Biodetoxification and Protective Properties of Probiotics

Probiotic consumption is recognized as being generally safe and correlates with multiple and valuable health benefits. However, the mechanism by which it helps detoxify the body and its anti-carcinogenic and antimutagenic potential is less discussed. A widely known fact is that globalization and mass food production/cultivation make it impossible to keep all possible risks under control. Scientists associate the multitude of diseases in the days when we live with these risks that threaten the population’s safety in terms of food. This review aims to explore whether the use of probiotics may be a safe, economically viable, and versatile tool in biodetoxification despite the numerous risks associated with food and the limited possibility to evaluate the contaminants. Based on scientific data, this paper focuses on the aspects mentioned above and demonstrates the probiotics’ possible risks, as well as their anti-carcinogenic and antimutagenic potential. After reviewing the probiotic capacity to react with pathogens, fungi infection, mycotoxins, acrylamide toxicity, benzopyrene, and heavy metals, we can conclude that the specific probiotic strain and probiotic combinations bring significant health outcomes. Furthermore, the biodetoxification maximization process can be performed using probiotic-bioactive compound association.


Introduction
Food is vital for human health, delivering energy, and nutrients, and plays crucial roles in the human body, tissues, growth and development of organs, normal function, and metabolism [1,2]. Besides nutrients, food could have traces of different toxins (as naturally occurring or by-products during food processing or storage), usually at non-detectable levels and below unobserved adverse effect levels. Food toxins, including fungi (yeasts and molds), industrial waste contaminants-heavy metals (arsenic (As), cadmium (Cd), mercury (Hg), and lead (Pb)), acrylamide, and benzopyrene, increase the risk of dysbiosis, mutagenesis, and carcinogenesis [3][4][5]. Food and feed contamination are almost impossible to entirely avoid. Instead, the adoption of various measures to detoxify contaminated food and feed is more feasible and necessary. Several techniques (physical, chemical, and biological) have been studied to detoxify and mitigate hazards affecting the population's health and significantly diminish the economic damage caused by these toxins in food and feed. These methods act by destroying or modifying the toxin's molecular structure, resulting in the toxin's low accessibility to the digestive system [1,3,4,6].
The toxic chemical biodetoxification could be associated with the gut microbiota, which is essential for maintaining intestinal integrity in the longer term. Overall, the gut tract's microbiota might also be crucial for in vivo biodetoxification. In the past decades, probiotics have raised interest due to their comprehensive properties, not only in the digestive system but also in vivo biodetoxification [7][8][9]. This review aims to demonstrate Microorganisms 2022, 10, 1278 3 of 20 (ii) increase mucosal immunity-increasing IgA-producing cells; and (iii) reduce pathogens numbers and/or their gene expression [15,30].
In their study, Barouei et al. show how mucin secretion, is sustained by downregulation of plasma IFN-γ and haptoglobin in the presence of B. animalis subsp. lactis BB-12 and Propionibacterium jensenii 702 in concentration of 3 × 10 9 and 8.0 × 10 8 CFU/mL respectively [31]. Yang et al. 2012 demonstrate the protective effect of yogurt probiotics (L. acidophilus, B. lactis, L. bulgaricus, and Streptococcus thermophilus) in Helicobacter pylori infection by restoring affected Bifidobacterium in the gut microflora and by increasing serum IgA titer (low in H. pillory infection) [32].
In most cases, the protective effect of probiotics, in various pathologies, is based on multiple ways of action.

Probiotic Safety Issues
It is widely accepted that the most used probiotic strains are safe for usage [16,21]. These strains received the status "qualified presumption of safety." The safety assessment should include the type of microorganism being used, the method of administration, the exposure levels, and the consumer's health status. While probiotics are commonly acknowledged as safe for healthy subjects, few pieces of evidence emphasize the contrary for certain groups with unique risks [33]. Nevertheless, the potential benefits of probiotics compensate for the potential risks when considering the long-term. Probiotic species may have a natural origin or could be genetically engineered (tailored probiotics) for a specific effect (i.e., expressing a specific protein, biomaterial delivery, annihilating infectious pathogens to combat infectious, and metabolic diseases), so their impact on human health may differ, or their mechanisms of action may vary [34]. The FAO research group reports that probiotic action in patients with special medical status could be associated with four specific forms of side effects and risks ( Figure 1): "(1) systemic infections; (2) deleterious metabolic activities; (3) excessive immune stimulation in susceptible individuals; and (4) gene transfer" [35].
Microorganisms 2022, 10, x FOR PEER REVIEW 3 of 21 increase mucosal immunity-increasing IgA-producing cells; and (iii) reduce pathogens numbers and/or their gene expression [15,30]. In their study, Barouei et al. show how mucin secretion, is sustained by down-regulation of plasma IFN-γ and haptoglobin in the presence of B. animalis subsp. lactis BB- 12 and Propionibacterium jensenii 702 in concentration of 3 × 10 9 and 8.0 × 10 8 CFU/mL respectively [31]. Yang et al. 2012 demonstrate the protective effect of yogurt probiotics (L. acidophilus, B. lactis, L. bulgaricus, and Streptococcus thermophilus) in Helicobacter pylori infection by restoring affected Bifidobacterium in the gut microflora and by increasing serum IgA titer (low in H. pillory infection) [32].
In most cases, the protective effect of probiotics, in various pathologies, is based on multiple ways of action.

