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Lactobacillus acidophilus – Definition, Morphology, Classification, Habitat

What is Lactobacillus acidophilus?

  • Lactobacillus acidophilus, often referred to as L. acidophilus, is a significant species within the Lactobacillus genus. This genus encompasses a diverse group of Gram-positive, non-sporing rods that produce lactic acid as their primary metabolic end product from carbohydrate fermentation. Characteristically, L. acidophilus thrives in acidic environments, reflecting its name, which combines ‘acidum’ (Latin for acid) and ‘philus’ (loving), indicating its affinity for low pH conditions.
  • This bacterium is naturally present in the human microbiota, colonizing the oral cavity, gastrointestinal tract, and female genitourinary tract. Besides human hosts, L. acidophilus is also found in plant materials and various foodstuffs, particularly in fermented milk products like cheese and yogurt, and in fermented beverages such as wine and cider. Its presence in foods can enhance flavors or indicate spoilage.
  • Most Lactobacillus species, including L. acidophilus, are non-pathogenic and are often consumed as probiotics. These probiotics are known for their health benefits, including the prevention of certain infections. However, there are rare cases of infections such as bacteremia attributed to L. acidophilus. The incidence of such infections is low, representing a small fraction of all cases of infective endocarditis and bacteremia.
  • The bacterium was first isolated from infant feces in 1900 by Ernst Moro, initially named Bacillus acidophilus. Subsequent taxonomic refinements led to its reclassification under the Lactobacillus genus. The species exhibits optimal growth at a pH value of around 5.5 and prefers temperatures close to human body temperature.
  • L. acidophilus displays antagonistic properties against various pathogens including Staphylococcus aureus, Escherichia coli, Salmonella typhimurium, and Clostridium perfringens. It is particularly effective against S. aureus and C. perfringens, both of which are Gram-positive bacteria, compared to the Gram-negative bacteria in the list. Additionally, it has been found to reduce oral plaque formation caused by Streptococcus mutans.
  • Regarding industrial applications, L. acidophilus is widely used in the dairy industry and for producing probiotic foods. It is also included in various beverages and dairy products as an approved ingredient by regulatory bodies like the US Food and Drug Administration, particularly after extensive studies on specific strains such as Lactobacillus acidophilus NCFM. The genome of L. acidophilus has been sequenced, providing further insights into its characteristics and potential applications.

Classification of Lactobacillus acidophilu

  • Taxonomic Domain and Phylum: Lactobacillus acidophilus, a significant species in the Lactobacillus genus, belongs to the domain Bacteria. Within this domain, it is classified under the phylum Firmicutes. This phylum encompasses a large and diverse group of bacteria with varying morphologies and metabolic capabilities.
  • Class and Order: In the taxonomic hierarchy, L. acidophilus falls under the class Bacilli. This class is characterized by rod-shaped bacteria, a trait that L. acidophilus exhibits. Within this class, it is further classified under the order Lactobacillales. This order includes bacteria known for their ability to convert sugars into lactic acid.
  • Family and Genus: The family to which L. acidophilus belongs is Lactobacillaceae. This family is distinguished by its members’ primary metabolic product, lactic acid. The genus Lactobacillus, part of this family, is defined by the formation of lactic acid as the sole end product of carbohydrate metabolism.
  • Species: Within the genus Lactobacillus, the species is identified as L. acidophilus. This species is one of the most well-known and extensively studied within the genus, particularly for its probiotic properties and its presence in the human microbiota and various fermented foods.
  • Phylogenetic Analysis and Classification Criteria: The classification of L. acidophilus has been refined through phylogenetic analysis based on 16S rRNA sequences. This molecular approach has provided a more accurate classification compared to the earlier phenotypic and metabolic criteria. The species is a part of a larger group within the genus, often referred to as the L. acidophilus group, which is characterized by specific DNA-DNA homology and genomic GC content ranging from 32% to 50%.
  • Metabolic Classification: Lactobacillus species, including L. acidophilus, are further categorized based on their carbohydrate metabolism. These categories include obligately homofermentative, heterofermentative, and facultatively heterofermentative groups. L. acidophilus falls within one of these metabolic groups, which influences its role in various environments, including the human body and in fermented foods.

