1"> ·<span style="font:7.0pt &quot;Times New Roman&quot;"> <span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1;border:none windowtext 1.0pt; mso-border-alt:none windowtext 0in;padding:0in">Muffin pans  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1"></o:p>

<p class="MsoNormal" style="margin-top:0in;margin-right:0in;margin-bottom:0in; margin-left:15.0pt;margin-bottom:.0001pt;text-indent:-.25in;line-height:normal; mso-list:l0 level1 lfo1;tab-stops:list .5in;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:10.0pt;mso-bidi-font-size:11.0pt;font-family:Symbol; mso-fareast-font-family:Symbol;mso-bidi-font-family:Symbol;color:black; mso-themecolor:text1"> ·<span style="font:7.0pt &quot;Times New Roman&quot;"> <span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1;border:none windowtext 1.0pt; mso-border-alt:none windowtext 0in;padding:0in">Ziploc bags  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1"></o:p>

<p class="MsoNormal" style="margin-top:0in;margin-right:0in;margin-bottom:0in; margin-left:15.0pt;margin-bottom:.0001pt;text-indent:-.25in;line-height:normal; mso-list:l0 level1 lfo1;tab-stops:list .5in;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:10.0pt;mso-bidi-font-size:11.0pt;font-family:Symbol; mso-fareast-font-family:Symbol;mso-bidi-font-family:Symbol;color:black; mso-themecolor:text1"> ·<span style="font:7.0pt &quot;Times New Roman&quot;"> <span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1;border:none windowtext 1.0pt; mso-border-alt:none windowtext 0in;padding:0in">Sauce pan and stove  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1"></o:p>

<p class="MsoNormal" style="margin-top:0in;margin-right:0in;margin-bottom:0in; margin-left:15.0pt;margin-bottom:.0001pt;text-indent:-.25in;line-height:normal; mso-list:l0 level1 lfo1;tab-stops:list .5in;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:10.0pt;mso-bidi-font-size:11.0pt;font-family:Symbol; mso-fareast-font-family:Symbol;mso-bidi-font-family:Symbol;color:black; mso-themecolor:text1"> ·<span style="font:7.0pt &quot;Times New Roman&quot;"> <span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1;border:none windowtext 1.0pt; mso-border-alt:none windowtext 0in;padding:0in">Refrigerator  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1"></o:p>

<p class="MsoNormal" style="margin-top:0in;margin-right:0in;margin-bottom:0in; margin-left:15.0pt;margin-bottom:.0001pt;text-indent:-.25in;line-height:normal; mso-list:l0 level1 lfo1;tab-stops:list .5in;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:10.0pt;mso-bidi-font-size:11.0pt;font-family:Symbol; mso-fareast-font-family:Symbol;mso-bidi-font-family:Symbol;color:black; mso-themecolor:text1"> ·<span style="font:7.0pt &quot;Times New Roman&quot;"> <span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1;border:none windowtext 1.0pt; mso-border-alt:none windowtext 0in;padding:0in">Measuring spoons  <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1"></o:p>

<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1;border:none windowtext 1.0pt; mso-border-alt:none windowtext 0in;padding:0in"> </o:p>

<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1;border:none windowtext 1.0pt; mso-border-alt:none windowtext 0in;padding:0in"> </o:p>

<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"> <span style="font-size:14.0pt;mso-fareast-font-family: &quot;Times New Roman&quot;;mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1; border:none windowtext 1.0pt;mso-border-alt:none windowtext 0in;padding:0in">Procedure<o:p></o:p>

<p class="MsoNormal" style="margin-top:7.5pt;margin-right:0in;margin-bottom:7.5pt; margin-left:0in;line-height:normal;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1">Step1 <o:p></o:p>

<p class="MsoNormal" style="margin-top:7.5pt;margin-right:0in;margin-bottom:7.5pt; margin-left:0in;line-height:normal;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1">Be sure that all utensils that will be used are sterilized. Place the muffin cups in the muffin pans without touching the inside of any of the papers.<o:p></o:p>

<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1">Step <span style="border:none windowtext 1.0pt;mso-border-alt:none windowtext 0in; padding:0in">2 <o:p></o:p>

<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1">Mix 4 packages of gelatin, 4 cups of cold water, 8 tsp.  <a href="http://www.ehow.com/how_5326576_make-homemade-petri-dishes.html" target="_blank"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark: OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family: Calibri;color:black;mso-themecolor:text1;text-decoration:none;text-underline: none">sugar   </a><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1">, 4 tsp. bouillon or 4 cubes in a sauce pan. Slowly bring these ingredients to a boil while continually stirring. Pour the hot mixture into the muffin papers until about half full.<o:p></o:p>

<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1">Step <span style="border:none windowtext 1.0pt;mso-border-alt:none windowtext 0in; padding:0in">3 <o:p></o:p>

<p class="MsoNormal" style="margin-top:7.5pt;margin-right:0in;margin-bottom:7.5pt; margin-left:0in;line-height:normal;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1">Cool until the gelatin mixture is solid. Protect the mixture from any contaminants during the cooling process.<o:p></o:p>

<p class="MsoNormal" style="margin-bottom:0in;margin-bottom:.0001pt;line-height: normal;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;; mso-bidi-font-family:Calibri;color:black;mso-themecolor:text1">Step <span style="border:none windowtext 1.0pt;mso-border-alt:none windowtext 0in; padding:0in">4 <o:p></o:p>

<p class="MsoNormal" style="margin-top:7.5pt;margin-right:0in;margin-bottom:7.5pt; margin-left:0in;line-height:normal;vertical-align:baseline"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><a name="OLE_LINK7"></a><span style="mso-bookmark:OLE_LINK7"><span style="mso-fareast-font-family:&quot;Times New Roman&quot;;mso-bidi-font-family:Calibri; color:black;mso-themecolor:text1">Once cool, place each cup liner into a fresh Ziploc baggie. Continue to be careful not to touch the inside of the muffin papers or the mixture itself. Keep the individually packaged petri dishes in the refrigerator until it is time to use them.<o:p></o:p>

<p class="MsoNormal"><span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark: OLE_LINK5"><span style="mso-bookmark:OLE_LINK6"><span style="mso-bookmark:OLE_LINK7"><span style="font-size:10.0pt;line-height:115%;font-family:&quot;Arial&quot;,&quot;sans-serif&quot;; mso-fareast-font-family:&quot;Times New Roman&quot;;color:black"> <span style="mso-bookmark:OLE_LINK4"><span style="mso-bookmark:OLE_LINK5"><span style="font-size:10.0pt;line-height:115%; font-family:&quot;Arial&quot;,&quot;sans-serif&quot;;mso-fareast-font-family:&quot;Times New Roman&quot;; color:black"><br style="mso-special-character:line-break"> <br style="mso-special-character:line-break"> <span style="mso-bookmark:OLE_LINK5"> <span style="mso-bookmark:OLE_LINK4"> <o:p></o:p>