Expert outlines top 10 tips for efficient formulation troubleshooting

Wayne Morley, PhD, Head of food innovation, Leatherhead Food Research
Wayne Morley, PhD, Head of food innovation, Leatherhead Food Research
As foods become ever more complex, the need to be able to efficiently troubleshoot problems becomes even more critical. In this guest article, Wayne Morley, PhD, head of food innovation at Leatherhead Food Research, outlines his top 10 tips for efficient trouble-shooting.

“Foods these days are becoming ever more complex with new, highly functional ingredients combining together to make interesting microstructures that themselves breakdown in the mouth to release the exciting flavours and textures that consumers demand.

This complexity however means that things can sometimes go wrong and the cause is not always obvious. Indeed, many problems may not be evident until sometime after the launch.

Most technical people working in the food industry will at some time be involved in trouble-shooting activities. Leatherhead is well placed to assist food companies in these and has done so in most food sectors for many years.

Tip 1 – Keep it simple

My first tip is to keep it simple. Play with the sample - stir it gently and vigorously, dilute it in water, pour it out of the container, shake it about and so on. The water test is particularly valuable for emulsion-based products in which you suspect that there may be stability issues.

An oil-in-water emulsion for example, even a very high oil content one such as mayonnaise, will disperse gradually in water with gently stirring, whilst a broken or inverted emulsion will simply be present as lumps in the water.

And whether the sample thickens or thins during simple stirring can tell you a lot about the state of the structuring components such as the proteins, thickeners and emulsion droplets.

Tip 2 – Microscopy starts with the eye

Microscopy is an extremely valuable tool for investigating all kinds of issues in foods as it allows you see the detailed structural elements and identify the components that are present. At least my microscopy colleagues can do this from the wealth of experience that they have built up looking at hundreds or perhaps thousands of samples. Differentiating fat crystals from salt and sugar, and assessing the distribution of protein, are just some of the simplest interpretations that can be made.

Microscopy however does not start at the highest magnification as you will be only looking at a very small part of the sample. Instead start at the lowest magnification, the eye, and then look in more detail at specific elements of the material with increasing levels of magnification in order to work out what has gone wrong.

Also microscopy can often help narrow down which analytical tests will be helpful (see tip 3).

Tip 3 – Analytical tests

There are probably as many tests available for characterising foods as there are foods themselves. And each test can be carried out in any number of different ways. For example I always say that there are lots of ways of measuring viscosity but they are all wrong! What I mean by this is that viscosity is not a single parameter; it depends on the equipment, measuring conditions including time and temperature, pre-treatment of the sample and so on.

So you will need to select the most appropriate analytical tests, both physical and chemical, and then specify the methods so that they can be repeated and the results compared with those from other samples.

Tip 4 – Compare with ‘good’ product

The first question we always ask a client that requires our help with trouble shooting is can they send us samples of ‘bad’ and ‘good’ product. The ‘good’ product may be from an earlier production, be a kitchen or pilot plant sample, or even be a competitor product that represents an essential quality feature.

The tests described above can then be carried out on both samples and a detailed comparison made in order to begin the process of identifying what went wrong. A sample of perfect product may not come along very often so it may be a good idea to freeze if for future reference if this is appropriate.

I have even seen a forward-looking production manager in a factory keep samples from each production run, with each sample of ‘good’ product representing the control for the next production run.

Tip 5 – Don’t trust the specification

Of course robust specifications should be in place for all products so that the production and quality staff know instantly if the product is suitable for release or not. This assumes of course that the specification contains all of the necessary attributes which is not always the case.

This is not the fault of the product developer however, some attributes such as the pourability of a sauce or the spreadability of a margarine may be impossible to characterise with simple quantitative tests.

Where the specification is used however, care must be taken to analyse the trend in performance of the product. For example there may be a problem if the viscosity at the start of the production run is at the bottom of the specification range, and then increases such that it is at the top at the end of production run. Something is clearly changing and it is important to find out what this is before subsequent production runs result in out of specification stock.

Tip 6 – What’s changed?

If the quality changes to an unacceptable extent after producing a product for a long time, then something must have changed. So as well as getting started on the various trouble-shooting tests described here and elsewhere, it is important to try and find out what has changed. Of course everyone will tell you that nothing has changed so you will need to keep asking and digging deeper until you find something.


The first place to look is the ingredients. I previously described in tip 5 the difficulties that can be encountered in identifying the critical ingredient specification parameters, and it is doubly difficult to identify a change to a parameter that has not been specified! For example it may be that the manufacture of an ingredient has transferred from one factory to another which happened to me in the case of a particular grade of carrageenan. The material from the new factory did not work as well as that from the old factory.

As well as the ingredients, you should look for changes in the manufacturing arrangements for the product in question. For emulsion-based products the homogenisation is a key processing step and high-pressure homogenisers in particular should be replaced with care. The new homogeniser for example may require different pressure and temperature settings to result in the same product quality.

Finally in the ‘what’s changed’ section you should consider the packaging. The packaging is of course the ‘skin’ of the product, protecting it from the outside environment. It therefore follows that any change to the materials or composition, especially for multiple-layered laminated packaging, may result in the quality of the product changing at a different rate. Even changing from a plastic to paper tamper-evident feature may be important.

Tip 7 – Storage abuse

Changes in product quality resulting from abuse during storage and transport may be considered to be an extension of tip 6 as changes here are likely to be important.

The quality of a product changes from the time of manufacture through to consumption, and the best that product developers can hope for is that these changes are controlled and reproducible.

This may not be the case however if the product is subjected to elevated temperatures, temperature cycling, or excessive shear action such as shaking. This even extends to sending samples to Leatherhead for trouble-shooting diagnosis. It is no good sending a chilled product by ambient courier as further uncontrolled changes will occur!

Tip 8 – Consumer mis-use

Consumer complaints may be described as a ‘sledgehammer to crack a nut’ as the unacceptable product quality may have nothing to do with the ingredients, manufacturing, or anything else in the control of the producer.

The storage by the retailer or the consumer may be at fault, and it is also important to consider whether the consumer has read the on-pack instructions or not. This applies to the storage time and temperature, and cooking instructions if appropriate, and all of this information should be easily understood by the consumer.

If you can establish that the consumer has abused the product and therefore is at fault for the poor quality, you can politely explain how to do better next time, although you may still have to provide compensation to avoid bad publicity!

Tip 9 – Malicious contamination

The ‘compensation culture’ that exists these days may encourage consumers to complain about product defects that they know were not caused by the producer, and in some cases the contamination may even be deliberate. Glass contamination is a classic example. All factories will have glass control procedures and those that do not use glass as a packaging material may ban it completely from the manufacturing environment.

Any glass complaint should therefore be investigated to determine the type of glass and the likely source, and compensation should not be paid if it can be demonstrated that the glass is from the consumer’s home.

And it is extremely difficult for insects to get into food packs so for thermally processed foods it is a good idea to determine whether the insect has been ‘cooked’ or not. If not then it is likely again to have come from the consumer’s home.

Tip 10 – Don’t be afraid of a quick fix

The final tip is a plea to not be too precious about your product or packaging, even if they have taken you many years to perfect! If you can identify a quick solution during your trouble-shooting activities, even if it not the root cause of the problem, then my advice is to accept this and implement it without delay.

Many years ago a fault developed with a product that I was responsible for, however the product formulation was due to be changed anyway so it was not necessary to resolve the fault as it was more important to concentrate on getting the new product right. In any case the new product contained less fat, was more preferred by consumers, and resulted in fewer complaints than the old one, so everyone was happy!"

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