Habitat of Lactobacillus acidophilus

  • Natural Habitats and Carbohydrate Preference: Lactobacillus acidophilus predominantly inhabits environments rich in carbohydrates. This preference enables it to colonize a variety of natural habitats including plants, the mucosal surfaces of animals, and carbohydrate-rich foods. The high carbohydrate content in these environments provides the necessary nutrients for L. acidophilus to thrive.
  • Human Body Colonization: Within the human body, L. acidophilus is notably present in areas such as the mouth, gut, and vaginal cavity. These locations offer suitable conditions for the bacteria, primarily due to their natural carbohydrate availability. The presence of L. acidophilus in these areas plays a crucial role in maintaining the pH balance, creating an environment less hospitable to pathogenic organisms that cannot survive in such pH conditions.
  • Intestinal Colonization in Mammals: Besides human hosts, L. acidophilus is also found colonizing the intestines of various mammals, including pigs, cattle, mice, and rats. The bacteria’s adaptation to these environments highlights its versatility and the role it plays in the gastrointestinal health of different animal species.
  • Role in Vaginal Health: In the vaginal cavity, the colonization by L. acidophilus is observed to reduce the presence of Candida albicans, a common vaginal pathogen. This protective effect is assumed to be due to L. acidophilus occupying the mucosal surfaces, thereby preventing C. albicans from attaching and proliferating.
  • Occurrence in Food Products: Fermented milk products and beverages are typical habitats for L. acidophilus. In these food products, the presence of L. acidophilus can be either beneficial, enhancing desirable flavors, or detrimental, leading to food spoilage. The growth of L. acidophilus in milk products is primarily due to lactose, which serves as a carbohydrate source.
  • Silage and Agricultural Impact: L. acidophilus is also found in silage or hay used as feed for domestic animals. In this context, the bacteria contribute to the fermentation process, converting sugars present in grass into lactic acid, thereby preparing the silage for animal consumption.
  • Population Growth in Manure: Under certain conditions, L. acidophilus has been isolated from manure, where it demonstrates rapid population growth, doubling approximately every 20 minutes given suitable substrate and temperature conditions. This indicates the adaptability and resilience of L. acidophilus in various environmental conditions.

Morphology of Lactobacillus acidophilus

  • Metabolic Characteristics: Lactobacillus acidophilus is identified as a homofermentative anaerobic microorganism. This classification implies that it primarily produces lactic acid as the end product of its fermentation process. Specifically, L. acidophilus ferments hexoses (six-carbon sugars) via the Embden-Meyerhof-Parnas (EMP) pathway, also known as glycolysis.
  • Growth and Nutritional Requirements: The growth rate of L. acidophilus varies depending on the environment. In milk, its growth is slower compared to that in a host due to limited nutrient availability. Studies, including those published in the American Journal of Dairy Science, have revealed that L. acidophilus requires specific nutrients for optimal growth. Essential nutrients include glucose and several amino acids like cysteine, glutamic acid, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tyrosine, valine, and arginine. Additionally, glycine, calcium-pantothenate, and Mn2+ serve as stimulatory nutrients.
  • Cellular Morphology: L. acidophilus cells are characterized as large, non-sporing rods that are primarily Gram-positive. However, older cultures (over 48 hours) might exhibit Gram-negative characteristics. The size of these rod-shaped cells ranges from 0.6-0.9 × 1.5-6 µm. The cells’ length and degree of curvature depend on factors like the age of the culture, medium composition, and oxygen tension.
  • Cell Division and Arrangement: Division of L. acidophilus cells occurs along a single plane, often leading to chain formation, which varies among strains. This tendency is influenced by the growth phase and the pH of the medium. The cells, which have rounded ends, can be found individually, in pairs, or in short chains. In some cases, asymmetrical division results in wrinkled chains or, rarely, ring formations.
  • Flagella and Mobility: Depending on the culture medium and age, L. acidophilus may develop peritrichous flagella. These flagella are often observed during initial isolation but are typically lost after transfer to an artificial medium.
  • Cellular and Cytoplasmic Features: The cell wall of L. acidophilus is typical of Gram-positive bacteria, composed mainly of peptidoglycan of the Lys-D-Asp type. The cell membrane consists of a lipid bilayer with integrated protein units. This membrane’s fluidity can vary with environmental changes. Some strains may lack cell wall-bound teichoic acid, although membrane-bound teichoic acid is present. Within the cytoplasm, typical bacterial structures like ribosomes and nucleoids are present, along with large mesosomes formed by invaginations of the cytoplasmic membrane, often containing tubulin.

