The article on the "Reliability of microbial sampling in assuring food safety and calculation of prevalence following negative tests" at 

 https://www.dairyscience.info/index.php/food-model/275-sampling.html has three calculators one of which calculates the number of samples required to meet a microbiological specification. This calculator can be accessed at https://www.dairyscience.info/newcalculators/sample-no.asp .

To encourage students to learn about simple coding for the web I am providing the ASP code for the calculator. The code is in two files, one is the form for entering data and the other processes the data. ASP is old technology and .NET and PHP are now more widely used. However, it is really easy to convert the simple ASP code that I have written to PHP or .NET. The code is in a zipped file that can be downloaded using the link below.

Download the sample number calculator ASP files.

 I have also pasted the code below.

1. Data entry form

<%@LANGUAGE="VBSCRIPT" CODEPAGE="1252"%>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">

<html>

<head>

<table width="97%" height="1030" border="0" align="left">
<tr>
<td width="1005" height="740" colspan="2" valign="top">

</p>
<p align="left"><font size="3" face="Verdana, Arial, Helvetica, sans-serif"> <br />
</font></p>
<form id="form1" name="form1" method="post" action="sample-no1.asp">
<p>&nbsp;</p>
<table width="92%" border="1">
<tr>
<th colspan="2" scope="col"> <h1 class="style1">Calculate the number of samples required to assure the absence of a pathogen or fault-causing organism at a selected probability
</h1>
</h1>
<p class="style2">To use add your values (numerical only) to the empty fields below. </p>
<p>&nbsp;</p></th>
</tr>
<tr>
<td width="520"><font size="3" face="Verdana, Arial, Helvetica, sans-serif">Probability </font></td>
<td width="440"><label for="prob"></label>
<input name="prob" type="text" id="prob" size="10" />
Value is normally 0.95 (95%)</td>
</tr>
<tr>
<td><p><font size="3" face="Verdana, Arial, Helvetica, sans-serif">What mass (g) or volume (mL) of food should be free of the organism?</font></p></td>
<td><label for="volume"></label>
<input name="volume" type="text" id="volume" size="18" />
e.g. 500 g</td>
</tr>
<tr>
<td><font size="3" face="Verdana, Arial, Helvetica, sans-serif">Mass or volume of samples used</font></td>
<td><input name="mass" type="text" id="mass" size="18" />
e.g. 25 g</td>
</tr>
<tr>
<td colspan="2"><div align="center">
<input name="calculate" type="hidden" id="calculate" value="1" />
<input type="submit" name="Submit" id="Submit" value="Calculate the number of samples" />
</div></td>
</tr>
</table>
<p class="style1">&nbsp;</p>
</form>
<h3 align="left" class="style2">&nbsp;</h3>
<font size="3" face="Verdana, Arial, Helvetica, sans-serif">
<p align="center">

</font></td>
</tr>
</table>

 

</body>
</html>

 

2. Data processing script

<%@LANGUAGE="VBSCRIPT" CODEPAGE="1252"%>


<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">

<%

'Code written by Dr Michael Mullan at www.dairyscience.info

 

'Listing variables
if request.form("calculate")=1 then 'to stop remove submission



Dim prob, volume, mass, units, defects, pd, result, rounded 'variables defined




'Taking information from the form


prob=Request.form("prob")
volume=Request.form("volume")
mass=Request.form("mass")
End iF

'Validation

IF prob > 0.99999 THEN

Response.Write "<b>Probability values higher than 0.99999 are not permitted. Please enter an in-scope value.</b><br>"

Else
IF prob <> "" AND volume <> "" AND mass <> "" THEN

'Calculation of defectives and Pdect

units=Round(volume/mass,1)
defects=Round(1/units*100,2)
pd=Round(defects/100,2)

'Calculation of sample numbers
'In ASP log gives ln (natural log) so to give log10 we need to divide ln values by 2.30258509 to give log10 values
Result=Round((log(1-prob)/2.30258509)/(LOG(1-pd)/2.30258509),3)
'I rounded the calculation to 3 decimals to show the result of the calculation
'Next we need to round to next whole number. ASP does not have the Ceiling function of Excel so we need a work around as below. I have used rounded insted of result so that I can show two different values, the actual calculation value and rounded to next whole number
'Thanks to Dr Raymond Martin for sharing the work around

rounded=(log(1-prob)/2.30258509)/(LOG(1-pd)/2.30258509)