Probiotic Safety Issues
It is widely accepted that the most used probiotic strains are safe for usage [16,21]. These strains received the status "qualified presumption of safety." The safety assessment should include the type of microorganism being used, the method of administration, the exposure levels, and the consumer's health status. While probiotics are commonly acknowledged as safe for healthy subjects, few pieces of evidence emphasize the contrary for certain groups with unique risks [33]. Nevertheless, the potential benefits of probiotics compensate for the potential risks when considering the long-term. Probiotic species may have a natural origin or could be genetically engineered (tailored probiotics) for a specific effect (i.e., expressing a specific protein, biomaterial delivery, annihilating infectious pathogens to combat infectious, and metabolic diseases), so their impact on human health may differ, or their mechanisms of action may vary [34]. The FAO research group reports that probiotic action in patients with special medical status could be associated with four specific forms of side effects and risks (  Probiotic functional foods or supplements may contain a single or mix of bacteria species on the market. Several products containing probiotics, including milk, infant formula, cheese, drinks, and dietary supplements, are marketed in classical or novel procedures worldwide. This aspect results in the large ingestion of probiotic cells and significant interaction with various gut microbes at high densities. Thus, any gene resistant to antibiotics carried by probiotic cells may be relocated to the gut microorganisms, including pathogens [36]. Therefore, we should consider the risk of ingesting antibiotic resistance genes or antibiotic-resistant bacteria.
The genes in Bacillus probiotics indicate a potential health risk due to the production of their toxins, and they harbor various antimicrobial resistance genes [37].
Probiotics could have adverse effects if used inappropriately or if they do not meet the required standards [38]. Indeed, their application in preventing, ameliorating, or Probiotic functional foods or supplements may contain a single or mix of bacteria species on the market. Several products containing probiotics, including milk, infant formula, cheese, drinks, and dietary supplements, are marketed in classical or novel procedures worldwide. This aspect results in the large ingestion of probiotic cells and significant interaction with various gut microbes at high densities. Thus, any gene resistant to antibiotics carried by probiotic cells may be relocated to the gut microorganisms, including pathogens [36]. Therefore, we should consider the risk of ingesting antibiotic resistance genes or antibiotic-resistant bacteria.
The genes in Bacillus probiotics indicate a potential health risk due to the production of their toxins, and they harbor various antimicrobial resistance genes [37].
Probiotics could have adverse effects if used inappropriately or if they do not meet the required standards [38]. Indeed, their application in preventing, ameliorating, or treating some diseases is essential, but knowing and facing the other side is crucial. In specific cases, probiotics and probiotic mixt administration in high-risk populations may result in health complications [39]. Therefore, we conclude that probiotic supplements can be effective in different age groups of consumers and should be wisely selected. Furthermore, it is prudent to take precautions when administering probiotics.

Food Contaminants and Their Impact on Human Health
In specific cases, food can be hazardous to one's health, causing disease and death. Approximately two million people die annually, including children, due to contaminated foods full of harmful chemicals (heavy metals, acrylamide, polycyclic aromatic hydrocarbonbenzopyrene) or biological (microorganisms, pathogens, fungi-molds, and yeasts) compounds [40,41].
Everything we eat that is not harmful to animals and humans is labeled "safe food". An organization in every country is responsible for food safety, regulating additives and their concentrations permitted in food [41]. Toxic compounds may be naturally occurring or by-products resulting from processing, storage, or cooking [42]. It is difficult to test for intoxications because most foods cannot be tested for every possible toxic compound. To accurately detect unknown and known contaminants, it is necessary to run several follow-up cases of intoxication [40]. Currently, the authorities need to be more concerned about food safety because globalization, easy traveling, and rapid food habits are changing. The illnesses caused by pathogens, toxins, and other contaminations in the food ( Figure 2) cause a real health risk to humans and animals. Analyses and control measures mean a significant budget loss for the food industry [41]. treating some diseases is essential, but knowing and facing the other side is crucial. In specific cases, probiotics and probiotic mixt administration in high-risk populations may result in health complications [39]. Therefore, we conclude that probiotic supplements can be effective in different age groups of consumers and should be wisely selected. Furthermore, it is prudent to take precautions when administering probiotics.

