The hygiene rules for yogurt making are simple enough:
- Have a good handwash using hot water and soap before starting work.
- Always use clean utensils; if in doubt wash in hot soapy water again and rinse.
- Avoid breathing over open containers.
- Avoid touching your face, hair etc; if this happens, have another handwash.
- Handle equipment at a modest distance (you really don’t want eyelashes or hair in the yogurt).
- Keep young kids and pets at a distance if necessary – the task requires concentration!
- Wash the measuring cylinder etc in hot soapy water after use, rinse and drain to dry.
In our case it is also necessary (in order to prevent contamination) that the wine bottle stopper is kept in place in the top of the tube whenever the funnel is not being used. If it is solid metal, the stopper should be wiped down with a clean cloth every other day and given a quick check for damage that could harbour unwanted bacteria. If flies or other insects are a problem, the funnel and any jug or vessel used to transfer milk should be covered when not in use.
In general, your best guarantee of avoiding unwanted outcomes is given in the points mentioned above and to use your eyes and sense of smell; keep a look out for local discolouration in the final product (unlikely to cause harm but unsightly) and any strong odours; a faint sweet odour of toffee is acceptable but a cheesy smell is not and suggests air is getting into the tube (though this was not encountered in the 12 month trial).
Official guidance on procedures in the kitchen is available from the Food Standards Agency click here