A Bug’s Life: Staphylococcus Aureus

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Staphylococcus is a common bacteria that has many strains which can cause skin infections, food poisoning and even Toxic Shock Syndrome.

February 17, 2022

Staphylococcus, or Staph., is a type of bacteria most often found in the upper respiratory tract as well as on our skin. Most people will have some of these bacteria on their bodies – which allows for the mildly amusing anecdote that staph is found – on the Staff! It is a common skin infection and can be present in abscesses, and sinus infections (like sinusitis). There are different strains of Staph. including Staphylococcus aureus and Staphylococcus epidermidis.

At EMS, we test for Staphylococcus aureus, which can cause food poisoning by developing toxins in food and when ingested causes food poisoning. Symptoms develop within 1-6 hours and last anywhere from 30 minutes to 3 days. Food poisoning caused by Staphylococcus aureus is one of the quicker routes to a sore stomach.

Outbreaks of food poisoning caused by Staphylococcus aureus are rare, especially documented cases, due to the quick onset and recovery of victims. However, any outbreak is usually associated with products that are subject to handling during preparation or dairy products which can become contaminated from the udders of cows and sheep.

How can you prevent spreading Staph.? Wash your hands thoroughly with soap and water, especially before preparing food. If you are ill, avoid preparing food, and cover any open wounds on the hands or wrists with gloves.

The Micro Profile:

Name: Staphylococcus Aureus

Family: Staphylococcaceae

Type of ‘Bug’: Bacteria

Appearance under a microscope: grape-like clusters with round, golden-yellow colonies

History

First discovered in 1880 by Scottish scientist, Alexander Ogston, while performing a procedure. He described the bacteria as looking like “bunches of grapes”. Later, in 1884, Friedrich Julius Rosenbach found that he could differentiate the bacteria by the colour of their colonies: Staph. Aureus was named because of it’s golden colouring.

How do EMS test for Staphylococcus?

The method we use the most to test for Staph, which we are UKAS accredited to carry out is Method No 16 based on BS EN ISO:6888: Part 1: 1999 using Staphytec plus latex confirmation. If you want more information on this method, you can find it here.

EMS Taste and Test – Chilli

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The sensory and nutritional results are in and they might surprise you…

June 2, 2021

Our second Taste & Test was Transport Manager Alan’s Chilli and the sensory results were encouraging!

Here are some highlights:

The Nutritional results were, however, a little surprising and show why nutritional analysis can be so important.

The chilli was prepared with the view that it would be a main meal portion (albeit an indulgent one). We’re all guilty of piling our plates a little high when it comes to our favourite comfort foods, however the nutritional results came back with one mission: to shame us into sharing portions!

In all seriousness, even if this dish was sold as a starter for 2, it would still be very unhealthy. Tasty, comforting and everything you might want after a tough week, but is it worth it?

In the chilli’s defence there are ways to make it healthier, swap out the cheese and nachos for boiled rice, maybe a quarter an avocado instead of half. Also, unsure what % fat that Alan used but you can get less than 5% lean steak mince. This would all help in making a tasty dish a little less likely to kill us all!

The above would all be ways of making this recipe healthier for at home consumption. However, calories may not be as concerning when dining out for a special meal as you would not be eating this indulgently every day.

It is still valuable to customers to be aware of the contents of their food, if someone has high blood pressure, it would be important for them to try to avoid food high in salt. For most people though the odd cheeky high fat/salt meal would not be the worst thing in the world but with the calories on display they can make an informed choice and decide for themselves if this were what they would like to eat. This chilli was worth the calories. 

In the restaurant industry, food portions would have been determined by price of ingredients, staff wages, electricity, rent of property etc. In many eateries, certain dishes can be ordered as a main portion or a starter. This is an option that has been displayed here, with the chilli initially being designed as a main but has been finally presented as a sharing starter for two. Halving the calories per portion but not skimping on taste!

EMS Taste & Test – Buffalo Wings Nutritional Results

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The Nutritional Results for our Buffalo Wings

May 21, 2021

The results are in!

Our very first EMS Taste & Test was a hit – and we’ve already had our second (but more on that to follow shortly)! The sensory test for the Buffalo Wings was a great place to start; it gives the food provider (in this case, the MDs husband, Stuart) a better idea of a flavour profile, appearance feedback and an approximate price that tasters are willing to pay for the dish. All of this information can used to help product placement and provide verified information to customers on flavour and the tasting experience. We currently offer reports of this nature to major retailers such as Lidl, who use our reports to ensure products sold in their stores are as the producer intended and meet all mandatory labelling requirements.

