<![CDATA[S Craig Roberts - Blog]]>Fri, 27 Mar 2026 17:55:04 -0700Weebly<![CDATA[Scrapping milk labels for sniff tests: the whole story stinks]]>Wed, 01 Mar 2017 12:13:30 GMThttps://www.scraigroberts.com/blog/scrapping-milk-labels-for-sniff-tests-the-whole-story-stinksUse-by dates on milk containers are to be scrapped in favour of the classic “sniff test”, according to numerous news outlets this week, under plans being drawn up by the food waste charity WRAP. By the end of the year, so we’re told (e.g. here and here and here), we’ll all be relying on our noses rather than dates, in an effort to save a staggering 500 million pints poured down the sink in Britain each year.
 
An interesting idea? Common sense, even? Perhaps, except that it’s simply not true.
 
The WRAP Report
The charity’s latest report on consumer food waste, published on the 27th February, is a comprehensive 37-page document outlining recent developments in food packaging and labelling. It notes several positive developments, such as supermarkets supplying smaller bags of salad. And it lists recommendations that might help to further reduce waste, such as changing labelling from “use by” to “best before” for certain products, including milk.
 
But there is no mention of sniff tests anywhere in their report, nor in the press release accompanying it, nor is there even the slightest whiff of any such recommendation.
 
Sniffing out Ground Zero
Intrigued, I scented out the source of the story. It turns out that the WRAP report was covered in an excellent article in the Times on the day of its release. The article does highlight the particular case of milk, describing how labels now advise consumption within a much shorter time period than they used to. But there is no mention of sniff tests here either – only the actual WRAP recommendations.

However, the story was accompanied by an amusing commentary – with the tagline “Your nose knows best” - which played with the implications of the recommendations. From there, so it would seem, the story has spread like eau de farmyard on a strong summer breeze, with a bullish base note of Chinese whispers.
 
So there is not, in fact, any such proposal to leave us relying solely on our sense of smell for detecting spoiled milk, or any other kind of food. But would such a test be viable, even if there were?
 
Would a Sniff Test work?
Many of us will have often smelled the milk bottle before using it, and occasionally we will have chosen not to use it because of its smell. Indeed, it is thought that finding and assessing potential food is one of the three main functions of our sense of smell – the other two being related to avoiding infectious matter in the environment and finding partners.
 
The unpleasant aroma of spoiled milk, in particular, arises due to the action of proliferating bacterial populations which occur even in pasteurised milk. The smell itself is actually a cocktail of numerous volatile odour compounds, like acetaldehyde, 3-methyl-1-butanol, and acetic acid. These can smell quite good on their own – acetaldehyde has a fruity smell while methyl butanol is found in the aroma of truffles – but together they form a rather less appetising mixture. Pasteurised milk would likely have to curdle to do you any serious harm – and then you would usually be able to see it quite clearly, let alone smell it – but nonetheless the sniff test could clearly be a useful warning signal.
 
But having to rely on a sniff test alone, for any food product, would be unfortunate. For one thing, our sense of smell varies from day to day and week to week. While known changes in smell sensitivity across a woman’s menstrual cycle might be unlikely to interfere with the detection of spoiled milk, waking up with a stuffy head cold just might.
 
More importantly, a significant proportion of the population suffer from olfactory deficits ranging from mild or moderate impairment to total loss of the sense of smell. Several studies suggest rates of clinical olfactory impairment to be around one in five of the population and particularly high in those of older age, especially men. Often, people are unaware they even have a deficit, possibly because odour is often subconsciously processed in the brain. Furthermore, in up to 4% of the population with congenital anosmia (that is, have no sense of smell since birth), this is often noticed only around the early teenage years.
 
In short, there are vulnerable groups of the population among whom there is both a deficit and a lack of awareness of that deficit, who would be at risk.
 
So scrapping labelling on milk altogether is not what WRAP is recommending, contrary to many headlines. But even if it were, it would not be a great idea. The nose might indeed know best, but only when it’s in fine working order. ]]><![CDATA[More reason to choose fragrances carefully]]>Thu, 17 Nov 2016 10:32:00 GMThttps://www.scraigroberts.com/blog/more-reason-to-choose-fragrances-carefullyHere's more reason to think very carefully about your choices at the perfume counter. It really can affect how your smell is perceived by others, and it matters more for some than others!

Of course, one reason most of us use artificial fragrances every day is to mask malodour, our armpit smell that's gone stale. But there are other effects too. For example, we have shown that fragrances influence our self-confidence and judgments of our attractiveness even when smell cues are unavailable.

But there is no one-scent-fits-all effect here. Different fragrances suit different people. In a study with my Czech colleague Jan Havlíček, we found that some people get this spectacularly wrong. While overall artificial fragrances improve the smell of their natural body odour, for some people, their armpit odour smells worse when they use their chosen fragrance - they have selected one that clearly doesn't blend well with their own odour. More recently, my excellent ex-student Caroline Allen has shown that the right fragrance choice can emphasise the distinctiveness of our underlying body odour.

Now, Caroline has found something really very interesting about the effects of fragrances. Whereas the smell of unperfumed armpits (relatively masculine or feminine) predicts how our faces look (relatively masculine or feminine), this relationship disappears when men use fragrance. The relationship is maintained in the case of women's smell and faces. And it disappears, in men, in an interesting way: while the addition of a fragrance appears to have relatively little effect on the perceived masculinity of the odour of very masculine men, it has a strong positive effect on men whose odour and faces are at the more feminine end of the very masculine - less masculine continuum. In other words, as the Sunday Times put it, it particularly helps the "wimps".

The lesson? Don't get someone else to buy your perfume (unless you tell them exactly which one you want or use), and spend some time getting it right!