If rounded <> Int(rounded) then
rounded = Int(rounded+1)
end if

 

ELSE
Response.Write "<p> There has been a data-entry error. Please note the error message(s) below and ammend your data entry:</p>"
IF prob <> "" THEN
ELSE
Response.Write "<b>The probability has not been given.</b><br>"
END IF
IF volume <> "" THEN
ELSE
Response.Write "<b> You have not entered the mass or volume of food.</b><br>"
END IF
IF mass <> "" THEN
ELSE
Response.Write "<b> A value for the weight or volume of the samples used has not been entered.</b><br>"
END IF

 

End IF

End IF

%>

<html>
<head>

</head>

<body>
<table width="97%" height="1030" border="0" align="left">
<tr>
<td width="1005" height="740" colspan="2" valign="top">
<p align="left"><script async src="//pagead2.googlesyndication.com/pagead/js/adsbygoogle.js"></script>
<font size="3" face="Verdana, Arial, Helvetica, sans-serif"> <br />
</font></p>
<form id="form1" name="form1" method="post" action="">
<div align="center">
<table width="75%" height="407" border="1">
<tr>
<th colspan="2" scope="col"> <h1 class="style1">Results of the calculation to determine the number of samples required</font></h1>
<p>&nbsp;</p></th>
</tr>
<tr>
<td colspan="2" align="center"> <h2 align="left">1.Calculation of % defects and P<sub>def</sub></h2></td>
</tr>
<tr>
<td width="281">Organism should be absent in </td>
<td width="464"><%=volume%>&nbsp;mL or g</td>
</tr>
<tr>
<td>Mass or volume of samples, g or mL</td>
<td><%=mass%>&nbsp;</td>
</tr>
<tr>
<td>Number of sample units in <% Response.write" "&volume&" mL or g " %>&nbsp;</td>
<td><%=units%>&nbsp;</td>
</tr>
<tr>
<td>% Defects</td>
<td><%=defects%>&nbsp;</td>
</tr>
<tr>
<td>P<sub>def</sub></td>
<td><%=pd%>&nbsp;</td>
</tr>
<tr>
<td colspan="2"><h2>2.Calculation of number of samples</h2></td>
</tr>
<tr>
<td>Probability selected</td>
<td><%=prob%>&nbsp;</td>
</tr>
<tr>
<td>Number of samples required</td>
<td><%=result%>&nbsp;</td>
</tr>
<tr>
<td>Sample number rounded to next whole number</td>
<td><%=rounded%>&nbsp;</td>
</tr>
<tr>
<td colspan="2"><div align="left">
<p> <%
If request.form("calculate")=1 AND prob <> "" AND volume <> "" AND mass <> "" THEN
response.write (" "&rounded&" samples of "&mass&" g or mL are required to detect a homogenously distributed organism in a food at a concentration of "&volume&" CFU/L or Kg at a probability of "&prob&". Because of the high probability of clusters being present it is better to take a greater number of smaller samples.")
End IF
%>

</p>
</div></td>
</tr>
</table>
</div>
<p>&nbsp;</p>
</form>
<h3 align="center" class="style2"><a href="/sample-no.asp">Perform another calculation</a></h3>
<h3 align="left" class="style2"><font color="#000000" size="3" face="Verdana, Arial, Helvetica, sans-serif">
</font></h3>
<font size="3" face="Verdana, Arial, Helvetica, sans-serif">
<p align="center">

</font></td>
</tr>
<tr>
<td height="55" colspan="2" bgcolor="#CCCCCC"><div class="style2">
<div id="mainblock">
<div id="main-body">
<div id="maincol">
<div>
<div>
<div>
<div id="maincontent-block">
<table cellspacing="0" cellpadding="0">
<tbody>
<tr>
<td valign="top" align="middle"></td>
</tr>
<tr>
<td valign="top" align="middle"></td>
</tr>
</tbody>
</table>

<div id="bottom">
<div>
<div>
<div class="style2"><a href="http://www.dairyscience.info/index.php/93-articles/notices/115-copyright-legal.html">Copyright &copy; 2015. Dairy Science and Food Technology. All Rights Reserved. Privacy and cookies</a></div>
</div>
</div>
</div>
</div></td>
</tr>
</table>
</body>
</html>

 

Several articles are being prepared and will be added when ready.

Chlorate. Major challenge for milk powder producers. Milk powders can contain high concentrations. Chlorate residues are particularly harmful to babies and young children. Companies that continue to produce milk powders with high concentrations of chlorate are at risk of going out of business.