Metabolism of Lactobacillus acidophilus

  • Lactobacillus acidophilus is classified as a homofermentative anaerobic microorganism, which means it produces lactic acid as the sole end product of fermentation. It primarily utilizes the Embden-Meyerhof-Parnas (EMP) pathway, also known as glycolysis, to ferment hexoses and generate energy.
  • In its natural habitat, such as the human gastrointestinal tract, L. acidophilus has access to a diverse array of nutrients. However, when it is present in milk, its growth rate is slower due to limited nutrient availability. To address this issue and enhance its growth in milk, a study published in the American Journal of Dairy Science investigated the nutrient requirements of L. acidophilus.
  • The study revealed that certain nutrients are essential for the growth of L. acidophilus in milk. Glucose, along with specific amino acids including cysteine, glutamic acid, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tyrosine, valine, and arginine, were identified as crucial for its growth. Additionally, glycine, calcium-pantothenate, and Mn2+ were found to act as stimulatory nutrients, promoting the growth of L. acidophilus.
  • This research helps explain the relatively slow growth rate of L. acidophilus in milk, as certain amino acids necessary for its growth are limited in this medium. To overcome this limitation, one potential solution is to supplement fermented milk with amino acids that are highly consumed by L. acidophilus. This approach can support the growth and proliferation of the bacteria in milk, enhancing its viability as a probiotic.
  • In summary, Lactobacillus acidophilus is a homofermentative anaerobic microorganism that primarily produces lactic acid through the EMP pathway. Its growth rate in milk is slower due to the limited availability of essential nutrients. Understanding the specific nutrient requirements of L. acidophilus can help optimize its growth in milk-based products, potentially improving its viability as a probiotic.

Genomics of Lactobacillus acidophilus

  • The genomics of Lactobacillus acidophilus reveal interesting characteristics regarding its DNA replication, genome size, gene content, and metabolic capabilities. Replication in L. acidophilus initiates at the oriC origin and proceeds bidirectionally through replication forks. DNA synthesis occurs continuously on the leading strand and in discontinuous Okazaki fragments on the lagging strand, facilitated by the DNA polymerase III enzyme. The synthesis begins with an RNA primer and proceeds in the 5′ to 3′ direction.
  • L. acidophilus possesses a relatively small genome with a low guanine-cytosine (GC) content, approximately 30%. A comprehensive analysis of 46 L. acidophilus strains revealed a range of genome sizes from 1.95 Mb to 2.09 Mb, with an average size of 1.98 Mb. The average number of coding sequences within the genome was 1780, with strains isolated from fermented foods and commercial probiotics displaying a higher average number of coding sequences compared to those isolated from humans.
  • The pan-genome of L. acidophilus is considered open, meaning that the number of genes increases as more genomes are sequenced. However, the core-genome, which consists of genes shared by all individuals of the species, encompasses approximately 1117 genes in L. acidophilus. Notably, genetic analysis identified the presence of 15 families of glycosyl hydrolases in all L. acidophilus strains. These enzymes play a vital role in carbohydrate metabolism and are involved in metabolizing common carbohydrates such as glucose, galactose, fructose, sucrose, starch, and maltose.
  • Furthermore, L. acidophilus strains were found to harbor genes encoding antibiotic resistance mechanisms, including antibiotic efflux, antibiotic target alteration, and antibiotic target protection. This genetic repertoire provides protection against a broad range of antibiotics, encompassing 18 different classes. Among these classes, L. acidophilus demonstrated high tolerance to fluoroquinolones, glycopeptides, lincosamides, macrolides, and tetracyclines, with more than 300 relevant genes identified.
  • In summary, the genomics of Lactobacillus acidophilus shed light on its DNA replication process, genome size, gene content, and metabolic capabilities. Understanding these genomic characteristics enhances our knowledge of this bacterium’s genetic makeup and its potential applications in various fields, including food fermentation, probiotics, and antibiotic resistance.