References:

Allen C, Cobey KD, Havlíček J, Roberts SC. 2016. The impact of artificial fragrances on the assessment of mate quality cues in body odor. Evolution and Human Behavior 37, 481-489. 
​http://dx.doi.org/10.1016/j.evolhumbehav.2016.05.001

Allen C, Havlíček J, Roberts SC. Effect of fragrance use on discrimination of individual body odor. Frontiers in Psychology  6, 1115.  http://dx.doi.org/10.3389/fpsyg.2015.01115

Lenochova P, Vohnoutova P, Kubena A, Roberts SC, Oberzaucher E, Grammer K, Havlicek J. 2012. Psychology of fragrance use: perception of individual odor and perfume blends reveals a mechanism for idiosyncratic effects on fragrance choice. PLoS One e33810. 
http://dx.doi.org/10.1371/journal.pone.0033810

Roberts SC, Little AC, Lyndon A, Roberts J, Havlicek J & Wright RL. 2009. Manipulation of personal odor alters men’s self-confidence and judgements of their visual attractiveness by women. International Journal of Cosmetic Science 31, 47-54.  http://dx.doi.org/10.1111/j.1468-2494.2008.00477.x​]]><![CDATA[On links between oxytocin and alcohol]]>Wed, 20 May 2015 15:53:00 GMThttps://www.scraigroberts.com/blog/on-links-between-oxytocin-and-alcoholPicture
New work suggests that alcohol and oxytocin, often dubbed "the love hormone", are more similar than we thought. For example, exposure to both compounds removes inhibitions on certain behaviours, including aggression. Interestingly, these negative effects are restricted to those with high trait aggressiveness. This raises concern over prescribing oxytocin as a general remedy to help overcome social anxiety and other antisocial behaviours, because it may have undesirable consequences on the very people who need it the most. I write more in my article Why the ‘love hormone’ may be less rosy and more rosé than we thought,  for The Conversation 
]]><![CDATA[Warning: the truth behind handshake-sniffing may bum you out]]>Fri, 06 Mar 2015 08:28:17 GMThttps://www.scraigroberts.com/blog/warning-the-truth-behind-handshake-sniffing-may-bum-you-out
After a handshake, we learned this week that we sniff our hands. But why? Hand smells are not all that interesting in themselves. This points to possibilities that you might not want to hear.

Read the full article here on The Conversation, or on IFL Science or The Guardian
]]><![CDATA[Perfume could be the riskiest gift you ever buy]]>Fri, 13 Feb 2015 08:17:37 GMThttps://www.scraigroberts.com/blog/perfume-could-be-the-riskiest-gift-you-ever-buyPicture
A gift of perfume might well be on the cards for couples as they approach Valentine's Day (or other special occasions). Read on. There are some must-knows about the science of smell and perfume that may well be new to you.

See the full article here on The Conversation, which draws heavily on our work on perfume and body odour blends: 
​
Lenochova P, Vohnoutova P, Kubena A, Roberts SC, Oberzaucher E, Grammer K, Havlicek J. 2012. Psychology of fragrance use: perception of individual odor and perfume blends reveals a mechanism for idiosyncratic effects on fragrance choice. PLoS One e33810.
​http://dx.doi.org/10.1371/journal.pone.0033810
]]><![CDATA[Migratory beekeeping, step 2]]>Fri, 20 Jun 2014 09:49:01 GMThttps://www.scraigroberts.com/blog/migratory-beekeeping-step-2hives at beans
Four of my hives newly positioned in front of stretching acres of field beans.

Things I learned during this move: at this time of year, bees in Scotland are out on the nectar razz until at least my bedtime, so I have to get up early to move them. How early? Well, 4.15 am they're already up and going out. Try again the next day... 3 am is fine! 

Happy bees, tired beekeeper.
]]><![CDATA[Dancing MHC molecules]]>Mon, 12 May 2014 10:43:36 GMThttps://www.scraigroberts.com/blog/dancing-mhc-moleculesPicture
I'm really excited to be working with Christine Hooper on a new project to depict MHC-associated mate choice through expressive dance. Christine is planning to bid for a Wellcome Trust Arts Award in June; these awards aim to "stimulate interest, excitement and debate about biomedical science through high-quality, original artistic practice". Christine makes animated documentaries and we hope to present the film and hold interactive discussions at several science exhibition venues. This promises to be a lot of fun - watch this space!
]]><![CDATA[The Family Business?]]>Sun, 11 May 2014 11:33:59 GMThttps://www.scraigroberts.com/blog/the-family-businessPicture
Struan is now Assistant Beekeeper, but needs proper gloves. 
Picture
Isla is in charge of honey processing but so far shows no interest in donning a suit....
]]><![CDATA[Ouch!]]>Tue, 06 May 2014 11:03:19 GMThttps://www.scraigroberts.com/blog/ouchPicture
I love this new paper in PeerJ - Honey bee sting pain index by body location. The author rated the painfulness of stings in different body areas relative to an "internal standard" sting on his forearm. Least painful locations were the skull, middle toe tip and upper arm (score of 2.3). The most painful areas, in reverse order were (cue drum roll): (3) penis shaft (7.3), (2) upper lip (8.7) and...... (1) nostril (9.0). I wish I had thought of doing this... well, almost. This must be a sure favourite for the Ignobel Awards. 
]]><![CDATA[Beekeeping education...]]>Mon, 05 May 2014 10:26:16 GMThttps://www.scraigroberts.com/blog/beekeeping-educationPicture
Another aim for this year is to take the next step in the Scottish Beekeepers Association examinations system. Last season I passed the Basic Beemaster Certificate, which included both practical (taking the new SBA Vice-President through one of my hives) and theory elements. Now there are only eight modules to go to work towards being a Master Beekeeper!
]]>