Dairy Science and Food Technology

Scientific, information & consultancy services for the food industry

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This website uses several applications that use the programming language  PHP.

PHP has been successfully upgraded to PHP 7.  While every attempt was made to minimise disruption, it is likely that there were periods when the Harvard Referencing application was not available.

Apologies for any disruption during upgrading that finished yesterday at 18.00 hours as planned. Hopefully users will see a significant increase in speed of use.

Most applications that worked using PHP 5 required some rewriting to work using PHP 7.

 

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 .

The document produced by Food Standards Australia /New Zealand indicates that the cheese making process can only give a low risk of food poisoning by E. coli  0157:H7 and other pathogens for extra hard raw milk cheeses and designated Swiss-type raw milk cheeses. For other raw milk cheeses e.g. Cheddar and soft cheeses significant risk of pathogen growth and food poisoning exists.

There is significant demand for raw milk cheeses.

There are some options apart from heat treatment that might reduce the concentration of E. coli in milk e.g. some lactic acid bacteria can inhibit the growth of E.coli 01507:H7, lactic cultures that produce H2O2 can activate the lactoperoxidase system and kill or inhibit the growth of many pathogens. On the animal husbandry side, slurry treatment, feeding regime and use of antibiotics may also have an effect.

Can you produce a HACCP plan, that can be validated, that will enable raw milk cheeses like Feta, Camembert and Cheddar to be produced with low risk of causing food poisioning if consumed by "average" consumers?

 

Congratulations to Gary Andrews, who has been awarded "Food Hero of the Year" at the Grow Make Eat Drink Awards 2016.

Gary Andrews, a Dairy Technologist at CAFRE, was nominated for the award by Paul McClean, the owner of Kearney Blue Cheese, for his contribution towards the development of the artisan cheese sector in Northern Ireland.

 
Food hero of the year
Gary was presented with the award by Frank Mitchell from UTV.

Kearney, Blue, a full fat, mould-ripened hard cheese, was  developed by Paul McClean in the village of Kearney, near Cloughy, Co. Down in Northern Ireland and is a cheese connoisseur’s delight. Gary has worked with Paul McClean and many other entrepreneurs to help make their product concepts commercial successes and is a well-deserved winner.

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 .

Launch of new dairy course

 Dairy processing is a very significant pillar of the Irish economy. In 2013 export values for Irish Dairy products and ingredients exceeded €3 billion making an enormous contribution to the domestic economy. The industry exports 85% of all output produced, making Ireland the 10th largest dairy export nation globally. The strongest performing category areas were butter, cheese, infant formula, milk and cream and whole milk powder and whey powders, while fat-filled milk powders, also accounted for 80% of growth in the prepared foods export category.

UCC-Teagasc logo

Ireland’s dairy industry manufactures produces a wide range of consumer products and dairy ingredients. Consumer dairy products including butter, cheese, and dairy-derived products such as yogurts and dairy-based drinks have now been complemented with dairy ingredients including milk-fate derived ingredients, as well as milk protein, infant formula and other nutritional ingredients to cater to infant formula and sports nutrition markets amongst others. The increased sophistication and complexity of the dairy product portfolio has been underpinned by significant advances in dairy sciences led by UCC and Teagasc in addition to the industry’s clear focus on constantly evolving trends in consumers’ lifestyles and consumption behaviours.

In recognition of the growth and diversification of the Irish dairy industry, UCC, in association with Teagasc, has developed a highly innovative, industry-focused, part-time, blended-learning Postgraduate Certificate in Dairy Technology and Innovation. This qualification is aimed to support the further education and training needs of people at work in the dairy industry.

Drawing on UCC’s 90 years’ experience in dairy science education and Teagasc’ dairy research expertise and in light of industry’s needs, UCC and Teagasc have decided to develop and launch this innovative programme

Module Delivery

The programme is delivered by blended learning, involving a combination of online and in-class

sessions. In-class sessions, to encourage interaction and group formation, will be delivered via block

release, where the participant spends 2 days per week for three weeks with classmates (total 6 days

in each semester). The precise weeks for the block release sessions will be made available in advance of the course commencing.