Our Taste & Test would not be complete without a full run-down of the nutritional content. On the front of food products, you buy in a supermarket, you will see a ‘traffic light’ breakdown of nutritional information. This is a legal requirement.

Our Buffalo Wing results are below:

Buffalo wings may not be the healthiest option on the menu and if you are trying to limit your calorie intake or avoid saturated fats or salt, maybe keep them as a special treat! However, they are very high in protein and low in sugar, so if you’re looking to bulk up a bit, hit the gym and want a bite full of protein, these maybe the ideal post work out snack!

Fun fact! Why are Buffalo Wings called buffalo wings when there is no buffalo meat to be found?

It is generally agreed by historians that Buffalo wings were invented by an eating establishment called Anchor Bar in Buffalo NY USA —or rather, their owner Teressa Bellissimo did — the rest of the origin varies but a popular story is after being accidentally shipped wings instead of other chicken parts and, as such, the now famous snack was invented out of a desire not to waste perfectly good poultry. (ref: https://www.tasteofhome.com ; https://en.wikipedia.org/wiki/Buffalo_wing)

If you’re interested in having a go at making these sumptuous buffalo wings at home, click here, put ‘Buffalo Wings’ in the subject line and we will send you the recipe!

First Ever EMS Taste & Test

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We have launched EMS Taste & Test, a place to share your favourite foods and get the the nutritional information back for it. Curious about the nutritional value of your family favourite recipe? Make a batch and send it in!

May 4, 2021

We have launched a new programme of Taste and Test for all those adventurous chefs and retailers out there who want feedback on their favourite dishes! We’re starting small by offering first to our employees and soon after hope to get the local community of cafes, delis and restaurants involved – what happens after that? Well, we hope it will become a new phenomenon where people can access free information on nutritional values, recipes, and recommendations of food in their own locals.

Our first meal was made by our Managing Director’s husband, Stuart, who is a fanatic for American style Buffalo wings. As they are not readily available in the UK he has scoured the internet for the best recipe to make at home. Our MD, Jennifer, gets to enjoy this dish frequently at home and thought sharing this American favourite dish to those who may never of even heard of it was a great launch for wonderful unknown taste sensations to come.

Jennifer, with Stuart’s help, prepared enough buffalo wings for everyone with EMS to have a taster portion as well as a serving for chemistry to test for nutritional content. All the tasters were asked to complete a short survey scoring the dish on appearance and taste. They were also asked to describe the dish to someone who had never eaten it and say what they would be prepared to pay for the meal in a pub.

The sensory results are in are summarised here:

The nutritional report will be ready next week, and we will show you the completed report then. If you are interested in participating in our new venture, please get in touch there is no cost to you but providing the food.

Happy eating!

Why are dilutions important?

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Check out another time lapse video explaining why dilutions are so important.

April 6, 2021

By Michael Beavitt

Accurate dilutions are one of the best used tools in microbiology for determining the number of microbes in something. No matter how many bacteria are in your initial sample, you can always dilute it down to a countable level.

In the timelapse video shown, a high concentration of E.coli was suspended in agar on the top left plate. From left to right, each plate contains a 1 in 10 dilution of that high concentration solution, then a 1 in 10 dilution of that, and so on and so forth.

Footage by Michael Beavitt

Plate one (top left) could be an example of a food sample tested in our lab with a very high bacterial load. After taking 10g of food and homogenising it with diluent, in the case of food tests, one millilitre of this solution would be added to agar, and incubated.

Each blue-green dot you see in the agar is representative of a single bacterium, which has grown into a colony. At a dilution of 1/10, there are far too many bacteria to be counted. They form a confluent lawn of growth across the entire medium. 1/100, and there’s still far too many.

The sample needs to be diluted all the way down to 1/1000000 from the original 10g suspension to allow countable colonies. Then, all it takes is some quick arithmetic to work out how many were in the 10g of food! The bottom right plate, at a dilution of 1/1000000, had 44 colonies. This means that 44000000 bacteria were present in 10g of food.

It’s very rare that anything will have this much E.coli growing on it – it was just used as an example in this case, because it’s easy to grow, and brightly coloured on the agar used. Ordinarily only a 1/10 dilution will suffice for food products! The same principles apply for other enumerations, however – an aerobic colony count will often require 1/1000 or 1/10000 for raw meat and other high risk food types.