Cultural Characteristics of Lactobacillus acidophilus

  • The cultural characteristics of Lactobacillus acidophilus can provide valuable information about its growth and appearance on different culture media.
  • Non-selective media such as MRS (de Man, Rogosa, and Sharpe) medium with a pH of 6.2 to 6.4 is commonly used for the isolation and cultivation of Lactobacillus species, including L. acidophilus. This medium supports the luxuriant growth of Lactobacillus from clinical samples.
  • Acetate medium (SL) is a selective medium specifically designed for the selective isolation of Lactobacillus. The presence of Tween 80 in this medium enhances the growth of L. acidophilus with a high acetate content at pH 5.4.
  • When cultured on appropriate media, L. acidophilus does not produce a characteristic odor. However, the presence of L. acidophilus in food can result in the production of numerous volatile compounds, which can either cause food spoilage or contribute to the desirable aroma of fermented food.
  • The optimal temperature for the growth of L. acidophilus is typically between 30°C and 42°C, with an optimum growth temperature of 35°C. It can survive a pH range of 5 to 7, with the optimum growth observed at a pH of 5.5.
  • L. acidophilus can exhibit different oxygen requirements depending on the strain. While most strains are aerobic and thrive under high oxygen tension, some strains, especially those isolated from food samples, are facultatively anaerobic and can grow well under reduced oxygen tension and increased CO2 levels.
  • Nutritional requirements of L. acidophilus include compounds such as calcium pantothenate, folic acid, niacin, and riboflavin, which are necessary for its growth and metabolism.
  • On solid culture media, L. acidophilus displays characteristic colony morphology. On Nutrient Agar (NA), colonies appear small, convex, smooth, and glistening, with an entire margin. They are opaque and do not exhibit pigmentation. Some strains may produce mucoid colonies due to the production of slime.
  • On MRS Agar, L. acidophilus forms slightly opalescent colonies that range from light to medium in color. Most strains produce opaque colonies that are convex, glistening, and smooth with an entire margin. However, some strains may produce rough colonies. L. acidophilus may also exhibit slight proteolytic activity, leading to clearing of the media due to the production of cell wall-bound and cell wall-released proteases.
  • When cultured on Blood Agar (BA), L. acidophilus forms small to medium grey-colored colonies that exhibit very weak β-hemolysis. The hemolysis produced by L. acidophilus is termed “bleaching” as it causes changes in the agar that resemble β-hemolysis, while the stromata of the blood cells remain intact.

Biochemical Characteristics of Lactobacillus acidophilus

The biochemical characteristics of Lactobacillus acidophilus can provide valuable information about its metabolic capabilities. Here are some of the key biochemical characteristics:

  1. Capsule: Non-Capsulated
  2. Shape: Rod
  3. Gram Staining: Gram-Positive
  4. Catalase: Negative (-)
  5. Oxidase: Negative (-)
  6. Citrate: Negative (-)
  7. Methyl Red (MR): Negative (-)
  8. Voges Proskauer (VR): Negative (+)
  9. OF (Oxidative-Fermentative): Oxidative
  10. Coagulase: Negative (-)
  11. DNase: Negative (-)
  12. Urease: Negative (-)
  13. Gas: Negative (-)
  14. H2S: Negative (-)
  15. Hemolysis: β-hemolytic
  16. Motility: Some strains are motile with single flagella
  17. Nitrate Reduction: Negative (-)
  18. Gelatin Hydrolysis: Negative (-)
  19. Pigment Production: Negative (-)
  20. Indole: Negative (-)
  21. TSIA (Triple Sugar Iron Agar): Alkali/Alkali (Red/Red)
  22. Spore: Non-sporing

Fermentation of Various Substrates:

  1. Amygdalin: Positive (+)
  2. Arabinose: Positive (+)
  3. Cellobiose: Positive (+)
  4. Dulcitol: Negative (-)
  5. Fructose: Positive (+)
  6. Galactose: Positive (+)
  7. Glucose: Positive (+) (Obligately homofermentative)
  8. Glycerol: Positive (+)
  9. Glycogen: Positive (+)
  10. Hippurate: Negative (-)
  11. Inulin: Negative (-)
  12. Inositol: Negative (-)
  13. Lactose: Positive (+)
  14. Malonate: Positive (+)
  15. Maltose: Positive (+)
  16. Mannitol: Negative (-)
  17. Mannose: Positive (+)
  18. Pyruvate: Negative (-)
  19. Raffinose: Positive (+)
  20. Rhamnose: Positive (+)
  21. Ribose: Negative (-)
  22. Salicin: Positive (+)
  23. Sorbitol: Negative (-)
  24. Starch: Positive (+)
  25. Sucrose: Positive (+)
  26. Trehalose: Negative (-)
  27. Xylose: Positive (+)

