The author with chemist colleague Ronnie Irvine visited The Echlinville Distillery at Rubane, just outside Kircubbin, in the Ards Peninsula. A brief account of our visit to Ireland's newest whiskey distillery is given here.

 Six new site calculators have been added.

Three are concerned with determining holding tube length, average holding time and Reynolds number:

 Calculator for determining Reynolds number
 Calculator for determining average holding time in a pasteurizer or UHT holding tube
 Calculator for determining holding tube length in pasteurizing and UHT plant

Following feedback from users of data loggers a unique highly flexible F value calculator designed to work with thousands of pasted values of time -temperatures has been added. This calculator allows users, for perhaps the first time, to compare F values obtained by numerical integration using the industry standard method, the trapezoid rule with the more accurate Simpson's 1/3 and 3/8 rules:

 • Calculator for determining the lethality (F, value) of a thermal process using the trapezoid and Simpson's rules. 

A calculator for predicting the concentration of HMF, lactulose and furosine in heated milks (whole, semi-skim and skimmed milk) that also calculates the F0, B* and C* values and the destruction of thiamine has been added.  The calculator has been designed to work with thousands of pasted values of time -temperatures. The values are integrated using the industry standard method, the trapezoid rule, and are compared with the more accurate method of numerical integration, Simpson's 1/3 and 3/8 rules:

 Calculator for predicting the concentration of HMF, lactulose and furosine in heated milks (whole, semi-skim and skimmed milk). It also calculates the F0, B* and C* values and the destruction of thiamine. The values are integrated using the industry standard method, the trapezoid rule, and are compared with a more accurate method of numerical integration, Simpson's 1/3 and 3/8 rules. 

A generic F calculator for UHT and similar high temperature processes has been added. The calculator has been designed to work with thousands of pasted values of time-temperatures. The values are integrated using the industry standard method, the trapezoid rule, and are compared with the more accurate method of numerical integration, Simpson's 1/3 and 3/8 rules

• Calculator for determining the lethality (F, B* values) and chemical changes (C* value) for UHT processes using the trapezoid and Simpson's rules. Applicable to all UHT processes and designed to take thousands of pasted values.

A free article, "Ultra-high-temperature (UHT) processing of milk. Process lethality, chemical effects and use of temperature-time-integrators (TTIs) to predict heat treatment and over-processing" has been added to the Dairy Science and Food Technology website.

Typical pot of UHT milkThis article investigates how to calculate the lethal effects of UHT treatment and the usefulness of TTIs for differentiating sterilised, direct and indirectly processed UHT-treated milk. The importance of accessing accurate temperature time-data and knowing holding tube dimensions, flow rate, average and minimum holding time and the flow characteristics (Reynolds number) are discussed. The reliability of a model developed by Claeys et al. (2003) to predict the effects of UHT-processing on hydroxymethylfurfural, lactulose and furosine concentrations in milk is discussed. Free On Line calculators for calculating holding time, average flow rate, holding tube length in UHT and HTST plants are provided. A free On Line calculator programmed using the thermal constants calculated by Claeys et al. (2003) is provided to calculate hydroxymethylfurfural, lactulose and furosine concentrations following heat treatment in skim, semi fat and full fat milks. This calculator also calculates F0, B*, C* and % destruction of thiamine. Two methods of numerical integration are used to measure the cumulative lethal and chemical effects of UHT treatment, namely the Trapezoid and Simpson's rules.

The article can be viewed at https://www.dairyscience.info/index.php/thermal-processing/325-uht-processing.html .

This website gets a lot of Email and occasionally one connects.

According to the Daily Mail as many as 9.75 million people - 15 per cent of the UK population - are believed to have been hit by flu symptoms this week. Some 120 flu deaths have been recorded in England, 21 are known to have died in Scotland and eight in Northern Ireland.

It was against this background that a reader who works for a major food processing company sent me a picture of unpackaged bakery-items completely exposed to the environment at a food retailers with a global reputation for producing safe food. She was surprised that the retailer was not taking action to prevent contamination of their bakery items with airborne viruses and from customers with virus-contaminated hands.