If you’re interested, the video was shot for 24 hours, and the E.coli was incubated at 37ºC on TBX agar. Normally they’re incubated at 41.5ºC, but unfortunately my camera is not rated for those kinds of temperatures! The reason that the top 3 plates begin to crack and shrink is because all the lids were left off for ease of filming, allowing the water in the jelly to evaporate. The prolific bacterial growth also sped up the process.

Sampling and Sampling Plan

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A guide to sampling and sampling plans

March 30, 2021

By Michelle Milne

When designing a sampling and analysis plan it is vital that producers identify the information they expect to gain from the plan. For example, to produce a compliant nutritional label that represents the average nutritional data of the whole population of the product on sale. The plan must give an average value to be used on the label taking into account the variability of the product. Robust average nutritional data will help the producer defend a challenge to the label. For example if an independent sample of fish tested by trading standards indicates a 20% variance between the label fat value and the reported result. Evidence of a 25% variance in fat levels over the year would adequately explain the anomaly.

The adequacy and condition of the sample or specimen received for examination are of primary importance. If samples are improperly collected and mishandled or are not representative of the sampled lot, the laboratory results will be meaningless. When submitting a sample for analysis the producer is submitting a small sample of the total population as an estimate of the average of the whole population. In the same way that no two humans have the same fat, protein and moisture ratios the same applies to fish, sheep, pigs or cows etc. A large number of factors can affect the nutritional values of a product. Below is a list of just some factors.

Ingredients:

  • Seasonal Variability
  • Source Variability
  • Supplier Variability
  • Batch Variability
  • Homogeneity

Production:

  • Ingredient Weight Variability
  • Portion Weight Variability
  • Cooking Variability
  • Line Variability
  • Batch Variability
  • Homogeneity
  • Sampling Variability

Testing:

  • Sample Preparation Homogeneity
  • Analytical Uncertainty

Know your product, decide which of the above factors most affect your product and tailor sampling plan to match, compare results from batch to batch or the start, middle and end of a run. From these multiple tests build a picture of the variance in nutritional components such as fat, protein and salt so that all factors influencing the inherent variance of your product are incorporated into a robust nutritional label. Thus providing consumers with the most accurate information about your product.

The New “Cold” War

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A guest blog from Steve Connell, a SARS-COV2 Testing Laboratory Lead about the topic on every news platform: COVID.

March 17, 2021

By Steve Connell

Less than a year ago now, an insidious sneak attack was launched by Nature. Don’t get me wrong, this is not the first of these “unprovoked” attacks on our existence. These attacks are legion in number, this is the nature of Nature, (definitely revisiting that concept!).

What seems like an epoch ago, someone said of SARS-CoV2 (CoVid19), “…it’s just like a bad cold for most folks…..”, to a large extent true, further, some individuals are wholly asymptomatic. However, in the UK this virus has claimed the lives of >120,000 and counting (yep, sometimes one needs to see that as an actual number!)

So, you see, this is a new invader much more pernicious and insidious than we could have imagined. We all fear the infectious disease that claims the lives of most of the people it infects, like the group of diseases generically known as the Viral Haemorrhagic Fever infections, or VHFs, (Ebola is a notable example). However, these, whilst deadly, are not that successful in spreading and replicating, primarily because they kill a high proportion of those they infect. They are successful in their ability to cause human infection, just not so good at ensuring successful spread.

Conversely, SARS-CoV2 (CoVid19), does not kill a high proportion of those it infects, <1% is a small percentage but still a big number in reality. In Scotland, this figure is 4,236 deaths or 0.077% of the total population and 2% of those who have been infected (the known number of positives in the population currently stands at 3.8% in Scotland remember this is known, tested positive cases, NOT the actual number of positives circulating in the community, this is likely to be significantly higher by at least a third). So, it is evident that SARS-CoV2 is a very successful spreader that kills a small percentage but that small percentage turns into a big number when we talk about population(s).

In conflicts of this nature there is a silent escalation in the capability to become successful as a spreader (or from the virus point of view getting genes into the next generation). In the conventional “Cold War” terminology this capability would be centred on advances in technology, implements of combat and amassing forces to utilise these. At critical mass, the combatants enter a war of non-engagement, espionage and a race for, theoretical, supremacy without the heat of engagement.

SARS-CoV2 entered the human arena in 2019 (so far as we know) after spending a not insignificant amount of time amassing mechanisms of insidious attack, on a virgin population (us), in another mammalian incubators, probably bats (not picking on bats unfairly, strains of coronavirus >95% similar to SARS-CoV2 have been isolated from bat colonies). This should not be surprising in the aftermath of other viral infections that have acclimatised in other hosts before going on to infect humans (influenza being a prominent example). This process enables the virus to test multiple versions of itself against immune system challenges, closely related to humans, until it ultimately fails, or in this case, creates a version of itself that can successfully invade mammals and subsequently humans.

