Most of us learned our kitchen habits decades ago and have carried them forward without much thought. The sniff test. The plate of leftovers left on the counter to cool while we watch the news. The bag of salad opened on Monday and finished on Friday. For most of our lives those small shortcuts caused no trouble at all. After 50, and particularly after 65, the margin for error narrows: the same bacteria that once caused a bad day can now cause a hospital admission. This is not about becoming anxious in your own kitchen. It is about knowing which handful of habits genuinely matter, and quietly adjusting them.
TL;DR
- The immune system ages, stomach acid weakens, and common medications reduce your natural defences, so foodborne infection hits harder after 50 and much harder after 65.
- Campylobacter is Ireland’s most commonly notified foodborne infection, with more than 2,300 cases reported in the first half of 2025 alone.
- Listeria deserves particular respect: it grows in the fridge, symptoms can appear anywhere from three to 70 days later, and the Food Safety Authority of Ireland (FSAI) names people over 65 as an at-risk group.
- Chilled ready-to-eat foods carry most of the listeria risk: sandwiches, prepared salads, coleslaw, smoked salmon, pâté, deli meats and soft cheeses.
- Three changes cover most of the risk: keep the fridge at 5°C or below, respect use-by dates on chilled ready-to-eat food, and cool leftovers quickly rather than slowly.
Why the rules change as you age
Three things shift, and they compound.
The first is immunosenescence, the gradual ageing of the immune system. Your body still fights infection, but it mounts a slower, less coordinated response. A dose of bacteria your immune system would have cleared quietly at 35 can establish itself at 70.
The second is stomach acid, a genuine barrier that kills many organisms before they reach the intestine. Acid production tends to fall with age, and further still if you take a proton pump inhibitor such as omeprazole or lansoprazole for reflux. These are among the most commonly prescribed medicines in Ireland, and while often entirely appropriate, they remove a layer of protection.
The third is that infection rarely stays contained. Dehydration from a few days of vomiting and diarrhoea is far more consequential if you also take diuretics, ACE inhibitors or metformin, and a gut infection can tip a stable long-term condition into an unstable one within 48 hours.
What is actually circulating in Ireland
The Health Protection Surveillance Centre (HPSC) tracks notified cases. Campylobacter remains by far the most commonly reported, with 852 cases in the first quarter of 2025 and 1,449 in the second, both up on the same periods in 2024. Some of that rise reflects a change in how cases are notified from the start of 2025, so read the trend with care, but the volume is substantial. Salmonella notifications held steady at 94 in the second quarter of 2025, and verotoxigenic E. coli cases rose to 282, with 107 people hospitalised.
Campylobacter overwhelmingly comes from raw poultry, and it does not need much: a few cells transferred from a chicken package to a chopping board, or to the hands that then dress a salad. This is why the advice never to wash raw chicken matters. Washing does not remove campylobacter, it sprays it across your sink and worktop.
Listeria: the one that behaves differently
Most food safety advice assumes bacteria multiply when food is warm. Listeria monocytogenes breaks that rule: it grows slowly at refrigeration temperatures, so a contaminated chilled product becomes more dangerous the longer it sits in your fridge, not less.
The FSAI identifies pregnant women, newborns, older adults and people with weakened immune systems as most at risk of severe illness. For everyone else listeriosis is usually a mild flu-like episode. In an at-risk group it can cause bloodstream infection or meningitis.
Two features make it awkward to spot. Symptoms usually appear around three weeks after exposure, but the range runs from three days to 70 days, so by the time you are unwell the food is long gone and the connection is invisible. And the foods involved are not the ones people instinctively distrust. The FSAI’s list for vulnerable groups is: sandwiches, prepared salads, coleslaw, smoked salmon, deli meats, pâtés, and soft or semi-soft cheeses. All of it looks, smells and tastes perfectly fine.
Ireland had a listeriosis outbreak in 2025 linked to ready-to-heat meals, resulting in a death and a substantial product recall. In response, stricter EU legal limits for listeria in ready-to-eat foods came into force on 1 July 2026, with the FSAI issuing new guidance to help food businesses comply. That tightens the supply side. The domestic side is still yours.
The practical changes worth making
Check your fridge temperature. Ready-to-eat chilled food should be held at 5°C or below. Most home fridges are warmer than their owners assume, particularly the door shelves. A fridge thermometer costs a few euro and is the single highest-value purchase in this whole article. Keep chilled ready-to-eat items on a middle shelf, not in the door.
Treat use-by dates as a hard stop. Best-before dates are about quality and there is room for judgement. Use-by dates on chilled ready-to-eat food are about safety, and the sniff test cannot detect listeria. Operate a first-in, first-out system so older items sit at the front.
Cool leftovers fast, not slowly. Get cooked food into the fridge within two hours, dividing a large pot into shallow containers rather than leaving the whole thing on the hob. If you batch cook, as many people living alone sensibly do, label containers with the date and reheat only once, until piping hot throughout.
Separate raw and ready-to-eat. Different chopping boards, raw meat on the bottom shelf so nothing drips onto food below, hands washed between the two. This is where campylobacter is won or lost.
Be stricter when you are already unwell. During chemotherapy, on immunosuppressants, or while recovering from surgery, it is reasonable to avoid higher-risk chilled ready-to-eat foods entirely and stick to freshly cooked meals.
When to contact your GP
Most food poisoning settles within a few days with rest and fluids. Contact your GP, or the out-of-hours service, if there is blood in the stool, a fever above 38°C, vomiting that prevents you keeping fluids down, symptoms lasting more than three days, or signs of dehydration such as dizziness on standing and passing very little urine. Seek help urgently if there is confusion, severe abdominal pain, or a rapid deterioration, as these can indicate sepsis.
Ring early rather than late if you take diuretics, blood pressure medication or metformin, as some may need to be paused temporarily during an acute illness. The HSE’s undertheweather.ie has straightforward self-care guidance, and suspected food poisoning from a commercial premises can be reported to the HSE’s Environmental Health Service.
Where to find reliable information
The FSAI maintains the national food alert and recall list, worth glancing at occasionally, and Safefood, the all-island body for food safety and nutrition, runs the annual Safe2Eat campaign.
None of this asks you to eat differently, only to handle food with the care your body now warrants. A fridge thermometer, a firm line on use-by dates, and leftovers chilled inside two hours will do more for your health this year than most supplements on the shelf.
At Críonna Health we believe ageing well is built from small, repeatable decisions rather than dramatic ones. This is one of the smallest and most reliable.
This article is for general information and does not replace advice from your GP, pharmacist or dietitian.
📷 Photo by THLT LCX on Unsplash
