In Australia over the past few weeks you have no doubt heard of a local Listeria outbreak that has 17 reported cases and caused 5 deaths so far. The outbreak has been linked back to Rockmelons sold in January 2018 and removed from the shelf in February 2018.
Bacteria’s are present everywhere in the environment, on our bodies and on the foods we eat. Usually they are not a problem but there are groups of people our community that are more susceptible to the effects of bacteria’s if they are consumed. These include those members that are developing their immunity or where their immunity is compromised. These include babies, children, pregnant women, sick and the elderly (>70).
Consumers who consume food and beverage products infected with pathogenic bacteria can either become sick from the bacteria’s themselves or from the toxins those bacteria’s produce. Viruses can also be transferred via food. If food hygiene, cooking and holding practices are not carried out properly bacteria, bacterial toxins and viruses can also be transferred to people via food.
Some of the most common food poisoning bacteria found in food and beverage products in are listed below. Each type listed below has an incubation period which is the time between consumption and when symptoms will first begin to appear –
Salmonella – Causes Gastroenteritis, typical incubation period 6 – 72 hours.
Campylobacter – typical incubation 2 – 5 days
E coli or Escherichia coli – typical incubation 3 – 4 days
Listeria monocytogenes – typical incubation period of 70 days.
Hepatitis A – typical incubation 14-28 days
Norovirus – typical incubation 2 days
Rotavirus – typical incubation 2 days
Bacillus cereus – typical depending on type 30mins to 15 hours
Staphylococcus aureus toxin – typical 1 – 6 hours
Clostridium perfringens toxin – typical 6 – 24 hours
It’s very important to note that the onset of the symptoms for each of these above illnesses can vary greatly dependant on the type of pathogenic bacteria involved. Some can be only a few hours after consumption and others can take weeks before the symptoms appear. If you do have symptoms of nausea, diarrhea, headaches, abdominal cramps, vomiting and fever please ensure you see your local GP. For more information please see the link below –
Foods that are commonly the source of bacterial infections include –
Meat, Poultry and Seafood raw and undercooked
Pre-cooked cold chicken
Cold Dressed salads
Cold Deli meats
Raw or smoked seafood
Meats, stews and gravies
Sprouts including alfalfa and sprouted legumes
How Do Bacteria’s and Bacterial Toxins grow in foods?
All foods contain a level of bacteria naturally occurring on and in the food. Bacterial growth commonly occurs when bacteria’s already present in the ingredients being used (such as salmonella on chicken or eggs) are used in recipes and allowed to sit at temperatures where the bacteria can multiply and increase to the point where they will make consumers sick. If you start with a low level of bacteria in the first place you have a better chance of ensuring the safety of the food that you serve to your friends and family. When purchasing ingredients from your local supermarket such as dairy, chicken, meat or seafood ensure the temperature of these ingredients does not rise too much between the supermarket and your home refrigerator. Use chiller bags when transporting by car to keep the temperature as low as possible. When preparing, holding, storing and re-heating foods it’s very important to ensure that basic hygiene is followed at all stages. There are a number of simple rules to follow –
- Before starting to prepare foods ensure that all surfaces you are using are clean, cutting boards, knives are also clean. Ensure your hands are washed with soap and water focusing around the nails, the backs of your hands and in between your fingers. Sanitiser is not necessary as long as your hands are washed well with soap.
- Store meats on the bottom shelf of your fridge to prevent drips or spills onto other foods.
- Defrost frozen meats overnight in the fridge not on the kitchen bench.
- Don’t cut meats and vegetables on the same board and with the same knife. Use separate boards and utensils.
- Ensure all vegetables and fruits are cleaned properly with all the soil completely removed before cooking. Use a clean dedicated brush to scrub potatoes and root vegetabales free of dirt. Clean the brush under running water and allow the brush to air dry fully. You don’t need to remove the skin of vegetables as we know that this destroys many of the vitamins and minerals found in the layers just underneath the skin but do ensure that all the loose dirt has been fully removed. This is really important when cleaning vegetables such as mushrooms, leaks and lettuce that may have soil contamination hidden in the layers throughout the plant.
Cooking and Holding Temperatures
There is a danger zone when it comes to bacteria. When storing ingredients and holding cooked foods ensure that cold foods are kept cold or <5C and that hot foods are kept hot > 60c. Try to move as quickly as possible between the danger zone so heat foods quickly and cool foods as quickly as possible to try to minimise the time it’s left in the danger zone. This is the temperature zone where most bacteria’s will multiply and reproduce. In some cases the bacteria’s produce a toxin which is not killed by heat and will remain in the food after heating even when the bacteria itself has been killed.
Ensure that you use a food thermometer when checking cooked meats to ensure the internal temperature is over 70c. I always heat my meats to 75 for roasts just to make sure and over 80 for bone in pieces such as chicken drumsticks.
Food manufacturers are required to follow strict guidelines when it comes to the hygiene and cleanliness of both staff and their facility, and they comply and record strict cleaning and sanitation procedures for their equipment and their plant. Microbiological, yeast and mould testing is also carried out before a product is released to the consumer for high risk foods. The source of many food poisoning outbreaks in our communities are commonly traced back to small businesses where outbreaks have occurred due to poor personal hygiene, insufficient cooking temperatures and the use of equipment that hasn’t been properly cleaned or sanitised. When eating out, try to pick reputable businesses that have good reviews and clean premises.
Copyright 2019 Food Facts for Healthy Eating