Controlling Botulinum

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Controlling botulinum is a vital element of food safety that can have dire consequences if ignored.

February 24, 2022

What is Botulinum?

Botulinum, or Clostridium Botulinum, is a species of the Clostridium. This bacterium can produce toxins in low-oxygen conditions that are deadly. Low oxygen foods include, vacuum packed, canned, and foods with high oil content.

Unlike many other pathogens, labs do not routinely test for C botulinum for two reasons;

It is so deadly that testing a representative sample of food does not provide enough assurance that the entire batch is free from the pathogen.

Most labs do not have the containment levels required to propagate such a deadly bacterium.

Clostridium – Photo by CDC on Unsplash

How it is controlled

So, if routine micro testing isn’t the answer what is?

There are a few ways you can control C botulinum:

  • freezing the food, which works by inhibiting botulism rather than destroying it. This means that once the food is thawed, the botulinum can begin to take effect again, so short shelf-lives of < 10 days are required post thawing
  • high heat / temperature combinations, e.g. like those used in canning
  • having a short-shelf-life of < 10 days for product stored at temperatures > 3°C
  • maintaining a low moisture content or pH throughout the food

Testing

At Express Micro Science we can test your product to prove that C botulinum cannot grow under chilled conditions, so that longer shelf-lives can be achieved.

  • pH – food must be 5 or less throughout the food or throughout all components of complex foods
  • Aqueous salt – food must have 3.5% or greater of salt in the aqueous phase throughout the food or components of complex food
  • Water activity (aw) – food must have 0.97 aw or less throughout the food and throughout all components of complex foods

If your product meets any of the above requirements you are safe to extend your product’s shelf-life beyond 10 days.

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.

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!

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!