Wayne Morley

Top five trouble-shooting tips

No matter how careful the preparation and trials, in product development things can sometimes go wrong when it comes to manufacturing and selling the product. And it might not be obvious that all is not well until some time after the launch. Wayne Morley (left), ex-technical food developer at Unilever where he worked for 22 years on new flavours and formats and now head of Food Innovation at Leatherhead Food Research, outlines five tips for trouble shooting.

Most technical people working in the food industry will at some time be involved in trouble-shooting activities.

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 gentle 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

Tip 4 – Compare with a ‘good’ product. A customer described the tea pictured right as very weak. Under the microscope it is clear to see that there is lots of woody plant material mixed in with the tea leaves compared with a brand-leading tea bag, pictured left.

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.

sample of perfect product may not come along very often so it may be a good idea to freeze it 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, 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.

Morley’s next five tips will be published in the May/June issue of Leatherhead’s FoodCom newsletter, and will be republished here.

Source: Leatherhead Food RA: www.leatherheadfood.com