Semester 1 September-December

FS6201 Milk production and quality (5 credits) (Block-release)

FS6202 Dairy chemistry (5 credits) (On-line module)

FE6502 Trends and dynamics across dairy markets (5 credits) (Block-release)

Semester 2 January-March

FS6203 Dairy processing technology (5 credits) (Block-release)

MB6201 Dairy microbiology (5 credits) (On-line delivery)

FE6501 Business processes across the supply chain (5 credits) (Block-release)

For information on admission requirements, programme content, delivery etc. please contact:

Professor Paul McSweeney,

School of Food and Nutritional Sciences, College of Science, Engineering and Food Science, UCC

Tel. 021 490 2011

Email p.mcsweeney@ucc.ie

Mary McCarthy-Buckley,

Food Industry Training Unit, College of Science, Engineering and Food Science, UCC

Tel. 021 490 3363

Email m.mccarthybuckley@ucc.ie

Website: www.ucc.ie/en/fitu/courses/pgcert

The article on Factors affecting plaque formation by bacteriophages has been updated to reflect research on phages for Yersinia enterocolitica. The update details by work by Carlos G. Leon-Velarde and his colleagues (Leon-Velarde et. al., 2016) on the temperature sensitivity of the OmpF receptor on the cell membrane of Y enterocolitica.

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.

Bacteria from the Deinococcus-Thermus grouping have the ability to produce carotenoid pigments and were suspected of involvement in the pinking phenomenon.

The authors' published some results of Raman Spectroscopy of pink areas from the defective cheeses (Figure 1) showing that the red and pinks areas associated with the defect corresponded to peaks of carotenoid compounds.

 Raman Spectroscopy of pink areas of defective cheeses.

Figure 1. Results of  Raman Spectroscopy of pink areas of defective cheeses. From Quigley et. al. (2016).

The red areas were found to be associated with peaks characteristic of lycopane (perhydro-transformed carotenoid from lycopene) which was absent from non-pink regions from the same cheese. The pink layer was also shown to be associated with a carotenoid salt.

The authors isolated Thermus thermophilus, a Gram-negative, non-pathogenic thermophile, often found in hot water from the cheese.  I am not aware that T thermophilus has been identified in cheese before and is an unusual bacterium in many respects e.g. it has multiple copies of its genome that may help confer its extreme resistance to high temperatures. The concentration of T . thermophilus in cheese was surprisingly low, around 103 CFU/g on Castenholz medium.

Cheese manufactured with milk inoculated with the T. thermophilus isolate gave cheese with the pink defect suggesting that T. thermophilus was the causal agent of the pinking defect.

It will be interesting to see if further studies of this defect using growth media can confirm that T . thermophilus is the sole causal agent of the pink / red colour defect.

Literature cited

Quigley L., O’Sullivan D.J., Daly D., O’Sullivan O., Burdikova Z., Vana R., Beresford T.P., Ross R.P., Fitzgerald G.F., McSweeney P.L.H., Giblin L., Sheehan J.J., Cotter P.D.. (2016). Thermus and the pink discoloration defect in cheese. mSystems 1(3):e00023-16. doi:10.1128/mSystems.00023-16. This article can be downloaded from http://msystems.asm.org/content/msys/1/3/e00023-16.full.pdf at no charge.

I had the opportunity to attend the graduation ceremony at CAFRE's Loughry Campus today. It was a pleasure to see the final year food students graduate with a record number of First Class Honours degrees and 2.1's. I had the privilege of teaching Advanced Food Technology to these students and was aware of how hard many of them worked. Most of the graduates have secured employment or post graduate course places and I wish them well in their future careers.

Most years I supervise several final year honours degree students and this year I was pleased to work with Hannah McCollum.