Food Contaminants and Their Impact on Human Health
In specific cases, food can be hazardous to one's health, causing disease and death. Approximately two million people die annually, including children, due to contaminated foods full of harmful chemicals (heavy metals, acrylamide, polycyclic aromatic hydrocarbon-benzopyrene) or biological (microorganisms, pathogens, fungi-molds, and yeasts) compounds [40,41].
Everything we eat that is not harmful to animals and humans is labeled "safe food". An organization in every country is responsible for food safety, regulating additives and their concentrations permitted in food [41]. Toxic compounds may be naturally occurring or by-products resulting from processing, storage, or cooking [42]. It is difficult to test for intoxications because most foods cannot be tested for every possible toxic compound. To accurately detect unknown and known contaminants, it is necessary to run several followup cases of intoxication [40]. Currently, the authorities need to be more concerned about food safety because globalization, easy traveling, and rapid food habits are changing. The illnesses caused by pathogens, toxins, and other contaminations in the food ( Figure 2) cause a real health risk to humans and animals. Analyses and control measures mean a significant budget loss for the food industry [41]. A constant preoccupation of the food safety authorities is the exposure levels of the population or specific group of people, resulting in regulations that assess the maximum level of exposure allowed. Several studies discuss the toxicokinetic and toxicodynamics interaction of toxic compounds with the human body [43]. These studies reveal various detoxification strategies for reducing, annihilating, or converting toxic compounds. These strategies can be classified into physical (peeling, heat, ultraviolet light, ionizing radiation, and solution absorption), chemical (chlorination, oxidant, and hydrolytic substances utilization), and biological (inside the body or in food products using enzymes or probiotics). Because physical and chemical methods have some disadvantages associated with nutritional degradation, inefficiency for some toxins, secondary contaminants, and consumers' acceptance and concerns, as well as a need to reduce and replace chemical technology with high sensitivity, specificity, and environment-friendly methods, biodetoxification using probiotics is proposed [6,44]. A constant preoccupation of the food safety authorities is the exposure levels of the population or specific group of people, resulting in regulations that assess the maximum level of exposure allowed. Several studies discuss the toxicokinetic and toxicodynamics interaction of toxic compounds with the human body [43]. These studies reveal various detoxification strategies for reducing, annihilating, or converting toxic compounds. These strategies can be classified into physical (peeling, heat, ultraviolet light, ionizing radiation, and solution absorption), chemical (chlorination, oxidant, and hydrolytic substances utilization), and biological (inside the body or in food products using enzymes or probiotics). Because physical and chemical methods have some disadvantages associated with nutritional degradation, inefficiency for some toxins, secondary contaminants, and consumers' acceptance and concerns, as well as a need to reduce and replace chemical technology with high sensitivity, specificity, and environment-friendly methods, biodetoxification using probiotics is proposed [6,44].

Heavy Metals
Human daily activities release heavy metals into the soil, air, and water. The most studied and known damage produced by heavy metals is the induced oxidative stress, resulting in cellular damage. Each heavy metal has its free radical generation mechanism targeting proteins involved in the apoptosis, cell cycle regulation, growth and differentiation, DNA methylation, and DNA repair-materializing in carcinogenesis. Some heavy metals may have neurotoxic impact induced by mechanisms, such as reducing neurotransmitters or accumulating mitochondria of neurons that disrupts adenosine triphosphate (ATP) synthesis [6,45].
Overwhelming metal contamination is a critical issue within the food industry, which undermines human health. The most common heavy metal contaminants are arsenic (As), cadmium (Cd), copper (Cu), mercury (Hg), nickel (Ni), lead (Pb), and zinc (Zn) [41]. Heavy metals entering the body increase the risk of developing cardiovascular, kidney, and neurological diseases [6,45]. A more toxic form of Hg is methylmercury, a strong neurotoxin, which affects the human central nervous system [46]. Pb is mutagenic and teratogenic, and it can negatively affect the neurotic system, interfering with the synthesis of hemoglobin, damaging kidney functionality, and reducing semen quality [47]. Cd can cause various diseases, such as cardiovascular, liver, reproductive system disorders, osteomalacia, and lung and renal cancer [48].
Among the detection methods for heavy metals, the most utilized are atomic absorption spectrometry, atomic fluorescence spectrometry, or spectrophotometry; lately, due to a demand for real-time detection, electrochemical biosensors have been used in this sense [6]. Bacterial biomass can also remove heavy metals from aqueous solutions [46].