Enzymatic Reactions:

  1. Acetoin: Negative (-)
  2. Acetate Utilization: Positive (+)
  3. β-galactosidase: Positive (+)
  4. Esculin Hydrolysis: Positive (+)
  5. Casein Hydrolysis: Negative (-)
  6. Lactase: Positive (+)
  7. Lysine: Negative (-)
  8. Ornithine Decarboxylase: Positive (+)
  9. Phenylalanine Deaminase: Negative (-)

These biochemical characteristics help in the identification and differentiation of Lactobacillus acidophilus from other bacterial species.

Role of Lactobacillus acidophilus as Biopreservation resource

Lactobacillus acidophilus plays a significant role as a biopreservation resource due to its ability to compete against other microorganisms, including potential pathogens. It exhibits antimicrobial activity through various mechanisms, making it an effective natural preservative. Here are some of the key roles of L. acidophilus in biopreservation:

  1. Organic Acids: L. acidophilus produces organic acids such as lactic acid, acetic acid, and propionic acid during carbohydrate fermentation. These organic acids lower the pH of the environment, creating unfavorable conditions for the growth of pathogens and spoilage bacteria. They disrupt cell membrane integrity, inhibit active transport, and reduce intercellular pH, exerting antimicrobial effects against a broad range of bacteria.
  2. Flavor Compounds: L. acidophilus produces flavor compounds like diacetyl and acetaldehydes, which possess antimicrobial activity. Diacetyl, derived from citrate metabolism, contributes to the aroma and flavor of fermented milk products. Gram-negative bacteria and some yeasts are particularly sensitive to diacetyl and acetaldehyde.
  3. Hydrogen Peroxide: L. acidophilus produces hydrogen peroxide through different mechanisms in the presence of oxygen. Hydrogen peroxide acts as an antimicrobial agent by oxidizing sulfhydryl groups, denaturing enzymes, and peroxidizing membrane lipids. This antimicrobial action inhibits the growth of psychrotrophic and pathogenic microorganisms, even at refrigeration temperatures.
  4. Bacteriocins: L. acidophilus produces bacteriocins, which are proteinaceous substances with bactericidal activity against various microorganisms. Bacteriocins provide a competitive advantage to L. acidophilus in its ecological niche, inhibiting the growth of other microbes. They play a crucial role in the gastrointestinal tract, where L. acidophilus competes with potential pathogens. Bacteriocins are classified into four classes based on their structure and mode of action: Class I (lantibiotics), Class II (small heat-stable proteins), Class III (larger heat-labile proteins), and Class IV (complex substances with lipid and carbohydrate moieties). Examples of bacteriocins produced by L. acidophilus include Lactobacin B, lactacin F, acidocin A, and acidocin B, which exhibit activity against various pathogens.

By utilizing these antimicrobial mechanisms, Lactobacillus acidophilus acts as an effective biopreservative, inhibiting the growth of undesirable microorganisms and contributing to the preservation and safety of food products.