For a number of years students that I have been working with have investigated projects ranging from encapsulation of raising agents to growth of thermoduric bacteria in pasteurizers. This year Hannah continued work on the evaluation of vegetable proteins as alternatives to milk proteins in ice cream-like products. It is difficult to find vegetable proteins that are suitable for use in ice cream-like products. Even commercial non-dairy "ice cream" intended for vegans and those allergic to milk proteins tends to have a slight "beany" taste.

Hannah McCollum

Hannah who graduated with a 2.1 Honours Degree in Food Technology pictured with author.

Hannah has successfully developed an ice cream like product with non-dairy ingredients that tasted better in consumer taste panels than the non-dairy "ice cream" market leader. This product has good commercial potential and I would encourage Hannah to consider marketing the vegan "ice cream".

Workshop Anouncement

After the lifting of Milk Quotas on 1st April 2015, the Northern Irish dairy industry is going through one of its biggest changes in a generation. The potential intensification of activities both at milk production and milk processing stages of the dairy supply chain demands close consideration, particularly in the areas of adequate water supply and wastewater treatment / disposal facilities. As energy conservation and reducing the carbon footprint are now central to the planning of all new and extended developments it is important that growing intensification demands are explored.

CAFRE in association with the Society of Dairy Technology are holding a one day workshop on water demand and wastewater treatment in the context of expansion in the Dairy Sector. This will include an afternoon site visit to LacPatrick, Ballyrashane’s state of the art Anaerobic Digester and Wastewater Treatment Plant in Coleraine.

Date: 17th February 2016
Location: Food Innovation Centre, Loughry Campus, Cookstown, Co. Tyrone
Cost: £20.00

If you would like further information on this workshop please contact Gary Andrews on gary.andrews@dardni.gov.uk or Tel: 028 8676 8270.

Download the course brochure.

The Food Industry Training Unit at University College Cork (UCC) is taking enrolments for its latest Cheese Science & technology training course. The course will be held over the 3 – 5th February 2016. 

The lead trainers are cheese science and technology experts Professors Tim Guinee (Teagasc) and Paul McSweeney (UCC).

For further information contact:

Dr Angela Sheehan
Food Industry Training Unit,
College of Science, Engineering and Food Science
University College Cork
021 4901423

Email: a.sheehan@ucc.ie

Professor Doug Goff from the University of Guelph, Canada will be the lead trainer on an ice cream course at University College Cork (UCC) on the 16th to 18th February 2016. Professor Goff is a widely respected scientist who is a global expert on both the science and manufacture of ice cream and related products.

Further information on this unique opportunity can be obtained from Mary McCarthy-Buckley or Maura Conway at the Food Industry Training Unit at UCC. Contact details follow:

Telephone: +353 21 4903363 / 4903114

 

I was saddened to learn of the death of Dr Bob Crawford. Bob died on the 7th October, 2015 in Edinburgh.

Bob was my boss and PhD supervisor at Auchincruive. He actively encouraged scholarship and research in dairy science and technology not just in Scotland but globally and his department regularly received visits from academics from Brazil, Syria, Iraq, Iran and Israel as well as Europe and North America. His obituary in the Scotsman gives a sense of the man and his achievements. Bob is survived by his three sons, Keith, Gregor and Duncan.

Naomi Posner-Horie, a gelato entrepreneur, from Bloomington, Indiana, recently visited Northern Ireland to discuss gelato production and distribution. During her study tour Naomi visited the Loughry Campus of The College of Agriculture, Food and Rural Enterprise (CAFRE) with the author. CAFRE's Loughry Campus is located close to Cookstown in Mid Ulster.

Naomi met CAFRE Deputy Director Dr Sam Kennedy, who explained the role of Loughry and its work in education, training and extension services in Northern Ireland.

Naomi Posner-Horie pictured with Sam Kennedy and Michael Mullan
Naomi Posner-Horie pictured with Sam Kennedy and Michael Mullan


Joy Alexander and Dr Rosemary McKee discussed the technical support available to food businesses in Northern Ireland from Loughry's technologists. Rosemary also demonstrated equipment for ice cream and gelato manufacture and discussed some of the challenges facing gelato entrepreneurs in the UK.