Acrylamide
Foods subjected to heat treatments (roasting and baking) undergo several unwanted changes, such as lipid oxidation, protein denaturation, vitamin degradation, and the formation of compounds harmful to the human body [49].
Acrylamide is mainly found in carbohydrate-rich bakery products (bread, biscuits, cookies, and baby foods based on cereals), french fries, chips, coffee, and meat preparations, subjected to high heat treatments. Small quantities of acrylamide, almost undetectable, can also be found in packaged foodstuffs due to its migration from the materials used in packaging that directly contact the product [49,50]. It is formed due to reactions between asparagine and reducing sugars (glucose, glyoxal, glycerol, and 2-deoxyglucose) [51]. The most conclusive detection method is mass spectrometry combined with capillary electrophoresis, gas, or liquid chromatography, especially high-performance liquid chromatography [50].
After ingestion, the human and animal bodies absorb and accumulate it in various organs, such as the heart, brain, liver, thymus, kidneys, muscle tissue, skin, and testes. The main pathway of acrylamide metabolism involves conversion to glycidamide and its conjugation to glutathione [49,50].
Studies have shown that acrylamide can cause genetic and reproductive toxicity, neurotoxicity, carcinogenicity, oxidative stress, and changes in genetic material (Khorshidian et al., 2020). When ingested doses are higher than recommended (100 mg/kg), it can cause acute toxic effects and lethal effects when it exceeds 150 mg/kg [49]. Probiotic capacity to reduce the damage produced by acrylamide ingestion is associated with their antioxidant activity [52].

Polycyclic Aromatic Hydrocarbons-Benzo[a]Pyrene
The primary source of polycyclic aromatic hydrocarbons (PAHs) is the incomplete combustion of the material's body, such as coal, oil, and wood. PAHs are toxic to aquatic life, birds, and soil. They are absorbed by mammals through various methods (inhalation) and by plants through roots, which afterward translocate them to other parts of the plant. The most toxic member of the environmental pollutant PAHs family is Benzo[a]pyrene (B[a]P). B[a]P absorptions have pro-inflammatory effects and can induce tumors (gastrointestinal, bladder, and lung cancers), reproduction disorders, mutagenesis, disturbing development, and immunity deficiency [53][54][55].
Studies established that contamination with B[a]P is inevitable, which is caused by polluted water, soil exposure, and food consumption. Due to its low water solubility, B[a]P is recalcitrant to microbial degradation [54].

Fungi-Molds and Yeasts and Their Mycotoxins
Probiotics are studied to improve food security and human health by inhibitory action on fungi-yeasts and molds. Around 5-10% of the world's food system is affected because of fungal impairment causing carcinogenesis through the produced mycotoxins. As a result, many acids, including acetic, propionic, sorbic, lactic, and benzoic are used in food preservation. Concerns are raised because yeasts and molds developed a resistance to antibiotics, preservatives, and sanitizer agents, demanding a better alternative [56][57][58]. Among contaminants, mycotoxins are probably the biggest threat to human health due to their high carcinogenesis. In addition, mycotoxins formed by certain kinds of fungi can cause acute poisoning and a significant deficit in the immune system [59,60].
The interaction between mycotoxins and probiotic cells is influenced by the cellular wall's integrity, which is responsible for the absorption capacity [61].

Biodetoxification Activity of Probiotics
Producers, authorities, and consumers face food safety-related challenges. The population is exposed to fungus, mycotoxin and virus infections, chemicals (acrylamide, benzopyrene, heavy metals), mutagenic and carcinogenic compounds. The need for viable, generally accepted, and applicable detoxification methods are sustained not necessarily by economic damage but by the danger to human well-being in general [37,41].
Biodetoxification may be an intrinsic phenomenon, mainly in the enzymatic system and human microbiota, but it can also be an external, controlled, and directed phenomenon that ensures food safety before the contaminated food product is ingested [4].
Probiotics can bind mutagens and carcinogens, such as aflatoxins [4]. Further, we will discuss how the most commonly used probiotic genera reported as being able to biodegrade, absorb, or induce physical adhesion to different toxic compounds or pathogen microorganisms are frequently incriminated for foodborne diseases.

