Did you know? Opening the door can be fatal in serious cases. How can we prevent salmonella during the Chinese New Year?

Written by : Li Caihong, Workplace: Urumqi First People's Hospital, Title: Nutrition Chief Technician, Member of Chinese Nutrition Society, Secretary of Xinjiang Nutrition Society Youth Committee, National Registered Nutritionist

Reviewer : Zhang Yi, executive director of Xinjiang Nutrition Society, editor-in-chief of the Disease Prevention and Control Bulletin of Xinjiang Center for Disease Control and Prevention, and health science expert of the Xinjiang Health Commission

Continued public attention has made Salmonella one of the top ten hot topics of food safety and health that the public is concerned about in 2023. It is also a foodborne pathogen that is of general concern to the world. According to statistics from the World Health Organization (WHO), about 115 million people are infected with Salmonella each year, causing about 370,000 deaths worldwide.

Among foodborne diseases caused by bacteria in my country, Salmonella infection accounts for about 70%-80%, causing more than 90 million cases each year. The incidence rate is affected by factors such as the number of live bacteria, bacterial type and individual susceptibility. However, for people with higher susceptibility, such as young children, frail elderly people and patients with other diseases, even a small amount of bacteria or a weaker pathogenic type may cause food poisoning.

Salmonella has a high incidence rate and can be fatal in severe cases

Salmonella food poisoning can occur throughout the year. The interval between poisoning and onset of the disease is relatively short, generally 4-48 hours, and up to 72 hours. The poisoning mechanism is mainly that Salmonella invades the intestinal mucosa, leading to infectious poisoning.

Typical symptoms include fever, nausea, vomiting, diarrhea and abdominal cramps. Initially, there are headaches, nausea and loss of appetite, followed by vomiting, diarrhea and abdominal pain. The frequency of diarrhea can reach several times or even ten times a day. The stools are mainly watery, and a few are accompanied by mucus or blood. Severe diarrhea can lead to dehydration or even death. Infants, the elderly, and immunocompromised patients may develop severe and life-threatening bacteremia due to Salmonella entering the blood. A few may also have meningitis or osteomyelitis.

So how can we prevent it during the Chinese New Year?

1. Beware of these foods to prevent salmonella contamination

Livestock and poultry : The main source of Salmonella is that the intestinal salmonella rate of healthy poultry and livestock is high. When the resistance is reduced, the salmonella parasitic in the intestine will enter the lymph, blood, internal organs and muscles, causing secondary salmonella infection. In addition, livestock and poultry are contaminated by excrement, containers, sewage, etc. with salmonella during or after slaughter, causing post-slaughter contamination.

Dairy products : Salmonella may come from cows infected with Salmonellosis, whose dairy products are contaminated. Even dairy products from healthy cows are easily contaminated after milking.

Cooked products : The main source of Salmonella is cooked products, which may be contaminated again by contaminated containers, cooking utensils, etc., or by contaminated food handlers.

Eggs and their products : Salmonella sources Eggs and their products are more likely to be infected or contaminated by Salmonella, especially waterfowl such as ducks, geese, etc. and their eggs, with a carrier rate of 30%-40%. In addition to primary and secondary infections of poultry ovaries, yolks or whole bodies, during the excretion process, the surface of the eggshell may be contaminated by Salmonella in the feces of the anus, and Salmonella can enter the egg through the pores of the eggshell.

Salmonella is easily hidden in animal foods, especially livestock meat, followed by poultry meat, eggs, milk and cooked products, etc. Sanitary management should be strengthened to prevent food from being contaminated by Salmonella in various links such as storage, transportation, processing, cooking or sales.

2. Follow food safety tips and take preventive measures

Tip 1: Keep it clean

▶Develop good hygiene habits, wash your hands frequently, before meals and after defecation, and wash your hands carefully before preparing and handling food, and after touching animals or raw eggs.

▶Keep tableware and kitchen utensils clean and steam and sterilize them frequently.

Keep the kitchen clean and kill and isolate flies and other disease vectors. Discard unclean food that is contaminated by flies, expired or rotten and do not eat it.

Point 2: Separate raw and cooked food

▶Keep raw meat, poultry, and seafood separate from other foods, and avoid contact between raw and cooked foods to prevent cross contamination.