Joy Alexander and Rosemary McKee discuss gelato manufacture
Joy Alexander and Rosemary McKee discuss gelato manufacture

 Derek McDowell reviewed the extensive range of full time and part times courses in food offerred and explained the training available for those already employed in the industry. Mary Ireland, Senior Food Packaging Technologist discussed the packaging testing work done in Loughry’s Food Packaging Centre.

Mary Ireland and Derek McDowell discuss the packaging work at Loughry
Mary Ireland and Derek McDowell discuss the packaging work at Loughry

 Speaking to the author after the visit Naomi looked forward to taking students from CAFRE on work experience and sending her staff on courses to CAFRE.

The article on "Goldilocks ice cream", ice cream hardness, has been updated. The article also has a link to download a spreadsheet for plotting the freezing point depression (FTD) curve of an ice cream or gelato mix. The spreadsheet uses a fourth order polynomial regression equation with a R2> 0.9999 to calculate the FPD from the total sucrose equivalent ingredients in the mix.

The summary report on the student projects undertaken by Gemma Devine and George Doran has been added to the DSFT. The report can be accessed at http://www.dairyscience.info/index.php/student-projects.html . Gemma and George were BSc (Hons) Food Technology students at the College Of Food, Agriculture and Rural Enterprise's (CAFRE), Loughry Campus in Cookstown, Northern Ireland.

Growth of thermophilic streptococci in pasteurizers occurs globally and creates major problems for some cheese makers. Excellent media are now available for monitoring the growth of Streptococcus thermophilus and Str. thermophilus-like-organisms in raw and cheese milks making control of problems like off flavours, open texture/blowing and discolouration much easier than previously.

Open texture and blown cheese can be caused by a number of organisms including lactobacilli and leuconstocs.

I had the pleasure of supervising three undergraduate dissertations at CAFRE’s Loughry Campus this year. All three students presented work of a very high standard and I intend to publish summaries of their projects on this website over the next few months.

Gemma Devine and George Doran isolated thermophilic lactic acid bacteria from raw milk and milk ex-pasteurizer at two cheese plants, one in Ireland and the other in Great Britain.  George and Gemma found rapid growth of thermophilic streptococci in the plant in GB. Isolation and identification of the lactic acid bacteria suggested that they could be described with high probability as Streptococcus thermophilus. Sufficient growth of Str. thermophilus was obtained to require significant reduction in the use of starter throughout the production run.

Interestingly Str. thermophilus while found in laboratory-pasteurized raw milk in the Irish plant was not found in the raw milk from the plant in GB. We had expected to find Str. gallolyticus subsp. macedonicus (previously designated as Str. waius and  Str. macedonicus). The Str. thermophilus-like organisms that grow in pasteurizers and often belong to Str. gallolyticus subsp. macedonicus grouping were not identified on this occasion raising the issue of the origin of the Str. thermophilus strains growing in the pasteurizer. Their carbohydrate fermentation pattern, was limited to several sugars and was more typical of starter-derived Str. thermophilus strains than wild strains.

Carbohydrate fermentation profile of strptococcus isolated from pasteurized milkCarbohydrate fermentation profile of a typical thermophilic streptococcus isolated from pasteurized milk from a cheese plant. The streptococcus fermented glucose (11), lactose (29) and sucrose (31) out of the 49 substrates available in the API 50 CHL microbial test kit.

 Kathryn Wilson investigated the manufacture of a vegan ice-cream analogue in which milk fat was replaced with coconut fat and the milk-solids-not-fat replaced with vegetable protein.  Both sucrose and maltitol were evaluated as sweeteners. Kathryn developed a good product that with further work would have commercial potential. Maltitol, a polyol, with a lower glycemic index and energy density than sucrose was found to be an effective substitute for sucrose.