Lactobacillus (LAB) Genera and Their Biodetoxification Capacity
Lactobacillus genera are the most known and used probiotic [16,53]. For the conversion of glucose to lactic acid, Gram-positive and non-spore-forming bacteria, such as Lactic Acid Bacteria (LAB), can be used to initiate lactic acid fermentation [16]. During fermentation, lactose to lactate conversion reduces the danger of carcinogenic and mutagenic chemicals [62]. LAB can also remove pollutants from food through various metabolic activities, according to recent research (Table 1). Fermentation, antibiosis, and the capacity of the microbial cell wall to attach to the toxin are factors in these microorganisms' decontaminant action [57]. The antimicrobial qualities of LAB can effectively limit the growth of other pathogenic microorganisms and fungi [54]. Yeast and lactic acid bacteria (LAB) mycotoxin involve fighting binding aflatoxins [63].
LAB reduces AFM1 (aflatoxin M1) and potentially decreases toxins in yogurt to a safe concentration for consumption (below 0.05 µg/kg). Research proved the capacity of L. acidophilus to bind AB1 and AM1 in cow's milk [64]. A simulated gastrointestinal model sustained these results by proving the ability of L. acidophilus and L. casei (~10 log CFU/mL) to bind with AFB1 (aflatoxin B1); however, in contrast, it also underlined a reduced binding capacity in the presence of milk. The authors of the study concluded that micronutrients present in milk have a protective effect on the micotoxin (covering effect) [65]. Another study revealed that L. kefiri FR7 can reduce Aspergillus flavus and A. carbonarius growth and their mycotoxin production capacity [57].
Wu and his colleagues examined the prevention of colorectal carcinoma induced by B[a]P. They administered to mice, with colorectal-induced tumorigenesis, polymethoxiflavone (PMF), an anticancer agent found in citrus peels. The result indicated that by the oral administration of PMF, B[a]P-induced colon tumorigenesis (Benzo[a]pyrene) was blocked [66]. A practical explanation is gut microbiota modulation by prebiotic-like compounds.
In 2021, a group of researchers proved that L. acidophilus NCFM (1 × 10 10 CFU/mL), among five bacterial strains (L. plantarum 121, Leuconostoc mesenteroides DM1-2, L. acidophilus NCFM, L. paralimentarius 412, and L. pentosus ML32), has the best capacity to bind B[a]P, the pH being (optimal pH 6) the parameter that influenced its binding yield the most, among incubation time, temperature, and strain concentration, [53]. Madreseh et al. proved that L. fermentum 1744 (ATCC 14931) (1 × 10 9 CFU/mL) may significantly reduce heavy metal (Pb, Zn, Ni, and Cd) absorption and accumulation in living organisms (rainbow trout). The best results were obtained for the encapsulated probiotics in the presence of lactulose (10 g/kg feed) [45]. The probiotic's ability to reduce heavy metals as well as the toxic effects of heavy metals in vitro and in vivo is related to its mechanism's binding ability due to the numerous negatively charged functional groups found in the probiotics cell wall [67], the modulation of different over-expressed genes upon exposure to heavy metals [6], and an enhancement in the fecal excretion of ingested heavy metals [68].  To sum up, the two hypotheses are attributed to the probiotic detoxification action. The first mechanism consists of the physical connection between the probiotic and contaminant. The second is when probiotics and strains can mitigate the carcinogenic danger through their metabolism. The cell wall of probiotics is primarily composed of peptidoglycan found in glycan chains consisting of alternating N-needles tilglucosamine and N-2 acetylmuramic acid, linked by β-1,4 bond [74].
Factors affecting contaminants' LAB bindings are associated with the proper selection of strains with a high capacity to eliminate the food contaminant [53,54,69]. We can state that the growth phase, incubation time, pH, contaminant concentration, and characteristics significantly affect probiotics' binding/antimicrobial properties, but the binding ability may be related to the dose [54,[75][76][77]. All studies showed that the detoxification rate is influenced by the contaminant and probiotic cell concentration, exposure time, pH, temperature, and nutrient presence [4,65,78,79].

Bifidobacteria Genera and Their Biodetoxification Capacity
The genus Bifidobacterium includes Gram-positive, non-motile, non-spore, Y-or Vshaped, anaerobic bacteria that produce lactic and acetic acids without producing CO 2 . Bifidobacterium growing temperature is around 36 • C and 38 • C, with optimum pH values ranging from 6.5 to 7. Amino acids, thiamin, and riboflavin can all be synthesized by Bifidobacterium [80,81]. Antibiotic resistance is a feature of select LAB, which has been widely employed to manufacture probiotic-fermented foods, called preparations. Shortchain fatty acids (SCFAs) interact with the host cell and gut microbiota as significant products of substrate fermentation in the gut [16]. The pH of the gut is lowered by these two acids, notably in the cecum and ascending colon. Many dangerous bacteria are suppressed in a low-pH environment; hence Bifidobacterium's capacity to raise the acidity of the gut likely plays a role in its probiotic benefits [81]. Studies have indicated the binding or physical absorption of toxins by Bifidobacterium [42,55,70] (Table 2). A research paper discovered that having B. lactis HN019 in the diet can boost natural immunity. In macrophage cell lines, live or heat-killed Bifidobacterium and Lactobacillus species and certain of their cellular constituents can increase the generation of nitric oxide, hydrogen peroxide, cytokines tumor necrosis factor-, and interleukin-6 [80]. The binding ability of protoplasts and cell-free extract of three strains was determined in another study, revealing that the cell membrane was not the primary binding site and that B[a]P is not eliminated by metabolism. These observations highlight the relevance of cell wall preservation in B[a]P binding and support the existence of a cell wall-related physical phenomena that opposes metabolic breakdown [55].
Bifidobacterium's potential mechanisms of detoxifications are therefore linked to their ability to bind the toxic compounds due to the presence of peptidoglycan and polysaccharides in the cell wall [82]. As in the Lactobacillus cases, the incubation time and viability -cell wall integrity strongly affects their biodetoxification ability [55,82].

