Half of the poisoning in processed food is caused by bacteria and the rest by noroviruses. American scientists have developed safe food preparation procedures that can protect against them. Scientists have discovered natural ways of preserving food and a bacteriophage that destroys bacteria that contaminate food and cause fatal infections.
A team of scientists from the Centers for Disease Control and Prevention, led by Dr. John A. Painter, investigated the root causes of common food poisoning and severe poisoning, even causing death. As it turned out, more than half of the poisonings concern food prepared at home, other sources of pathogens are most often poorly stored semi-finished products and ready meals.
According to Dr. Patricia M. Griffin, who participated in the study, homemade preserves are treated according to the principle that eating from home cannot harm, which in many cases is not true. As it turned out, salads – both homemade and prepared in an industrial way – caused the most poisonings. The most serious poisonings, including fatalities, were mainly caused by the consumption of chicken products contaminated with bacteria.
As researchers found, 54 percent. poisoning is caused by a bacterial origin, resulting from too long storage of food outside the refrigerator, generally too long storage of refrigerated food, freezing food for long-term storage not immediately after preparation but after some time (sometimes even 56 hours).
However, as much as 46 percent. poisoning was caused by noroviruses. One could avoid such poisoning by washing hands for more than 20 seconds with liquid soap and ordinary soap. Meanwhile, the people preparing the food were content to rinse their hands with warm water, without washing them or washing them for a very short time, e.g. 5-7 seconds, before any disinfecting effect of the liquid or soap was revealed.
As the researchers noted, there were relatively few poisonings with pork or beef preparations. Food preparers paid more attention to the fact that meat can be spoiled or contaminated and eating it would be very dangerous to health. Meanwhile, according to consumers, chicken meat does not pose such a threat, so its condition was assessed very briefly.
Based on this research result, researchers developed a food evaluation guide, posted on www.HomeFoodSafety.org. When using various types of food storage and preservation methods, it is necessary to follow safe procedures for its preparation. Among them are recommendations:
– Cold water washing of all fruit and vegetables, including those from discount stores and supermarkets.
– Ejecting the outer leaves of cruciferous plants, detecting darkened, bruised or damaged areas. Noticing even small areas of mold disqualifies the whole fruit or vegetable.
– Using separate sets of knives – for fruit and vegetables, and for meat and fish. Other knives should be used for cutting all food products that are eaten without heat treatment, such as yellow cheese (in Poland also white cheese). Ideally, these knives should have colored handles so that they cannot be confused.
– Do not use plant parts such as alfalfa sprouts, mung beans or clovers bought on organic shelves in supermarkets and discount stores for direct consumption. They should be boiled or scalded.
– For all types of meat, the expiry date and condition must be carefully checked, both if the meat is fresh and chilled. Store briefly, in the coldest part of the refrigerator. Prepare dishes from them 1-2 days after purchase for fresh chicken or pieces derived from it, in the case of meat – within 3-4 days. Prepared meals, if not intended for direct consumption, should be immediately frozen when they have cooled down sufficiently to allow them to be put in the refrigerator. Store up to 4 days. Do not re-freeze food or frozen food that has thawed.
Defense by attacking anthrax
In turn, an international research team led by prof. Holly Ganz from the University of California has discovered a new biological way to tackle the risks of food poisoning and even terrorist attacks using biological weapons. Scientists isolated a previously unknown bacteriophage named Tsamsa from the corpses of a killed zebra in Etosha National Park in Namibia. This bacteriophage attacks both the spore and mature form of the anthrax bacillus – Bacillus anthracis – one of the most dangerous bacteria that can contaminate food, also used in attacks with biological weapons.
Bacillus anthracis spores are very persistent – they survive in the soil for a very long time. They can become infected by ruminants such as zebra during grazing. Infection causes the development of bacterial forms from the spores and, consequently, the death of the animal. However, if anthrax infections were common, there should be a real hecatomb of animals, and the carcass should contaminate the surrounding soil for a long time. Meanwhile, it does not happen – the victims of infections are the animals, both weak and sick, and the bacteria released from them do not contaminate the soil to a large extent.
The cause is precisely Tsamsa – a large bacteriophage, a virus that attacks bacteria. It infects both mature forms of bacteria and spores, causing their rapid destruction. It also attacks Bacillus cereus, one of the bacteria responsible for contaminating food. It is determined by endolysin, an enzyme that causes hydrolysis, i.e. the dissolution of murein, one of the main components of bacterial cell walls and membranes. It is characteristic of bacteriophages, and Tsamsa has an extremely complex form of this enzyme that can destroy the cell walls of many types of bacteria. According to prof. Jochen Klumpp from ETH Zurich, co-author of the publication, thanks to Tsamsa’s discovery, scientists can create the first promising phage therapy based on this phage or isolate endolysin from it in order to produce an auxiliary drug in antibiotic-resistant bacteria therapy, cooperating with a new class of antibiotics based on e.g. on nanoparticles. However, according to prof. Klumppa, phage therapy is more promising and could be introduced sooner – in just 2-3 years. Such therapies could heal people who, for example, have eaten poisoned food and are suffering from a serious, life-threatening bacterial infection.
In turn, a team of scientists from the University of Minnesota, led by Prof. Dan O’Sullivan discovered a new natural antibiotic called lanbiotic. Lanbiotic is a substance of bacterial origin, produced by harmless gram-negative bacteria, protecting them against invasion of bacterial pathogens of the genus Escherichia coli. Lanbiotic is a peptide that weakens pathogen cell walls so much that they cannot survive.
Lanbiotic may become an auxiliary drug in antibiotic therapies. Creating a potent antibiotic based on it will require synthesizing a stronger version of it. However, it can already be used to protect food, especially processed and frozen food. Already today, it is possible to create procedures for the protection of lanbiotic-based frozen seafood, ready meals, eggs and dairy products, processed and raw meat, carbonated drinks and salads. Lanbiotics have no side effects, as they are produced by some types of human intestinal bacteria, they are non-toxic and would be easy to apply. Scientists believe that the methods of food protection based on them will appear on the market in about 3 years.
Tekst: Marek Mejssner