This was a challenging project in that vegetable proteins do not have the neutral taste of milk proteins. Hence suitable flavours to both mask and 'flavour' the frozen dessert were required.

Kathryn, George and Gemma will graduate at Loughry on Friday the 26th June, 2015. I am delighted to congratulate them on their success!

The College of Agriculture, Food and Rural Enterprise (CAFRE) is an integral part of the Department of Agriculture and Rural Development in Northern Ireland. CAFRE's Loughry Campus, located close to Cookstown in Mid Ulster specialises in education, training and extension services in food processing technology. CAFRE has received a number of recent awards from the Chartered Institute of Environmental Health (CIEH) for excellence in training. 

Loughry Food Technology Facility

 The industry training team deliver a wide range of validated, high level courses for industry in the following areas:

Technology
Innovation
Safety and quality
Packaging
Science and nutrition
Business improvement
Energy and waste
Professional development.

 They also design bespoke courses for individual companies and are prepared to deliver at times to meet the needs of customers.

CAFRE has a history of receiving recognition from CIEH for its excellence in training. However, three awards in a row are particularly notable.

Trainee Alison Foster obtained the highest marks in the UK on successful completion of the CIEH Level IV Award in Food Safety Management for Manufacturing. CAFRE staff-member Mrs Claire Millar has received the distinction of receiving the award of the best CIEH-trainer in the UK. And completing the hat trick, CAFRE's Loughry Campus has received the award of the best CIEH centre in the UK.

All three awards will be conferred at a special ceremony at the House of Lords in July, 2015.

 

Rebecca Kirk is publicising an event for UK dairy farmers on 'making more of milk'. The details are given below.

Consistent with the UK Dairy Day 2015 Sharing Knowledge theme, visitors to UK Dairy Day can access a new 'Making More of Milk' zone. This is the first time the UK has provided dairy farmers access to a bespoke area dedicated to making more of milk - an idea of particular relevance in the current economy. If you are interested in receiving more information, please forward your contact details including your email address to info@ukdairyday.co.uk

Date: WEDNESDAY 16th SEPTEMBER 2015

Venue: - TELFORD INTERNATIONAL CENTRE, SHROPSHIRE 

More information:  Contact Rebecca Kirk at info@ukdairyday.co.uk

Predictive microbiology is now an important tool in assessing the safe shelf life of foods. A draft tutorial illustrating how a Ratkowsky or square root model developed by Pan and Schaffner (2010) can be used to predict the growth of salmonella on tomatoes has been added to the DSFT website. The tutorial explains how the equation can be used and illustrates the use of freely available pathogen modelling programmes. A calculator programmed using the model can be used to explore the influence of temperature, initial numbers e.g. 1 CFU/1 kg and time on the growth of salmonella. The calculator was written in ASP and an explanation of how the coding works along with a free, downloadable zip file containing the scripts has been provided. Comments on how to improve the tutorial are welcomed.

 

 

Models and calculators for predicting the shelf life of pasteurized milk and  the mould free shelf life of cakes have been added.

We were delighted to meet Dr Giuseppe Aprea at CAFRE's Loughry Campus recently. Giuseppe Aprea is a researcher at the Istituto G. Caporale in Teramo, Italy. One of his research projects involves the use of phages to control the growth of Listeria monocytogenes in foods. The control of L. monocytogenes is somewhat controversial in that low levels of this pathogen are permitted even in foods in which it would be expected to grow.

 I was pleased to give him my extensive collection of lactococci and their phages and look forward to seeing the results of the genetic studies that he has planned.

Overrun is important in ice cream or gelato manufacture. Apart from contributing to the profitability of an ice cream business, overrun influences important product characteristics. High levels of overrun can be generated using air pumps but there is a maximum value for each ice cream mix and above this value product shrinkage and other problems may develop on storage. The maximum value is dependent on several factors including the MSNF, fat and total solids concentrations of mixes. A calculator has been added to the site to determine the maximum safe level of overrun for an ice cream mix.