Probiotic Yeasts and Their Biodetoxification Capacity
The genus Saccharomyces, more exactly S. cerevisiae strain is the most widely used for baking, alcoholic fermentation, and nutritional supplements for people and animals. Due to their inclusion in the Generally Recognized as Safe group, these species, together with LAB, offer an appropriate starting point for finding strategies to decrease food and human exposure to chemical contaminants [69,73,86,87]. Some yeast species (Table 3) have been used as biocontrol agents to prevent mycotoxin-producing filamentous fungus from growing on crops, food, and feed [86]. These species might help preserve agricultural goods and decrease mycotoxin contamination. In different technological processes, yeasts can be used for their direct inhibitory impact on pollutants, particularly mold toxin generation, independent of their growth-inhibiting effect [69]. Several yeast species' cell walls can also bind mycotoxins from agricultural goods, successfully sanitizing them. Mycotoxicosis in cattle is also treated using probiotic yeasts or foods containing yeast cell walls or other ingredients. Yeasts are also known to have additional beneficial properties, such as breaking poisons into less harmful or even non-toxic forms [72]. Yeasts and their biotechnologically necessary enzymes may be sensitive to particular mycotoxins, posing a severe challenge to the biotechnological field, but unfortunately, yeast-mycotoxin interactions have been seriously understudied [70,86,88]. Filamentous fungus development and/or decreased gene expression involved in mycotoxin production can be limited by the yeast-generated metabolites. The main volatile organic compounds generated by Pichia anomala (fungi biocontrol agent), 2-phenylethanol (2-PE), have been shown to hinder spore germination and toxin production; in other words, biosynthesis was suppressed [87]. Yeast's capacity to bind ochratoxin A increased during fermentation with two Saccharomyces strains by the addition of anthocyanin [86].
The yeast cell integrity seems to be the most important factor that influences the efficacity of yeast-related biodetoxification. Namely, cell surface areas, volume, cell wall thickness, and the presence of O-H/N-H bonds of proteins, polysaccharides, and 1,3-βglucan from the yeast cell walls [87,89,90]. Parameters such as yeast exposure time, yeast concentration, initial toxin concentration, and temperature are the ones mentioned by the scientific literature as being influencing factors in the biodetoxification process [87,91]. In contrast to Lactobacillus, yeast's capability to bind mycotoxins is not significantly influenced by cell viability. The main condition for the inactive yeast cells was the cell wall wholeness. Destroyed yeast cells proved with almost 50% less biodetoxification capacity [90]. PAT-patulin; OTA-ocratoxin; AFB1, AFB2, AFG1, AFG2, AFM1-aflatoxin B1, B2, G1, G2, M1; As-arsenic; ↑-increase.

Other Probiotics or Promising Probiotic Candidates and Their Biodetoxification Capacity
Several probiotic species and promising probiotic candidates (Table 4) have different biodetoxification activities. Probiotics may use several mechanisms (such as epoxidation, hydroxylation, dehydrogenation, and reduction) or metabolites (antimicrobial proteins) for the toxins' degradation [88,93]. Bacitracin A, for example, is a non-ribosomal peptide antibiotic developed by Bacillus licheniformis strain HN-5 with high antibacterial activity. Bacillus spp. are rod-shaped, Gram-positive, endospore-forming organisms that can be obligate aerobes or facultative anaerobes and are a potent antibiotic against Gram-positive and -negative bacteria. The bacABC operon and bacT, which encode non-ribosomal peptide synthetase and thioesterase, respectively, make up the bacitracin synthetase gene cluster in B. licheniformis. Commercially B. licheniformis is utilized in the manufacture of bacitracin, an extensively used animal feed. The processes behind bacitracin's ability to reduce infectious illnesses in animals have previously been studied [94]. Often utilized in producing industrial enzymes, including amylase and protease, Bacillus licheniformis is a common bacteria found in soil and waste organic material. According to a prior study, several strains of B. licheniformis have a lot of promise as probiotics or nutrition supplements for humans [93]. After 36 h of incubation, B. licheniformis CK1 reduced ZEN by 95.8% in Lactobacillus broth by degradation of the mycotoxin (the HPLC chromatogram B. licheniformis CK1 cell wall revealed no ZEN). The authors believe that the extracellular xylanase, cellulase, and protease produced by B. licheniformis CK1 are responsible for the degradation. According to the data, ZEN at a concentration of 2 ppm was not harmful to B. licheniformis [95].
Not so commonly used probiotic strains, such as Pediococcus acidilactici RC005 and P. pentosaceus RC006, absorbed between 26% and 34% of aflatoxin M1 from milk, from a concentration of approx. 30 and 34 ng/mL. The authors also discussed the desorption phenomena observed in 100% of the tested yeasts strain [88].
Future studies need to sustain the less-studied probiotic genera's (other than Lactobacillus, Bifidobacterium, and Saccharomyces) biodetoxification capacities and elucidate their mechanisms of action.