Role of Lactobacillusacidophilus in food and dairy industries

  • Lactobacillus acidophilus plays a significant role in the food and dairy industries, contributing to the production of various fermented products. In the dairy industry, L. acidophilus is employed in the production of acidophilus milk, yogurt, miru-miru, and kefir.
  • Acidophilus milk is specially formulated for individuals with lactase enzyme deficiency. The β-galactosidase enzyme produced by L. acidophilus hydrolyzes lactose in acidophilus milk, making it suitable for lactose-intolerant individuals. The addition of L. acidophilus as a starter culture in milk fermentation contributes to flavor development and texture enhancement through the action of proteolytic enzymes. By converting lactose into lactic acid, L. acidophilus lowers the pH of the milk, leading to its coagulation.
  • In the production of cheese, the flavor development process depends on both starter and non-starter Lactobacillus species. L. acidophilus aids in the faster ripening of cheeses like cheddar, reducing the occurrence of bitterness. Yogurt, on the other hand, owes its distinctive flavor to the synergistic action of Streptococcus thermophilus and Lactobacillus species, including L. acidophilus. During milk fermentation, L. acidophilus produces various flavor compounds such as organic acids (acetic acid, propanoic acid) and other compounds like diacetyl, acetaldehyde, and acetoin.
  • Texture in yogurt is influenced by the production of exopolysaccharides by L. acidophilus, which act as viscosifying agents. Coagulation, facilitated by L. acidophilus, further enhances the texture by neutralizing the negative charges present in the milk. Additionally, L. acidophilus is present in powdered milk, extending its shelf life and imparting biopreservation properties.
  • Lactobacillus acidophilus is not limited to dairy products; it also participates in the fermentation of other food items. These include soymilk, soy-based yogurt, kombucha, fermented vegetable juice, kimchi, sausages, and salami. Its presence in these products contributes to their unique flavors and characteristics.
  • In summary, Lactobacillus acidophilus plays a vital role in the food and dairy industries, contributing to the production of fermented milk products, enhancing flavor and texture, and extending the shelf life of certain products. Its versatility extends beyond dairy, as it contributes to the fermentation of various foods, enriching their flavors and qualities.

Role of Lactobacillus acidophilus in human health

  • Lactobacillus acidophilus plays a significant role in promoting human health as a probiotic. Numerous studies have highlighted its potential health benefits, which include alleviating gastrointestinal symptoms in lactose-intolerant individuals, providing relief from constipation, aiding in the treatment of infantile diarrhea, and exhibiting activity against Helicobacter pylori.
  • In individuals with lactose intolerance, L. acidophilus plays a crucial role as it possesses β-galactosidase, an enzyme that degrades lactose, thus enabling better digestion and reducing gastrointestinal discomfort. Moreover, L. acidophilus has been shown to contribute to the prevention of gastric inflammation caused by H. pylori infections.
  • However, it is worth noting that while L. acidophilus offers multiple health benefits, there have been rare instances of infections associated with this bacterium. These infections, although uncommon and typically not food-borne, may occur in immunocompromised individuals, where L. acidophilus can act as an opportunistic pathogen. Infections linked to L. acidophilus include lactobacillemia, which, under severe conditions, can lead to endocarditis and bacteremia.
  • The exact mechanisms underlying L. acidophilus-associated infections are not fully understood, but potential indicators of pathogenicity include enzymatic activity, bacterial translocation, mucin degradation, and platelet aggregation. It is important to consider the colonization and adherence of L. acidophilus to host tissues in both probiotic applications and infection cases. Some strains of L. acidophilus have been found to possess amino acid decarboxylase activity, leading to the production of biogenic amines, which can have harmful effects on the host. The production of various proteases by L. acidophilus also supports colonization and dissemination through host tissues, potentially contributing to conditions like endocarditis.
  • Nevertheless, it is crucial to emphasize that L. acidophilus-associated infections are extremely rare based on epidemiological studies, and they generally occur in individuals with specific pre-existing conditions. The overall positive impact of L. acidophilus on human health is evident, particularly when used as a probiotic.
  • As a probiotic, L. acidophilus can contribute to the maintenance of a healthy gut microbiota, supporting digestion, nutrient absorption, and immune function. It helps restore the balance of beneficial bacteria in the gut and may enhance overall gastrointestinal well-being. The specific strains of L. acidophilus utilized as probiotics are carefully selected for their ability to survive the harsh conditions of the gastrointestinal tract and exert beneficial effects on the host.
  • In summary, Lactobacillus acidophilus has shown promise as a probiotic with various health benefits. While rare instances of infections have been reported, the overall positive impact of L. acidophilus on human health outweighs the potential risks, especially when used under appropriate conditions and in individuals without specific predispositions.