The article on "Factors affecting plaque formation by bacteriophages" has been updated and can be accessed at 

https://www.dairyscience.info/index.php/enumeration-of-lactococcal-bacteriophages/factors-affecting-plaque-formation.html .

  Plaques of phage D29 produced by Mycobacterium avium spp paratuberculosis assayed using  Mycobacterium smegmatis. Image courtesy of Dr Irene Grant, Queens University  Belfast.

Lactic starter cultures have a well deserved reputation for inhibiting, and or in some instances killing, spoilage and pathogenic bacteria not just in dairy foods but in meat and vegetable products also.

While the importance of undissociated lactic acid as an inhibitor of the growth of pathogens by starters has been known for many decades it is only recently that the effect has been quantified for Listeria monocyotgenes in Gouda cheese.

Fat agglomeration is affected by the process parameters used in gelato and ice cream manufacture, the emulsifer stabiliser system and ingredients. Fat agglomeration has a significant role in dryness of extruded ice cream, slow meltdown, good shape retention and resistance to shrinkage during storage. Too much protein can result in an over stable fat emulsion and insufficient fat agglomeration. 

A calculator to determine the maximum MSNF compatible with normal fat agglomeration has been added and can be accessed here.

 

The latest forum post concerns raw milk and A2 milk. The posts can be viewed at https://www.dairyscience.info/forum/where-to-buy-raw-milk-in-uk_topic454.html .

 

There is a legislative requirement in most developed countries for food companies to have validated-HACCP plans for all products. The current E.coli 01507:H7 outbreak in Scotland has been linked to raw milk cheese and the death of one child has been reported. Note there are few examples of well validated HACCPs even from large companies!

There are a number of published risk assessements for raw milk cheeses. One of the most comprehensive, "Microbiological Risk Assessment of Raw Milk Cheese", has been produced by Food Standards Australia /New Zealand using quantitative models developed by the University of Tasmania. The assesment can be downloaded from https://www.foodstandards.gov.au/code/proposals/documents/P1007%20PPPS%20for%20raw%20milk%201AR%20SD3%20Cheese%20Risk%20Assessment.pdf .

Recent deaths associated with the consumption of lettuce and other salad vegetables have been well publicised in the media. How do you advise parents to respond to the risks associated with eating salads and maintain consumption of healthy foods? And would this advice differ if they had an immunocompromised family member? Perhaps you have a view on my response to a query from a parent?  Please see http://www.dairyscience.info/forum/preparing-salads_topic432.html .

Is Thermus thermophilus the causal agent of pinking in cheese?

“Pinking” the development of a red / pink colour in many cheese-types has been known for many years and has been the attention of significant research interest for decades. Much of this research has been inconclusive although some association with lactobacilli has been suggested.

Recently Quigley et. al. (2016) used shotgun metagenomic sequencing to reveal the presence of bacteria corresponding to three phyla, Firmicutes, Actinobacteria, and Deinococcus-Thermus in 8 ‘continental’ cheeses exhibiting pinking. The phylum Deinococcus-Thermus was absent in control cheese.

I purchased one pot of fat-free-natural yoghurt produced by a major dairy company from the Asda supermarket in Cookstown a few days ago. I opened it this lunchtime today (12th June). It had a use before date of the 24th June 2014 (see below).

 

 

 

I noticed the lumps, clumps of curd on the lid immediately. See below.

 

 

Looking at the inside of the container the top part of the yoghurt was less viscous than the bottom, syneresis was starting and grains/lumps/nodules were clearly visible.

 

The grains / nodules can be clearly seen on the spoon images below.

 

 

 

 

 

It is always interesting to see how companies respond to problems. No one answered the contact phone number given on the carton. I also completed a web form on the company website and attempted to contact their PR company using the information on their website. The contact information was not correct however I managed to get the correct information from their website.  I eventually got a response of sorts from the website form.

 

This is the second time in a month that I have bought a stirred yoghurt with this fault. The first time was from a local company in Northern Ireland and it was a natural yoghurt made with whole milk.

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