Probiotic Antimutagenic Activity
It has been proven that genotoxic substances and antibiotics created in the human body can induce genetic mutations and carcinogenesis [99]. As a solution to this effect, it is recommended to use antimutagens to prevent genetic mutations transmitted by some foods, cancers, or tumors. Antimutagenics are substances that can reduce the occurrence of mutations at the cellular level, acting on DNA replication and repair [100]. Antimutagens use chemical or enzymatic pathways to annihilate mutagens' actions.
The autochthonous microflora in the human GI tract is wide-open to genotoxic compounds at high frequency. Some bacteria in the gut can efficiently bind mutagenic pyrolysates to decrease their mutagenicity. Bifidobacteria are among the more significant bacteria in the human gut with this effect [34]. They are used as probiotic dietary supplements.
It was also demonstrated that probiotics could act as immunomodulators by influencing the gut-associated lymphoid tissue distributed throughout the GI tract [101]. Additionally, literature reports that probiotics can produce butyric and acetic acids with antimutagenic activity (can fight chemical mutagens or promutagens). Thus, these properties are associated with the consumption of viable and able-to-colonize probiotic cells. Compounds that diminish the effects of the mutagen are classified as desmutagens or bioantimutagens. Desmutagens act in a chemical or enzymatic direction by inducing inhibition of the mutagens' activity. Meanwhile, bioantimutagens act on DNA replication and inhibit the effects of the mutagen [102].
Another side of probiotics and their antimutagenic effect is how they could be introduced into humans' diets in an effective manner. Thus, a key characteristic of probiotics present in functional foods is viability. Among these types of functional products is yogurt. Yogurt is an excellent matrix used for probiotics delivery, with the mention that it should contain a minimum number of 10 6 CFU/g probiotics at the time of use. Several factors such as pH, water activity, oxygen, strain type, and other strains influence this [11,16]. The adverse effects of probiotics could be minimized by different strategies, such as microencapsulation of probiotics, the addition of enzymes, and prebiotics [103].
DNA alteration and carcinogenesis may be induced by the increase in mutagens and promutagens in the system [102]. Scientists have proven that butyric and acetic acids, of probiotic nature, have a broad antimutagenic activity. Thus, GI disorders may be reduced using probiotics, which can avoid the hazard of DNA genotoxins. Probiotics act as immunomodulators by influencing the gut-associated lymphoid tissue distributed throughout the GI tract. To have a positive impact on human health, probiotic cells need to be able to colonize the intestine. For L. acidophilus and Bifidobacterium spp., their products of fermentation are probiotic bacteria that provide antimutagenic and anti-carcinogenic activities.
It has been reported that activating carcinogenic enzymes, such as nitroreductase, βglucuronidase, and azoreductase, are inactivated or L. acidophilus reduces their activity [104].
By fermenting milk with different Lactobacillus strains to obtain the yogurt, more peptides are formed, which present various bioactive compounds. These compounds have positive effects on consumer health, namely antimutagenic and antioxidative effects. Simultaneously, bioactive compounds are used to create functional foods and increase some foods' shelf life through the antioxidant effect [105].
L. paracasei subsp. tolerance JG22 also has a positive effect on the control of compounds that can express mutagenesis. There are some proven valuable characteristics of this strain, namely, high resistance to an acid environment (pH 2.0) and bile salts (0.5%), resistance to different antibiotics, and an adequate ability to colonize the gut [102]. The authors conclude that L. paracasei subsp. tolerance of JG22 is an excellent probiotic to be included in functional foods to prevent colon mutagenesis or tumorigenesis [102,106]. Therefore, only viable probiotic cells can inhibit or bind mutagens.

