Do you spend money on flavoured oils, jams and chutneys? Do you know how long you should keep them, and when to throw them away? Paul Clarke from En-Place answers our questions so you can be sure you are eating food that is safe to eat!
Q: I make fresh oils using basil and other fresh herbs. I notice that some of them have developed a cloudy meshy substance, which is floating at the end of the bottle. Can I still use them?
Oils made at home by the infusion of fresh ingredients such as herbs, chilies or garlic can support the growth of deadly Clostridium Botulinum bacteria so great care must be taken in their production and storage. All oils of this nature must be kept refrigerated and should be used within three weeks of being made.
The mushy substance floating at the bottom of your oil bottle provides all the conditions that Clostridium Botulinum requires, i.e. low acid, anaerobic (without air) conditions and a food\moisture source. The Botulin toxin produced by Clostridium botulinum is a particularly nasty bacterium as digestion of even 1/1,000,000 of a gram can kill. If your homemade oils haven’t been refrigerated or have been in the fridge for more than three weeks they should be discarded immediately.
Q: How long can you keep flavoured oils?
If your oils have been produced from a food without moisture such as dried spices then they can safely be stored at room temperature, usually for up to around 12 months. The oil, which was used as a base, will carry a use by date and this can be used as a guideline. When we produce flavoured oils at En-place we have specialized production methods that ensure no moisture or food source remains in the finished product allowing for an extended shelf life and a safe product.
Q: Should you store jam in the fridge once it is opened and does the fruit content affect how long you should keep it?
As a general rule opened jams should be kept in the refrigerator at around 2-4°C and used within six weeks of opening but some jams may last considerably longer depending on the acid content of the fruit and the amount of added sugar. The shelf life is also determined by how long and how frequently the product is left at room temperature or if the product is cross contaminated any other food source such as butter or toast crumbs from a knife which is dipped into the jar. Ideally at each use the required amount of jam should be spooned into a serving bowl for the table and the jar left in the fridge. This will ensure the minimum exposure to any source of microbial contamination.
Q: I notice a mould forming on jam – is it safe to scrape it off and eat it?
Moulds are microscopic fungi that grow fastest in warm and humid conditions, but as they tolerate salt and sugar better than other micro-organisms they can also grow on jams at fridge temperatures. A mould will usually start growth on the on the top of jam where the sugars are diluted by tiny droplets of surface water and because the mould is on the surface a lot of people think it is safe to scrape it off and eat the rest – but this is not recommended.
Mould can produce toxins that can penetrate throughout the product and depending on the type of mould it can form a mycotoxin, which can cause food poisoning or may even be carcinogenic. Any product, which has a mould growth on it, should not be eaten.
Q: Where should you keep chutneys once they have been opened?
As with jams chutneys should be stored in the fridge once opened. Chutney will usually contain both acids (in the form of vinegar) and sugar, these natural preservatives will mean that if kept cool they should not mould or spoil for a considerable period. Lighter coloured chutneys may darken with age but this is not a safety concern just a natural maturing process. Chutneys are usually best around six months after production when the full flavours have developed and blended.
Paul Clarke is one of the owners of En-Place, who make speciality products for chefs.