We should not anthropomorphosise a virus, as if this process is a directed, targeted intention to infect humans; this process is random, non-directed and scatter gun in the approach. Many, many copies of slightly different virus are produced in live infection, most are unsuccessful. Just as in the Darwinian caveat from Origin of Species, organisms existing under selective pressures will create more offspring than can realistically survive, but some will and these will pass on those inherited characteristics that made them successful, and the cycle goes again. This is why we see variant(s), there are currently >1000 known variants from the originally isolated SARS-CoV2 strain, some are successful Wuhan, Kent, Brazil, South African strains and some have appeared and disappeared. Why are these so highly mutable? Well primarily it is due to the nature of the heritable material that makes up the genome of the virus. Our own information carrying material is DNA, the SARS-CoV2 genome is made from RNA a much less stable information carrying material, prone to non-directed, random mutation, frequently termed as highly mutable.

This mutability is the main weapon developed by the virus in this Cold War, (that, and the human propensity to be social creatures!) only we are now developing our own “molecular weapons” to combat this pernicious, insidious and very successful virus.

In effect, like in a conventional Cold War, we have entered into a molecular level arms race with this foe. The outcome is yet unknown, but next time we can look at the implication(s) of this “Molecular Arms Race”.

One year on: reflecting on our first year in our head office

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After a year of set-backs for some, our Managing Director, Jennifer, celebrates our successes on the first anniversary of our offices and chemistry building.

March 15, 2021

By Jennifer Newton

A year after the pandemic hit the UK, stories are popping up everywhere to mark the anniversary that our normal lives changed. Of course, the pandemic has affected us, but we mark the 15th March 2021 for a positive reason. It is now a year since we moved into our new head offices and custom-built chemistry lab at Unit 5 Mill road Industrial Estate.

In November 2019, it became apparent the unit we were operating out of at 42 Mill Road Industrial Estate was not fit for our growth aspirations. Space was getting tight in the offices as well as the chemistry lab. Will and I were pondering what to do to find more space when serendipity struck and a building which had lay empty for over eight years had a new “for rent” sign up. We acted fast over the Christmas holidays getting in touch with the estate agents and getting access to see inside.

Chemistry lab before

What we found was plenty of usable space, but a lot of work was going to be required to get the building back into tip top shape. The clincher on whether this new building would work, was if we could get a direct line of communication with the micro lab 200 meters away. It just so happened this single-story building had a “folly tower”, basically a two story tower with nothing in it, but a proud place to display a sign. This tower was high enough for us to get the line of site and a seamless communication link which allows both buildings to work in real time with each other.

Chemistry lab after

After frantic negotiations with the owners, we gained entry on the 31st January 2020 and hit the ground running, replacing flooring, carpeting and lights. We laid new drainage and repaired broken ones. We altered the office layout and added two more rooms. We installed new boilers and instated benchwork and tons of electrical points for the chemistry lab. We even had to replace the cat cabling to bring the infrastructure up to current standards.

Our contractors worked tirelessly, as did Will answering the endless questions on where, how and when things needed doing. Then on the 15th March we moved in – no time to spare before the country went into lockdown. Had we delayed even a day, the outcome would have been very different; caught between an unfinished building and an unsuitable one (with no lease). Luck was certainly on our side. If we had not moved when we did, working under the Covid regulations would have been very different with social distancing near impossible to maintain.

Kitchen before
Kitchen after

So, a year on instead of having to decrease our activities we have managed to expand our services with new accredited methods in the chemistry lab, increase the number of technical and customer services personnel and a brand-new Communications Manager to boot. As the offices and the chemistry lab grew so did the micro lab, and we had to rent more warehouse space and a dedicated workshop for our maintenance department. We are now investigating the possibility to move our media production lab to the Unit 5 site (which has loads of surrounding land) to accommodate their continued growth in animal by-product, CSPO (Control of Salmonella Order), food and water testing. Looking back over the year I am proud of what we have accomplished during what can only be described as dark times. As the world returns to normal, I see us attaining even more lofty goals based on the evidence of what we accomplished last year.

Oysters: Dealing with Norovirus

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“If seven in 10 oysters have norovirus, should we still be eating them?”

February 23, 2021

By Jennifer Newton

It’s not often that I get enough time to ponder the specifics of food poisoning from molluscs. But, in the midst of feeling unwell after eating oysters, I found myself doing just that: wondering about the main contributors to food poisoning from oysters (in between trips to the bathroom, that is). A quick google search came up with “Nearly 200 ill in UK after eating oysters”, February 2020. But this is February 2021, so did I also fall ill to the same pathogen?