Anti-Carcinogenic Effect of Probiotics
Cancer is a pathology caused by multiple triggers. Our World in Data reports cancer as the second cause of death worldwide [107]. Food carcinogens formed in foods cooked at high temperatures and inadequately stored or contaminated with raw materials (heterocyclic amines (HCA), polycyclic aromatic hydrocarbons (PAH), mycotoxins (aflatoxins), N-nitroso compounds, acrylamide, and heavy metals) increase the potential risk factors for cancer [61,100]. In the GI tract, probiotics connect and degrade carcinogenic compounds [108,109]. The cell wall of probiotics may be an essential factor in binding free toxins in the intestine [104].
Factors, such as genetic predisposition, personal diet, lifestyle, physical activity, obesity, type 2 diabetes, abusive alcohol use, inflammation, and smoking, significantly influence carcinogenesis [110]. Several studies have confirmed that some opportunistic microorganisms, such as Bacteroides fragilis, Fusobacterium nucleatum, Helicobacter hepaticus, Streptococcus bovis, and E. coli, may indicate different types of cancer [7].
There are several pathways attributed to the anti-carcinogenic effect of different probiotics (Table 5). Among these, the most stated ones are the alteration and deactivation of carcinogens or mutagens, decreasing pH of the gut environment regulating the gut microflora and suppressing the growth of carcinogenesis microbiota, immunomodulatory properties (such as increased peripheral immunoglobin production, stimulation of IgA secretion, and decreased pro-inflammatory cytokine production), modulation of apoptosis (through SFCA production, and glutathione transferase activity stimulation), sustain cancer cell differentiation (through butyric acid action), inhibition of the tyrosine kinase signaling pathway, and DNA protection from oxidation [19,80,111,112]. Cancer cell proliferation is inhibited by probiotic action by making the cells more susceptible to apoptosis [8]. These mechanisms involve activation of pro-caspases, decreasing the anti-apoptotic Bcl-2, and increasing the sensitivity of pro-apoptotic Bax proteins.
The scientific literature reveals that living or dead probiotic cells, their components (cell wall, peptidoglycan, and cytoplasmic fraction), or metabolites (exopolysaccharides, SCFA) can produce substantial antiproliferative effects in cancer cell lines [81,113]. Figure 3 describes the probiotic mechanisms reported in the scientific literature responsible for their anti-carcinogenic activity.

Conclusions and Perspectives
This paper focuses on the protective and biodetoxification capacities of different probiotic strains. Probiotics are popular for their role in different pathologies, mostly in the intestinal related ones. Their impact on gut microorganisms is crucial because they can positively (i.e., biodetoxification from mycotoxin, fungi, acrylamide, metals, virus, reduce pro-inflammatory responses, antimutagenic and anti-carcinogenic activities) and nega-  ↓-decrease/downregulating; ↑-increase/upregulating, CRC-colorectal cancer, IL-6-cytokine related with bad prognosis in advanced cancers, SeCys-selenocysteine, SeMet-L-selenomethionine, CFU-colony formin units, SCFAshort-chain fatty acid, Bcl-2-B-cell lymphoma 2 with role in apoptosis regulation, Bax gene-modulates apoptosis.

Conclusions and Perspectives
This paper focuses on the protective and biodetoxification capacities of different probiotic strains. Probiotics are popular for their role in different pathologies, mostly in the intestinal related ones. Their impact on gut microorganisms is crucial because they can positively (i.e., biodetoxification from mycotoxin, fungi, acrylamide, metals, virus, reduce pro-inflammatory responses, antimutagenic and anti-carcinogenic activities) and negatively (i.e., transfer of antibiotic resistance) modulate human health. Considering that consumers respond differently to probiotics according to age, genetic characteristics of gut bacteria, diet, antibiotic use, and environmental cues, precautions are necessary before their use, and for this reason, they should be recommended only by health care personnel/clinicians, while more concerns are in their market distribution.
The biodetoxification mechanisms of the action of probiotics belonging to Lactobacillus, Bifidobacterium, Saccharomyces, and other types of more or less popular genera (Bacillus, Enterococcus, Escherichia, Streptomyce, Pediococcus) are proved to be influenced by factors specific to (i) bacteria genus and strain; (ii) environmental dependent factors; and (iii) toxin dependent factors. Probiotics belonging to Lactobacillus are the most studied ones and are more correlated with the ability to bind toxins (mycotoxins, heavy metals, etc.) on the cell wall. Reactive functional groups and compounds present in the cell wall, such as proteins, peptidoglycan, and polysaccharides; 1,3-β-glucan for the yeast cell wall, are recognized to be responsible for probiotic binding capacity. The differences between the strains in relation to toxin absorption and binding are given probably due to the diversity in cell wall structures and bacterial cell membranes.
Other probiotic biodetoxification pathways are correlated with probiotic metabolites, co-cultivation of different probiotics or different probiotic/compound formulations (i.e., lactulose), gene expression, and sustaining fecal excretion.
Due to the fact that probiotics decrease toxin absorption and by reducing its toxicity, they are correlated with strong anti-carcinogenesis and anti-mutagenesis action.
Based on a thorough review of the capacity of probiotics to react with pathogens, fungi infection, mycotoxins, acrylamide toxicity, benzopyrene, and heavy metals, we conclude that specific probiotic strains and combinations offer significant health outcomes and positively impact in vitro and in vivo detoxification processes. Despite the fact that there are many publications on the biodetoxification properties of probiotics, their application in practice in the detoxification of food and/or feed has been narrow. To increase this utilization, we concluded that specific mechanism pathways should be elucidated, the toxicity of degradation products should be also studied, and there should be safety regulation on the use of probiotic strains towards food matrices and in vivo systems.

Conflicts of Interest:
The authors declare no conflict of interest.