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Objective: Mobile knee spacers can be utilized in the first stage of a two-stage exchange in periprosthetic joint infection or septic arthritis of the knee to prevent soft tissue contraction, enable local antibiotic elution, and improve patient mobility. Commercially made moulds enable the surgeon to prepare a reproducible spacer design and match the preparation of the arthroplasty, which will be carried out in a second step., Indications: Periprosthetic joint infection of the knee and severe cases of septic arthritis of the knee with advanced destruction/infiltration of the cartilage., Contraindications: Antibiotic resistance of the microbiological pathogen to available antibiotic agents, incompliant patient, large osseous defect preventing proper fixation, known allergy to polymethylmethacrylate (PMMA) or antibiotic, severe soft tissue damage with high ligament instability, especially deterioration of extensor mechanism and insufficient patella/quadricep tendon., Surgical Technique: After thorough debridement and removal of all foreign material, cutting blocks are used to shape femur and tibia to the implant design required. Using a silicone mould, PMMA with suitable antibiotics is moulded into the shape of the future implant. After polymerization, the implants are fixed onto the bone with additional PMMA without pressurize for the sake of easy removal., Postoperative Management: Partial weight bearing with no restriction of flexion/extension while spacer is in place; second stage reimplantation as soon as infection is controlled., Results: In all, 22 cases were treated, mostly with a PMMA spacer containing gentamicin and vancomycin. Pathogens were detected in 13 of 22 cases (59%). We observed two complications (9%). Twenty of 22 patients (86%) were reimplanted with a new arthroplasty; 16 of the 20 patients remained revision-free and infection-free at the last follow-up (average time to follow-up 13 months, range 1-46 months). Average range of motion in flexion and extension at follow-up was 98°., (© 2023. The Author(s), under exclusive licence to Springer Medizin Verlag GmbH, ein Teil von Springer Nature.)

The genotoxic potential of sorbic acid and potassium sorbate was investigated in vivo and in vitro. Oral administration of sorbic acid (up to 5000 mg/kg body weight) did not induce sister chromatid exchanges or the formation of micronuclei in bone marrow cells of mice. Intraperitoneal treatment of rats with 400-1200 mg potassium sorbate/kg body weight did not alter the elution profile of DNA from isolated liver cells in the in vivo alkaline elution assay. Sorbic acid did not induce DNA repair in cultured human A549 cells in the unscheduled DNA synthesis (UDS) assay. In vitro incubation of the cells with 1-1000 micrograms potassium sorbate/ml, in the absence or presence of rat liver homogenate, did not result in the formation of DNA single-strand breaks in the alkaline elution assay. These results demonstrate that sorbic acid and its potassium salt are not genotoxic in vivo or in vitro. In contrast to sorbic acid and potassium sorbate, sodium sorbate is very sensitive to oxidative degradation; the main oxidation product was identified to be 4,5-oxohexenoate, which was mutagenic in the Ames test.

Because of their physiological inertness, their effectiveness even in the weakly acid pH range and their neutral taste, sorbic acid and its salts have become the leading preservatives in the food sector throughout the world over the past 30 years. The most commonly used products are sorbic acid itself (E200) and potassium sorbate (E202). In many countries sodium sorbate (E201) and calcium sorbate (E203) are also permitted. Sorbic acid is sparingly soluble in water, sodium sorbate has better solubility, and potassium sorbate is very freely soluble and can be used to produce 50% stock solutions. The soluble sorbates are preferred when it is desired to use the preservative in liquid form, or when aqueous systems are to be preserved. Sodium sorbate in solid form is unstable and very rapidly undergoes oxidation on exposure to atmospheric oxygen. It is therefore not produced on the industrial scale. Aqueous solutions of sodium sorbate remain stable for some time. Calcium sorbate is used in the manufacture of fungistatic wrappers because it is highly stable to oxidation, but this use is very limited. Sorbic acid and sorbates can be directly added into the product. The products can be dipped or sprayed with aqueous solutions of sorbates. Dusting of food with dry sorbic acid is also possible but less recommended because sorbic acid irritates the skin and mucous membranes. Sorbic acid and particularly calcium sorbate can be used as active substances in fungistatic wrappers. A general survey of the numerous uses of sorbic acid in the food sector will be given. Some fields of application will be discussed that are either unimportant or not permitted in the U.K.

Preservation of foodstuffs has always been a necessity for a number of reasons: the durability of food is limited, numerous foodstuffs are only available during a short harvesting season, the transport routes of food or raw materials from the production site to the consumers are continuously increasing in length and the consumers in modern society characterized by division of labor and changed shopping habits increasingly insist on buying durable products. Beyond this, there are medical-hygienic efforts aimed at inhibiting the growth of micro-organisms in food. The hazard to health which many bacteria carry, has been long known. Recently, a number of fungi have been shown to form toxins during their growth on foodstuffs. There are two methods of food preservation: the physical and the chemical. The greater proportion of foodstuffs is rendered durable by physical procedures: drying, cooling, deep-freezing and heating. But chemical preservation also plays a prominent role. The use of preservatives is often combined with physical methods. The application of preservatives has a long history, such as the use of common salt, smoke or sulfur dioxide. Some of these agents, such as benzoic acid, are achievements of the last century. Others, such as propionic acid and sorbic acid, result from research during the last few decades. The preservatives now in use have been thoroughly tested for their toxicological properties. Their use in the food industry is subject to stringent legal regulations. The consumer can be certain of not running any risk by partaking foods which contain preservatives.

Potassium sorbate at a concentration of 200-400 ppm inhibits mycotoxin forming Aspergillus versicolor at a pH of 5.7-5.9 in culture media and fermented sausages.

Analyses of 45 samples of sour dough and various kinds of bread have shown that no appreciable amounts of propionic acid are formed during sour dough fermentation. Bread has no natural propionic acid content.

A survey is given of synthesis, chemical and physical properties, and hydrolytic stability of the new sweetener Acetosulfam (3,4-Dihydro-6-methyl-1,2,3-oxathiazin-4-one-2,2 dioxide potassium salt).

Food additives serve the consumer and are a necessity for food retailers and producers. Additives, such as vitamin D and iodine, increase the nutritional physiological value of foodstuffs. Additives, which improve food preservation by preventing microbiological deterioration are especially important. Some additives are added during food production and have no further use in the finished product. They are no longer present (solvents, clarifying agents). With regard to health, many food additives are better tested than most foods.