Probiotic Lactobacillus acidophilus

  • Lactobacillus acidophilus, a probiotic microorganism, has gained recognition for its potential health benefits. Probiotics are living microorganisms that, when administered in appropriate amounts, provide a health benefit to the host. While the significance of healthy gut microorganisms in preventing gastrointestinal infections has long been studied, the use of probiotics as preventive and therapeutic agents has gained momentum in recent years.
  • The selection of L. acidophilus as a probiotic is based on specific criteria. It must have the ability to survive the journey through the upper gastrointestinal tract and reach the desired site of action. Additionally, it should demonstrate tolerance to human gastric juice and possess antagonistic properties against intestinal pathogens. L. acidophilus meets these criteria and stands out as a promising probiotic candidate.
  • One of the key characteristics of L. acidophilus is its ability to stabilize and modulate the intestinal microbiota. By promoting the growth of beneficial microorganisms, L. acidophilus contributes to a healthy balance within the gut. Furthermore, L. acidophilus has been found to establish strong adherence to epithelial cells, allowing it to exert its beneficial effects more effectively.
  • L. acidophilus is commonly found in various dairy products, making them convenient carriers for delivering probiotics to the human body. These products include pasteurized milk, ice cream, cheeses, and fermented milk. Yogurt, a classic probiotic fermented product, has been consumed for many years due to its association with digestive health benefits. Cheese, with its low oxygen levels and high lipid content, also serves as a suitable carrier for live probiotic bacteria, including L. acidophilus.
  • As research in the field of probiotics advances, the potential health benefits of Lactobacillus acidophilus and other probiotic strains are being further explored. These beneficial microorganisms have the ability to support the overall well-being of individuals by promoting a balanced gut microbiota and aiding in various aspects of digestive health.
  • In conclusion, Lactobacillus acidophilus is a probiotic with significant potential. Its ability to survive the gastrointestinal tract, tolerance to gastric conditions, and antagonistic activity against pathogens make it an ideal candidate for promoting gut health. Incorporating L. acidophilus into dairy products provides a convenient and effective means of delivering these beneficial microorganisms to consumers. As our understanding of probiotics continues to expand, the role of L. acidophilus in supporting human health is likely to gain further recognition.

Benefits of L. acidophilus probiotics

Lactobacillus acidophilus probiotics offer numerous benefits to human health. Here are some notable advantages:

  • Digestive benefits: L. acidophilus aids in the metabolism and breakdown of lactose, providing relief from lactose intolerance symptoms such as intestinal pain, diarrhea, gas, and bloating. It promotes the flourishing of essential gut microbiota by releasing growth factors, thereby facilitating proper digestion. The use of L. acidophilus probiotics has also shown promise in alleviating symptoms associated with irritable bowel syndrome, including diarrhea, constipation, and bloating. The bacteria’s production of bacteriocins and metabolic products contributes to its antagonistic activity against intestinal pathogens.
  • Immunity: L. acidophilus probiotics have immune-boosting properties. By maintaining the population of normal microbiota and producing various compounds with antagonistic activity, they support a robust immune system. Additionally, L. acidophilus helps reduce inflammation in different parts of the body, particularly in the digestive tract. Its ability to prevent infections caused by Helicobacter pylori, a common digestive system pathogen, further highlights its immune-protective effects. The preservation action of L. acidophilus, achieved through the production of metabolic products, aids in preventing colonization by pathogenic bacteria.
  • Other benefits: L. acidophilus probiotics play a role in the prevention and treatment of vaginal yeast infections. When used alongside necessary antibiotics, the infections can be resolved within a few days rather than weeks. These bacteria also contribute to improving the digestive tract microbiota in non-breast-fed infants. Research suggests that probiotics, such as L. acidophilus, may exhibit anti-tumor activity due to their high-density lipoprotein content. Furthermore, L. acidophilus probiotics have shown potential in reducing symptoms of atopic dermatitis, a common form of eczema.

Overall, Lactobacillus acidophilus probiotics offer a range of health benefits. Their positive impact on digestive health, immune system support, and potential effects on various conditions make them a valuable addition to promoting overall well-being. As further research is conducted, the full potential of L. acidophilus probiotics in enhancing human health is likely to be unveiled.

