How mucky is it?

For today’s food hygiene and safety lesson I’m doing an experiment to demonstrate the hazards in the cookery room and make the textbook stuff more interesting. I’ve borrowed some Petri dishes from Michael, the lab assistant, and filled them with agar jelly which I’ve made from a packet of agar, bought from London’s ChinaTown. It’s the perfect medium for growing bacteria and mould. The school science lab probably has some agar powder but a trip to London’s ChinaTown is my weekend treat, along with a lunchtime visit to a dim sum restaurant. I dissolve strands of agar in warm water and pour the lqiuid into the Petri dishes to set. Mary, my Hong Kong friend taught me how to use agar to make the most delicious Chinese almond jelly and I might make some for supper.

The class sits round my demonstration table in front of a row of plastic dishes filled with clear, gelatinous jelly.

‘This jelly is made from agar, which is a seaweed and we’re going to use it to grow some germs. Where do you think we will find the most germs – or bacteria a new word – in this room?’

They stare back in silence. Their eyes have a fierce, quiet message.

‘We want to cook not do this stupid science stuff.’

I scratch BACTERIA AND MOULD on the roller board.

‘Let’s start with unwashed hands. Carol – press your fingers onto this jelly and let’s see why we need to wash our hands.’

A low moan comes from Bert. 

‘Listen – the quicker we do this experiment, the sooner you can cook!’

The class glares at Bert to shut up.

‘Now I’ll put a lid on the dish, seal it with tape and label it Fingers.’ 

‘What else might be dirty in this room?’

Stupid, stupid question. I scowl at Bert, ignore the mutterings and hope I didn’t hear ‘knickers’.

‘What about dishcloths? Someone fetch me one.’

Len presses a soggy dishcloth firmly into the jelly leaving a knitted imprint. Lid on, sealed, taped, labelled Dishcloth.

‘One more dirty thing please.’

Groan, mutters.

“Hair!’ Some strands of hair get passed forward and stuck to the jelly, then sealed and labelled Hair.

‘Linda – suggest something else we can test for bacteria.’

“Spit miss.’ 

Sensible, sensible Linda who comes to this class under sufferance. She’s too meek to ask to change to technical drawing, and gets on with her cooking quietly out of the radar of the boys’ humour.

‘Good idea – who’d like to spit into the Petri dish?’

Ray’s hand shoots up.

‘OK Ray – just take this dish over to the sink and spit into it. Put on the lid and label it.’ 

I don’t want to get anywhere near Ray’s spit, thankyou.

Ray aims a glob of spit like a practised archer and lands it in the middle of the jelly. 

Sealed, taped and labelled Spit, it joins the windowsill line up of Fingers, Dishcloth, Hair behind my desk. Along with a Do Not Touch sign.

‘This experiment will show you the importance of hand washing before cooking, why I wash the dishcloths in the twin tub each night and why long hair is tied back. And why catering kitchens have notices up saying ‘Don’t Spit!’’

‘Just to finish I want to show you how mould grows on food.’

Groan, moan.

I seal some slices of damp Mother’s Pride bread in a large polythene bag. Another bag contains my lunchtime apple core, then both bags join the row of Petri dishes on the windowsill under the Do Not Touch sign.

There’s mumblings of ‘Miss! Please! let’s cook.’ 

So it’s aprons on, hair back, hands rather well washed and onto making Cornish Pasties, while the Petri dishes pursue the task of delivering my hygiene message.

Each morning of the following week I peer through the Petri dish lids hoping for change – just like hoping that yeast will ferment in a freezing room. Each day I am rewarded with expanding rings of colour as the bacteria feed and grow.  Alongside the circles are grey, furry splodges of fungal spores and after a few days there’s surprises in the plastic bags – blue fronds of mould sprout on the damp bread and the apple core rots and turns brown.

Before the start of their cooking lesson, I proudly pass round a tray containing the sealed Petri dishes, each showing circles of coloured growth and each with weird odours leaking through the lids.

‘Look class. See how hands, dishcloths, hair and spit all contain bacteria – those coloured rings – and that grey stuff, mould. And that’s why we clean up to cook.’

I hold up the two mouldy, smelly bags of bread and apple core.

‘Ugh, Miss – we know – don’t eat mouldy stuff.’ Ray is being clever but not smart enough.

“Actually Ray, some moulds are good. Like Blue Stilton cheese.’

They hate blue cheese. Only Cheddar is edible.

At the end of school I scrape the contents of the Petri dishes into a bin bag, wash out the dishes and return them to Michael along with a lemon curd tart on a doyley on a plate. I’m sure he’ll be pleased.

“Thanks Michael – we got some really interesting bacteria and other things growing in them.’

‘Growing in what? Where are the contents, Jenny?’

‘In the bin in my room.’

‘What! You know that could be SO DANGEROUS! Growing bacterial cultures in your classroom, throwing them in the bin and then washing the dishes in the sink. Haven’t you heard of Black Death and Plague?! Bring me your bin bag to dispose safely and I’ll need to autoclave these Petri dishes.’

I’m not telling him where my mouldy bread went but I do wonder if he’ll eat the tart.