TCM. Chloroform is another disinfection byproduct and is soluble in milk fat. Unlike chlorate, TCM levels in milk products are generally too low to be of significant public health concern. However, TCM levels could be used by countries to limit imports and thus have potential to be used as a trade barrier.

Urease and nitrification inhibitors in milk. Nitrous oxide (N2O) is a potent greenhouse gas. Its global warming potential could be over 300 times greater than that of CO2 (over a 100-year time scale). Globally, over half of N2O emissions come from agriculture — hence the interest in using urease and nitrification inhibitors on agricultural land to lessen the global warming effects of agriculture. This article looks at their residues in milk and the potential for these residues to be used as trade barriers and to protect indigenous agriculture from imports.

 

 

Compositional standards for ice cream and dairy ice cream

Ice cream manufacturers are required to meet legislation for the composition of their products. Typically compositional legislation defines minimum concentrations of milk fat, milk protein and total solids, but other criteria depending on jurisdiction may also be included. Labeling legislation also distinguishes between ice cream and dairy ice cream.

Global standards

Goff and Hartel (2013) have  reviewed the minimum standards for the composition of ice cream in the major ice cream producing and consuming countries (Table 1).  They stated that while standards were "tightly" specified in some countries e.g. US, they noted a developing trend that "formerly strict compositional standards are being liberalized to allow more flexibility, as in Europe for example". 

Table 1. Minimum standards* for ice cream among the major ice cream producing and consuming countries outside of the European Union

Country

Milk fat (%)

Milk protein (%)

Total milk solids (%)

Total solids (%)

Food solids per litre (g)

Weight per litre (g)

Australia

10

_a

-

-

168

-

Brazil

3b

2.5

-

-

152

475

Canada

10

-

-

36

180

-

United States

10

 

20

 

192

540

New Zealand

10

-

-

-

168

-

 

 

 

 

 

 

 

 

 



 


*Source: Modified from Goff and Hartel (2013)
Not specified

b  Minimum total fat is 8%, the balance can be comprised of non-dairy fat

The Food Labelling Regulations (1996) revoked in the UK in favour of EU legislation (Food Information Regulation, (EU) No 1169/2011)

Since the review by Goff and Hartel (2013), UK regulations for ice cream, which had required that a product labelled as “ice-cream” had to contain a minimum of 5% fat (dairy fat only) and 2.5% milk protein The Food Labelling Regulations (1996) have been revoked by the introduction of EU legislation (Food Information Regulation, (EU) No 1169/2011) to align with EU regulations.

Current  EU-regulations for ice cream, milk ice and dairy ice cream are shown in Table 2.

Table 2.  European industry standards for ice cream, milk ice and dairy ice cream as defined by Regulation (EU) No 1169/2011

 

MSNF

Proteins

Edible fats

 

 

Dairy

Non-Dairy

Dairy

Non-Dairy

Ice Cream

 Not specified

Optional

Optional

Dairy and/or non-dairy edible fats mandatory

Milk Ice

6.0% minimum

Mandatory

Excluded

2.5% min.

Excluded

Dairy Ice Cream

 Not specified

Mandatory

Excluded

5.0% min.

Excluded

 

 

 

 

 

 

 

 

 

 


Source: Adapted from Anon. (2013)

Clearly Regulation (EU) No 1169/2011 has significant implications for ice cream manufacturers and enables the labelling of a product containing no dairy ingredients for the first time as ice cream in the UK. While this may be helpful in producing products for, say, vegans it does have potential for the production of lower quality products.

The Ice Cream Alliance, which represents the industry in the UK, has set out the their recommendations (Pearman, 2015) on a minimum quality standard for ice cream in the UK. They require their members to produce a product containing a minimum of 5% fat and not less than 2.5% milk protein.  This is similar to the previous UK standard except that the origin of the fat is not specified. They have not suggested minimum standards for dairy ice cream.

Oliver Nieburg with Food Navigator has written an interesting article on the concerns of artisan ice cream makers on EU Commission rules to permit up to 5% vegetable fats other than cocoa in "ice cream" and has mentioned French politician Franck Proust's request to the European commission to justify the rule with a written response. Proust's concern is that this rule could threaten the livelihood of artisan ice cream and gelato makers across the EU; larger manufacturers will be able to reduce costs and potentially undermine the smaller, potentially higher quality producers of ice cream and gelato. 