Side effects of Lactobacillus acidophilus probiotics

  • While Lactobacillus acidophilus probiotics are generally considered safe, there are a few minimal side effects associated with their intake. It’s important to note that these side effects are generally mild and temporary.
  • One common side effect is the occurrence of gas, bloating, and other mild digestive complaints. This is often attributed to the changes in the gut microbiota as the probiotics establish themselves.
  • In some cases, individuals may experience rashes or acne, particularly if they have underlying immune conditions. Probiotics have the potential to induce inflammation, which can manifest as skin-related issues.
  • It’s important to emphasize that these side effects are typically short-lived and should resolve within 12-14 days. If, however, severe or persistent effects are observed, it is recommended to discontinue the use of probiotics and seek immediate medical assistance.
  • It’s worth noting that adverse reactions to L. acidophilus probiotics are rare, and the majority of individuals tolerate them well. As with any dietary supplement, it is advisable to consult with a healthcare professional before starting probiotic supplementation, especially for individuals with specific health conditions or compromised immune systems.
  • Overall, while side effects from L. acidophilus probiotics are generally minimal, it’s important to be aware of any changes or reactions and seek medical guidance if needed.


What is Lactobacillus acidophilus?

Lactobacillus acidophilus is a species of beneficial bacteria commonly found in the human body, particularly in the gastrointestinal tract, mouth, and vaginal cavity. It is considered a probiotic, which means it provides health benefits when consumed in adequate amounts.

What are the potential health benefits of Lactobacillus acidophilus?

Lactobacillus acidophilus has been associated with various health benefits, including improved digestion, relief from lactose intolerance symptoms, prevention of vaginal infections, enhanced immune function, and potential anti-inflammatory effects. However, individual responses may vary.

How can I consume Lactobacillus acidophilus?

Lactobacillus acidophilus is commonly consumed in the form of probiotic supplements, yogurt, fermented milk products, and certain dairy foods. It is important to follow the recommended dosage and instructions provided by the manufacturer or healthcare professional.

Can Lactobacillus acidophilus help with digestive problems?

Lactobacillus acidophilus has been studied for its potential to alleviate digestive issues such as lactose intolerance, irritable bowel syndrome (IBS), and diarrhea. However, it is important to consult with a healthcare professional before using probiotics for specific digestive concerns.

Are there any side effects of Lactobacillus acidophilus?

In general, Lactobacillus acidophilus is considered safe for most individuals. However, some people may experience mild side effects such as gas, bloating, or temporary digestive discomfort. If you experience severe or persistent symptoms, discontinue use and consult a healthcare professional.

Can Lactobacillus acidophilus be used during pregnancy or breastfeeding?

While Lactobacillus acidophilus is generally considered safe for pregnant or breastfeeding women, it is recommended to consult with a healthcare professional before using any supplements or probiotics during these periods.

Can Lactobacillus acidophilus be taken with antibiotics?

Yes, Lactobacillus acidophilus can be taken alongside antibiotics. Antibiotics can disrupt the natural balance of bacteria in the gut, and probiotics like Lactobacillus acidophilus may help replenish beneficial bacteria. However, it is advisable to separate the timing of antibiotic and probiotic intake to maximize their effectiveness. Consult with a healthcare professional for personalized guidance.

Is Lactobacillus acidophilus suitable for children?

Lactobacillus acidophilus is generally safe for children. However, it is advisable to consult with a pediatrician before administering probiotics to children, especially in specific health conditions or when using supplements.

How long does it take for Lactobacillus acidophilus to work?

The time it takes to experience the benefits of Lactobacillus acidophilus can vary depending on individual factors, the specific health concern, and the dosage used. It is important to be consistent with the recommended dosage and allow sufficient time for the probiotics to establish in the gut.

Can I take Lactobacillus acidophilus if I have a weakened immune system?

Individuals with compromised immune systems should consult with a healthcare professional before taking any supplements, including Lactobacillus acidophilus. While probiotics are generally safe, it is essential to ensure they are appropriate for your specific health condition and medical history.


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What is a digital colony counter? Why do Laboratory incubators need CO2? What is Karyotyping? What are the scope of Microbiology? What is DNA Library? What is Simple Staining? What is Negative Staining? What is Western Blot? What are Transgenic Plants? Breakthrough Discovery: Crystal Cells in Fruit Flies Key to Oxygen Transport
What is a digital colony counter? Why do Laboratory incubators need CO2? What is Karyotyping? What are the scope of Microbiology? What is DNA Library? What is Simple Staining? What is Negative Staining? What is Western Blot? What are Transgenic Plants? Breakthrough Discovery: Crystal Cells in Fruit Flies Key to Oxygen Transport
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