In the aforementioned article, the culprit was identified as the norovirus. The norovirus symptoms include:

  • Nausea.
  • Vomiting.
  • Stomach pain or cramps.
  • Watery or loose diarrhoea.
  • Feeling ill.
  • Low-grade fever.
  • Muscle pain.

Yep, I had all of them. So, looking pretty likely that I was being affected by the same pathogen that brought 200 people to their knees only a year previous. How did I get there? Well, I ate some raw oysters for Valentine’s day, and just over a 24 hours later I was feeling very poorly, which is the typical incubation period of the sickness (one to two days). And I felt unwell for just over a day, which is also in line with its classic diagnosis of lasting 1 to 3 days. The good news is; according to the CDC, people have temporary immunity from re-infection for up to 2 to 3 years.

Based on electron microscopic (EM) imagery, this three-dimensional (3D) illustration provides a graphical representation of a single norovirus virion, set against a beige background. The different colours represent different regions of the organism’s outer protein shell, or capsid.
Image by CDC

This led me to another line of questioning: I ate the oysters raw, but would I have been safe if I cooked them? Quick steaming oysters will not kill norovirus and other pathogens, according to the U.S. Centers for Disease and Prevention. To be safe, seafood must be cooked to an internal temperature of at least 145 degrees Fahrenheit (63°C). Other common sources of norovirus besides oysters include:

  • contaminated foods
  • shellfish
  • ready-to-eat foods, such as salads, ice, cookies, fruit, and sandwiches, that a worker with a norovirus infection has handled
  • any food that contains particles of the faeces or vomit of a person with norovirus

Norovirus is thought to be the most common cause of acute gastroenteritis (diarrhoea and vomiting illness) around the world. It spreads easily through food and drink and can have a big impact on people’s health. It was originally called the Norwalk virus, after the town of Norwalk, OH, where the first confirmed outbreak happened in 1972.

Can we test for norovirus?

Several methods have been developed to extract and test for total norovirus contamination (infectious and non-infectious virus particles) in foods; however, there are no internationally recognized standard methods to date. Despite improvements in our ability to extract viruses from foods, the analysis of rinses and extracts leaves much to be desired. Additionally, the method used to detect norovirus is based on PCR (Polymerase Chain Reaction) which can be costly and not normally a viable option to producers as a screening test.

“If seven in 10 oysters have norovirus, should we still be eating them?” Of course, there is a risk from eating oysters – they are harvested from the wild, after all. But the oyster itself is not the culprit, rather the water in which it is raised. All the oysters sold in the UK are purified for 42 hours, which largely nullifies any danger. But, to be completely safe, you can always cook oysters – or easier still, just zap them in a microwave, which would kill any residual traces of the virus.

So, should we still be eating oysters? Of course: they are good for you, and tasty, too!

Comparing Fat Testing Methods of Milk and Milk Products

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If you’ve ever wondered what methods we use to test for fats in milk and milk products, this post is for you!

February 16, 2021

By Jennifer Newton

There are so many methods to choose from when testing the fat content of milk and milk products. This might be because historically, many unscrupulous farmers watered down their milk and scooped off cream to increase their volumes, so they could make more money whilst the consumer got short-changed. Nowadays, most commercial transactions of selling milk are based on the fat content (who wants to be paying for water?). So, faster and cheaper testing methods are constantly being developed to determine the actual fat content of milk.


The question remains; “what is the best test method for fat content in milk and milk products?” The answer depends on what information you require for your decision. It can be confusing, but first determine your goal. Are you monitoring your herd’s average production? Are you selling an average season production, negotiating a crucial delivery or exporting to an important market?

If it is one of the latter, you want the test method to be recognised internationally and you want a laboratory with ISO 17025 accreditation to be doing your analysis. Those laboratories will have had their testing audited and their results assessed, and they will be using internationally recognised methods.


Whilst the most common laboratory-based method in use today are the Gerber Method in Europe and the Babcock Method in the US, there is agreement amongst experts that the ultimate precision method for determination of milk fat content is the Röse-Gottlieb (Bogomolov et al., 2017). The Babcock and Gerber method are very similar methodologies, and it has been found that the Gerber method measures consistently but only slightly higher than the Röse-Gottlieb method (Crocker et al., 2009).


If you need an accredited test for fat content in milk, cream or ice cream or would like some more information feel free to contact us.