 

Literature / regulations cited.

Anon. (2013). Adapted from "Code For Edible Ices, Version 2013" produced by Euroglaces and available from
http://euroglaces.eu/en/upload/docs/Edible_ices_codes/Code%20for%20Edible%20Ices%20Version%202013.pdf .

Goff, H. D. and Hartel, R. W. (2013). Ice Cream. 7th Edn.  Springer: New York.

Pearman, P. (2015). The Ice Cream Compositional Requirements laid down by the Ice Cream Alliance. Available from: <http://www.ice-cream.org>.

 
How to cite this article

Mullan, W.M.A. (2016). [On-line]. Available from: https://www.dairyscience.info/index.php/cheese-starters/202-uncategorised-sp-269.html . Accessed: 20 October, 2020.  

Welcome to the Dairy Science and Food Technology website.

The content of the site has been transferred to a Content Management System and all the site links have changed. Hence you have been redirected  to this page because you either entered an incorrect URL or because the page URL you entered has been changed.

This is a modified version of the site's index page and hopefully you will be able to use the page links here or the search site function to find the information you need.

The Dairy Science and Food Technology website provides scientific and technological information for students studying food science and technology and may also be of interest to those working in the industry. A discussion forum and interactive content through "On Line" calculators are also provided. A Harvard-type reference wizard and a range of writing/citation resources can also be accessed.

There are sections on starter cultures, probiotics, cheese science and technology, bioactive peptides, ice cream, wine making, modelling in food technology, thermal processing and modified atmosphere packaging and labelling. Some general health information including reference to allergy and food intolerance is also presented.

Thank you for visiting the Dairy Science and Food Technology website.

 

The Dairy Science and Food Technology website provides scientific and technological information for students studying food science and technology and may also be of interest to those working in the industry. A discussion forum and interactive content through "On Line" calculators are also provided.

There are sections on starter cultures, probiotics, cheese science and technology, bioactive peptides, ice cream, wine making, modeling in food technology, thermal processing and modified atmosphere packaging and labelling. Some general health information including reference to allergy and food intolerance is also presented.

PLGYG BROTH

PLGYG is based on the GT medium of Douglas et al (1974) and on MRS broth (de Man, Rogosa and Sharpe, 1960). The composition of PLGYG is given below:

Ingredient

g/Litre

Oxoid Bacteriological Peptone

10.0

Glucose*

10.0

Oxoid Lab Lemco

10.0

Oxoid Yeast Extract

5.0

b-disodium glycerophosphate (Sigma, Grade II)

7.2

pH (after autoclaving) 6.8

 
*Note for best results the glucose and glycerophosphate components should be sterilised separately and added to the sterile basal medium aseptically.


M17 BROTH

M17 broth was developed by Terzaghi and Sandine (1975). The composition of M17 broth is given below:

Ingredient

g/Litre

BBL Peptone

5.0

BBL Phytone Peptone

5.0

Oxoid Lab Lemco

5.0

Oxoid Yeast Extract

5.0

Lactose*

5.0

b-Disodium Glycerophosphate (Sigma, Grade II)

19.0

Ascorbic Acid

0.5

1 ml of 1M MgSO4

0.5

*Note for best results the lactose and glycerophosphate components should be sterilised separately and added to the sterile basal medium aseptically.

Both broth media should be sterilised at 121° C (15 pounds per square inch (psi) ) for 15 min in small portable autoclaves or at 10 psi (110° C) for 15 min in large autoclaves which longer `come up' and 'come down' times. The reduced time in the larger autoclave is necessary since media containing glycerophosphate are moderately heat sensitive.

Ideally the sugar and glycerophosphate component should be sterilised separately and added to the other sterile medium constituents aseptically.

LITERATURE CITED

de Man, J.C., Rogosa, M. and Sharpe, E. (1960). Medium for the cultivation of Lactobacilli. J. Appl. Bacteriol. 23, 103-135.

Douglas, J., Qanber-Agha, a. and Phillips, V. (1974). Medium for the propagation and assay of lactic and other phages. Lab. Practice 23, 3-5.

Mullan, W.M.A., Daly, C. and Fox, P.F. (1981). Effect of cheesemaking temperatures on the interactions of lactic streptococci and their phages. J. Dairy Res. 48, 465-471.

Terzaghi, B.E. and Sandine, W.E. (1975). Improved medium for lactic streptococci and their bacteriophages. Appl. Microbiol. 29, 807-813.

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