▶Bowls, plates and other utensils used to hold raw food must be cleaned and disinfected before they can be used to hold cooked food, cold dishes and other ready-to-eat foods.

▶Keep the cutting boards and knives used for handling raw and cooked food separate.

Key point 3: Cook food thoroughly

▶It is not recommended to eat raw or undercooked meat, eggs and aquatic products.

With the development of the economy and society and the improvement of people's living standards, the way Chinese people cook eggs has changed a lot. "Low-boiled eggs, hot-boiled eggs, boiled eggs and other low-temperature egg products are very popular, but the hidden dangers of salmonella that come with them cannot be ignored.

▶ Cooked food taken out of the refrigerator must be thoroughly heated before consumption.

Common heat treatment cooking methods at home can effectively kill the bacteria. Because Salmonella is not heat-resistant, 55℃ for 1 hour, 60℃ for 15-30 minutes, or when the core temperature of the food reaches above 70℃ for 5 minutes can generally kill common foodborne pathogens including Salmonella.

▶Cook food thoroughly before eating, especially eggs and poultry.

The weight of edible meat pieces after high-temperature treatment should not exceed 1kg, and they should be boiled for 2.5-3 hours, or the deep temperature of the meat should reach at least 80℃ and last for 12 minutes, so that the center of the meat turns gray and bloodless, so as to completely kill the Salmonella that may be present in the meat and inactivate the toxin.

Tip 4: Keep food at a safe temperature

▶It is recommended to eat cooked food promptly and store it at low temperature when not in use.

Storing food at low temperatures is an important measure to control the reproduction of Salmonella. Salmonella can reproduce in large quantities at temperatures above 20°C, and is most suitable for reproduction at 37°C. Cooked food must not be stored at room temperature for more than 2 hours.

▶Livestock meat, poultry meat, seafood, etc. can be frozen in small pieces and used in small pieces.

It is best to cut it into small pieces and pack it separately before putting it into the freezer. Take small packages of food before each processing to avoid repeated freezing and thawing, which will accelerate spoilage or cause the destruction and loss of nutrients.

▶Let the food cool down before storing it in the refrigerator, and do not store it for too long.

Since Salmonella does not decompose protein or produce indigo, there is no change in the sensory properties of food after it is contaminated. Therefore, "the refrigerator is not a safe". Whether it is refrigerated or frozen, it should be cleaned regularly. Homemade food should not be stored in the freezer for more than one month; even if pre-packaged food is within the shelf life, it is best not to exceed three months. Food that has been stored for too long should not be eaten.

Point 5: Use safe water and food raw materials

▶Go to regular supermarkets and farmers’ markets to buy fresh and safe ingredients, such as quarantined meat and pasteurized milk.

▶Safe water should be used throughout the food production process.

▶Drinking water when traveling or camping should be boiled and disinfected.

Food that has passed its expiration date should not be eaten.

Experts call for urgent prevention and control of Salmonella. Not long ago, Liu Xiumei, honorary vice president of the Chinese Society of Food Science and Technology and former chief food safety expert of the Chinese Center for Disease Control and Prevention, also proposed at the media communication meeting on the scientific interpretation of food safety and health hot spots that catering practitioners and consumers should carefully follow the "Five Key Points for Food Safety" for pathogenic microorganisms such as Salmonella, and effectively control the last barrier of food entry. Therefore, Technology Winter kindly reminds you: actively pay attention to the hazards of Salmonella, and always improve the awareness of food safety risk prevention during the Spring Festival, so that you can better spend the happy festival and share a happy year with your dear family.

References:

[1] Sun Yanming. Authoritative interpretation of the top ten hot topics of food safety and health in 2023[N]. China Consumer News, 2024-01-10(003). DOI:10.28867/n.cnki.nxfzb.2024.000064.

[2] Wang Meihua. Salmonella cannot be ignored[N]. People's Daily Overseas Edition, 2023-06-16(009).DOI:10.28656/n.cnki.nrmrh.2023.001984.

[3] Sun Changhao. Nutrition and Food Hygiene (6th Edition) [M]. People's Medical Publishing House: 200707.425-427.

[4] Luo Chen. Five key points of food safety to effectively avoid "disease from the mouth" [N]. China Food News, 2021-10-08(003). DOI:10.28137/n.cnki.ncspb.2021.001711.