Lactobacillus reuteri resides in the gastrointestinal tract of humans, swine, poultry and other animals. Resting cells of this species convert glycerol into a potent, broad-spectrum antimicrobial substance termed reuterin. Reuterin is a low molecular weight, neutral, water soluble compound, capable of inhibiting growth of species representing all bacterial genera tested thus far, including: Escherichia, Salmonella, Shigella, Proteus, Pseudomonas, Clostridium and Staphylococcus. Also affected, but to a lesser degree, are lactic acid bacteria belonging to the genera Streptococcus, Pediococcus, Leuconostoc, and Lactobacillus. In this report we describe a method to screen lactobacilli for production of unique antimicrobial substances and the discovery of reuterin.

To determine the prevalence of swallowing and esophageal complaints in the general population, 300 men and 300 women were asked to answer a mailed questionnaire. The participation rate was 92.5%. Complaints were reported by 35%. The most common complaints were symptoms associated with gastroesophageal reflux (GER) and globus sensation, both with a rate of occurrence of 20%. Obstruction of the bolus reported by 3% was the individual symptom that most frequently brought patients to the doctor. To validate the questionnaire and to study possible organic causes behind these symptoms, 46 persons with symptoms were invited to undergo further examination. Cineradiography of the pharynx revealed that 7 of 14 patients with symptoms of GER had abnormalities in the esophagus. Eleven of 55 patients with GER symptoms at least once a week underwent endoscopy. One case of erosive esophagitis and one case of gastric ulcer were diagnosed. Four of nine patients with obstructive symptoms had defective closure of the laryngeal vestibule shown by cineradiography. Endoscopy in four patients with obstructive symptoms revealed benign findings. Thus, an epidemiologic study of patients with swallowing symptoms documented a low incidence of serious organic disease.

Many factors contribute to a successful natural fermentation of carbohydrate‐rich food and feed products. Metabolic activities of lactic acid bacteria (LAB) play a leading role. Their ability to rapidly produce copious amounts of acidic end products with a concomitant pH reduction is the major factor in these fermentations. Although their specific effects are difficult to quantitate, other LAB metabolic products such as hydrogen peroxide and diacetyl can also contribute to the overall antibiosis and preservative potential of these products. The contribution of bacteriocins is also difficult to evaluate. It is suggested that they may play a role in selecting the microflora which initiates the fermentation. Bacteriocins are believed to be important in the ability of LAB to compete in non‐fermentative ecosystems such as the gastro‐intestinal tract. During the past few decades interest has arisen in the use of the varied antagonistic activities of LAB to extent the shelf‐life of protein‐rich products such as meats and fish. Recent findings indicate that the newly discovered Lactobacillus reuteri reuterin system may be used for this purpose.

Many factors contribute to a successful natural fermentation of carbohydrate‐rich food and feed products. Metabolic activities of lactic acid bacteria (LAB) play a leading role. Their ability to rapidly produce copious amounts of acidic end products with a concomitant pH reduction is the major factor in these fermentations. Although their specific effects are difficult to quantitate, other LAB metabolic products such as hydrogen peroxide and diacetyl can also contribute to the overall antibiosis and preservative potential of these products. The contribution of bacteriocins is also difficult to evaluate. It is suggested that they may play a role in selecting the microflora which initiates the fermentation. Bacteriocins are believed to be important in the ability of LAB to compete in non‐fermentative ecosystems such as the gastro‐intestinal tract. During the past few decades interest has arisen in the use of the varied antagonistic activities of LAB to extent the shelf‐life of protein‐rich products such as meats and fish. Recent findings indicate that the newly discovered Lactobacillus reuteri reuterin system may be used for this purpose.

One hundred wild-type strains of the genus Lactobacillus were isolated from the small intestine of newly-slaughtered pigs up to 6 months of age. Cell surface hydrophobicity and capsule formation were studied on a number of strains. Strains showing high surface hydrophobicity as measured by the salt-aggregation test and hydrophobic interaction chromatography on Octyl Sepharose were commonly found to adhere in high numbers to isolated pig intestinal epithelial cells. Heat and protease treatment of bacteria of high surface hydrophobicity, including autoaggregating strains in phosphate-buffered saline, showed a drastic decline in this surface property. Three hydrophilic strains (LBp 1044, 1068 and 1073) also showed binding to intestinal cells but at a lower level (approx. 5 bacteria/cell) as compared with the best binding hydrophobic strain (LBp 1063, approx. 11 bacteria/cell). These findings suggest that different or multiple adhesion mechanisms may be involved in the colonization of the small intestinal mucosa of pigs. Cultures of selected strains grown in liquid media rich in carbohydrates did not affect their hydrophobic cell surface character. Therefore it seems less likely that carbohydrate capsule polymers are the major determinants of intestinal colonization of lactobacilli in pigs.