Articles on the isolation of lactic acid bacteria from raw and pasteurised milk, suppliers of starter cultures and companies providing exemplary service in the ice cream and frozen desserts sector have been added.

 

Bleaching and decolourisation of cheeses coloured with Annatto is fairly well understood and relatively common. Less common is bleaching in natural cheeses. 

Carotene is the pigment responsible for colour in these cheeses.

The image below shows natural Cheddar cheese (labelled as mature) displaying bleaching around the edges. The cheese was purchased by me from a local supermarket a few days ago. It had a best before date of the 7th March.

Bleaching is normally caused by oxidation of the carotene.

A retail pack problem caused by packaging having a high permeability to oxygen, high intensity florescent light or some other reason? Comments welcome.

Getting phage in environmental samples to form plaques can be challenging. The article "Factors affecting plaque formation by bacteriophages" has been updated. Comments welcome. Please see http://www.dairyscience.info/index.php/enumeration-of-lactococcal-bacteriophages/factors-affecting-plaque-formation.html .

An update on the article on unpackaged bakery items has been given in the Dairy Science and Food Technology Forum. Comments include the risk to the elderly and pregnant women from influenza infection.

Details of the Tref and Z-values for dry heat sterilisation and depyrogenation have been added to the website. The article can be accessed through this link. Using this information site-users can use the thermal processing calculators to determine FH and FD.

There has been a lot of publicity concerning the financial problems of some of the major UK-based food retailers, particularly Tesco and M&S. The larger retailers do have a well deserved  reputation for providing quality food and it was with some surprise when I received photographs showing children handling un-packaged bakery goods from in-store bakeries and then allegedly returning these to the shelves. One report concerned a child with a runny nose!

 

Bakery goods at food retailer

Packaged and non-packaged bakery goods for sale at a major UK food retailer.

I get lots of emails about a range of food-related matters. I can now report on an emerging theme, consumers are starting to complain about the aesthetics of selling unpackaged bakery goods.

Recently I visited several major retailers to look at the situation and yes quite a lot of bakery goods were unpackaged. Apart from tongs and bags to put goods into, there were no obvious  hygiene controls e.g. sneeze guards. So I can understand the aesthetic objections to the nice 'old world' look that some of these bakeries have.

This is not an issue for a particular retailer it concerns several. When I asked the check out operator at one of the stores had anyone ever mentioned that they were unhappy that bakery goods were not packaged she said "Yes. Quite often".  I sometimes wonder if senior management of major UK food retailers, and their partners, actually shop in their stores?

Falafels restaurant in Bloomington, Indiana is a very special place.

It has brought the very distinctive cuisine of Jerusalem, which is based on the culinary traditions of Arab, Jewish and other Mediterranean immigrants, to the US.

Naomi Posner-Horie has now added home-made gelato and sorbet to the menu. Falafels offer over 30 flavours, which are rotated over time. The most popular (and the ones most often on display) are Panna, Cookies n Cream, Pistachio, Caramel Macchiato, Mexican chocolate, and Almond. Popular sorbets are Lemon Lime, and Blueberry.

Naomi Posner-Horie, Gelato entrepreneur.

Naomi Posner-Horie, Gelato entrepreneur.

A section of the gelato on display at Falafels restaurant.

A selection of the gelato on display at Falafels restaurant.

Interestingly customers can also buy vegan (dairy protein and lactose-free) gelato. The new gelato products have been so successful that Naomi is planning to sell pints of gelato, using the brand name “Mami's gelato” at her local Cooperative!

While Naomi had previous experience of making ice cream, gelato was less familiar and she decided to make her own mixes. DSFT is delighted at Naomi’s success and is delighted to have helped in producing balanced ice cream mixes .

Contact details

Address: Falafels Middle Eastern Grill, 430 E Kirkwood Ave. Bloomington, IN 47402

Phone: 812.355.3555

Email: falafels.btown@gmail.com

Web: http://www.falafelsonline.com

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