Recently, a news incident involving the infection of Listeria monocytogenes with meningitis caused by consuming frozen meat in a refrigerator has attracted the attention of netizens. Lv Fulin, Deputy Chief Physician of the Emergency Department of Jiangbei Branch of Southwest Hospital of Army Medical University, introduced to reporters that in summer, refrigerators are used more frequently and are more likely to breed Listeria monocytogenes, known as the "refrigerator killer". What are the characteristics of Listeria monocytogenes? Why is it called the 'refrigerator killer'? What diseases can be caused after infection? With these questions in mind, a reporter from Science and Technology Daily interviewed relevant experts. Cold resistant and highly invasive, once infected, the consequences can be severe. Many people believe that low temperature equals sterility, but this is actually a misconception. ”Liu Wei, Deputy Chief Physician of the Infection Department of Jiangbei Branch of Southwest Hospital of Army Medical University, told reporters that Listeria monocytogenes, a highly resilient foodborne pathogen, is highly cold resistant. In low temperature environments (usually around 4 ℃), the growth of common pathogenic bacteria is inhibited, but Listeria monocytogenes can survive for a long time in a frozen environment of -20 ℃, and the refrigerator compartment is actually a suitable "breeding ground" for its growth. In addition, Listeria monocytogenes has strong tolerance to dry and high salt environments, and is widely present in soil, water, decaying vegetation, and animal feces. It is highly susceptible to cross contamination by contaminated raw materials, processing environments, or personnel into the food chain and continues to proliferate in refrigerators. Liu Wei said that if soft cheese, ready to eat meat (ham, sausages, refrigerated meat sauce), ready to eat salads, unpasteurized dairy products, pre cut fresh fruits and vegetables, and other directly consumed foods are contaminated with Listeria monocytogenes in the refrigerator and not heated before consumption, people will experience symptoms similar to influenza or gastroenteritis once they consume them, such as fever, muscle soreness, nausea, vomiting, diarrhea, etc. Lv Fulin pointed out that Listeria monocytogenes has strong invasiveness. It can both hide in immune cells and infiltrate the central nervous system, as well as cross the intestinal barrier into the bloodstream, directly damaging the endothelial cells of the blood-brain barrier, breaking through the blood-brain barrier, causing meningitis, encephalitis, and severe neurological symptoms such as severe headaches, neck stiffness, blurred consciousness, convulsions, and balance disorders in patients. Chen Yin, Deputy Chief Physician of Obstetrics and Gynecology at the Jiangbei Branch of the Southwest Hospital of the Army Medical University, specially reminds that Listeria monocytogenes "prefers" to attack the elderly, pregnant women, newborns, as well as immunocompromised individuals such as chronic disease patients and cancer patients, resulting in more serious consequences. For example, the risk of contracting Listeria monocytogenes in pregnant women is several times higher than that of the general population. Listeria monocytogenes can cross the placental barrier, causing natural miscarriage in early pregnancy, fetal death or placental inflammation in mid pregnancy, and premature birth or neonatal sepsis in late pregnancy. Pay attention to separating raw and cooked, follow the heating rule of 74 ℃. How to prevent Listeria infection in summer? Liu Wei stated that controlling the source is the primary line of defense. Household refrigerators should ensure that the temperature in the refrigeration and freezing compartments does not exceed 4 ℃ and -18 ℃ respectively, and thoroughly clean the interior every month. The purchase of raw and cooked food should choose reliable merchants. After putting it in the refrigerator, the raw and cooked food should be separated, that is, raw meat and seafood should be placed in covered containers or sealed bags, and placed in the bottom drawer of the refrigerator to prevent juice from contaminating the food below; Cooked and ready to eat foods should be stored on the upper level of the refrigerator compartment or in dedicated drawers. Space should be left in the refrigerator to ensure air circulation, and ready to eat food, cooked food, and cut fruits should not be stored for more than 3 days; Leftover food should be refrigerated within 2 hours after cooking and thoroughly heated before consumption. Food processing also needs to strictly prevent contamination. Liu Wei suggested that Listeria monocytogenes can also survive at 0-45 ℃, and its inactivation can follow the "74 ℃ heating rule" - when cooking dishes such as meat, eggs, seafood, etc., the center temperature should be above 74 ℃, and leftover dishes should be reheated by boiling. All perishable foods should be consumed as soon as possible to reduce their residence time in the dangerous temperature range (4 ℃ -60 ℃). After handling raw food, hands, cutting boards, knives, and countertops should be thoroughly washed with hot soapy water for at least 20 seconds. Raw and cooked food utensils should be used separately. For pregnant women, the elderly, and those with low immunity, Chen Yin suggests avoiding high-risk foods such as non pasteurized soft cheese, undercooked refrigerated ready to eat meat, refrigerated smoked seafood, fresh dairy products, and pre made salads containing raw meat, seafood, and eggs as much as possible. Once the above-mentioned population experiences fever, diarrhea, abnormal fetal movement, etc., they should seek medical attention immediately and inform the doctor of their dietary history. Liu Wei said that there is no need to panic when facing Listeria monocytogenes. As long as we recognize its harm and strictly implement scientific preventive measures, we can effectively resist the "refrigerator killer" and enjoy a healthy summer with peace of mind. (New Society)