Povidone-iodine is a highly effective broad-spectrum disinfectant widely used in the fields of medical care, animal husbandry, aquaculture and food processing. However, if the concentration is not properly controlled, especially if it is overused, it will cause a series of serious problems. Understanding the hazards of excessive use of povidone-iodine is of great significance to protecting human health, animal and plant safety and food safety.
Table of contents
●The impact of excessive use of povidone iodine in the medical and health field
●The consequences of excessive use of povidone iodine in the livestock breeding field
●The hazards of excessive use of povidone iodine in aquaculture
●The risks of excessive use of povidone iodine in the food processing industry
●Industry measures to deal with excessive use of povidone iodine
The impact of excessive use of povidone iodine in the medical and health field
In medical and health scenarios, povidone iodine is often used for skin disinfection, mucosal washing and wound treatment. If used excessively, it will cause direct harm to the human body. When used for skin disinfection, excessive concentrations of povidone iodine will destroy the normal physiological structure of the skin surface, causing irritation reactions such as redness, itching, and desquamation. Studies have shown that when the effective iodine content of povidone iodine solution exceeds 1.5%, the incidence of skin irritation reactions increases significantly, and some sensitive people may even suffer chemical burns.
In terms of mucosal washing, the risk of excessive use is higher. Taking vaginal washing as an example, when the concentration of povidone iodine solution exceeds 0.05%, it will destroy the acid-base balance and normal flora ecology in the vagina. Under normal circumstances, the pH value in the vagina is maintained at 3.8-4.4. Excessive povidone iodine will increase the pH value, inhibit the growth of lactobacilli, and thus increase the risk of infection by harmful bacteria such as Candida. Clinical data show that patients with vaginal inflammation caused by excessive use of povidone-iodine for vaginal douching account for 12% of the related medical cases.
For wound treatment, excessive use of povidone-iodine will delay wound healing. High concentrations of povidone-iodine will damage new cells and tissues around the wound and hinder collagen synthesis. Studies have found that the use of povidone-iodine with a concentration higher than 0.7% to treat wounds will extend the healing time by 3-5 days compared to normal.
Consequences of excessive use of povidone-iodine in animal husbandry
In the animal husbandry industry, povidone-iodine is used to disinfect the farm environment, the surface of livestock and poultry, and drinking water. If used excessively, it will cause great harm to the health of livestock and poultry. When disinfecting the farm environment, if the concentration of povidone-iodine solution exceeds 0.5%, the residual disinfectant will irritate the respiratory mucosa of livestock and poultry, leading to an increase in the incidence of respiratory diseases such as coughing and wheezing in livestock and poultry. Monitoring data from a large-scale pig farm showed that the incidence of respiratory diseases in pigs increased from 5% to 15% due to excessive use of high-concentration povidone-iodine for pen disinfection.
When disinfecting the surface of livestock and poultry, excessive use of povidone-iodine will burn the skin of livestock and poultry and destroy the skin barrier function. When the solution concentration exceeds 0.3%, the probability of erythema and ulceration on the skin of young livestock and poultry such as piglets and chicks increases significantly. In drinking water disinfection, when the povidone-iodine concentration exceeds 0.002%, the amount of water consumed by livestock and poultry will be reduced, affecting their normal growth and development. Long-term drinking of water disinfected with high-concentration povidone-iodine may also cause thyroid dysfunction in livestock and poultry and reduce immunity.
Hazards of excessive use of povidone iodine in aquaculture
In aquaculture, povidone iodine is used to disinfect water, fish eggs and fish. Excessive use will destroy the ecological balance of aquaculture water and the health of aquatic organisms. When the povidone iodine solution is sprayed throughout the pond, if the concentration exceeds 0.5mg/L, it will not only kill harmful bacteria, but also kill a large number of beneficial microorganisms, such as nitrifying bacteria, leading to the accumulation of harmful substances such as ammonia nitrogen and nitrite in the water, and deteriorating water quality. Due to excessive use of povidone iodine for disinfection in a fish pond, the ammonia nitrogen content in the water soared from 0.2mg/L to 1.5mg/L within a week, causing a large number of fish deaths.
When disinfecting fish eggs and fish, excessive povidone iodine will affect the hatching rate of fish eggs and the health of fish. When the disinfection concentration of fish eggs exceeds 30mg/L, the hatching rate drops by 30% - 50%; if the disinfection concentration of fish bodies is too high, it will damage the gill tissue of fish, affect the respiratory function of fish, and increase the chance of illness.
Risks of excessive use of povidone-iodine in the food processing industry
In the field of food processing, povidone-iodine is used to disinfect equipment, pipelines and personnel hands. If used excessively, the disinfectant residue will contaminate food and endanger the health of consumers. If the food processing equipment is not thoroughly cleaned after disinfection, the residual povidone-iodine will enter the food during the food processing process. Studies have shown that when the amount of povidone-iodine residue in food exceeds 0.1mg/kg, it may have adverse effects on human thyroid function.
If high-concentration povidone-iodine is used for hand disinfection of staff and the cleaning is not thorough, it will directly cause contamination when contacting food. A food processing plant had a batch of pastries with excessive iodine content due to excessive povidone-iodine concentration for hand disinfection of employees. The final product was recalled and the company suffered significant economic losses.
| Application areas | Dangers of overdose | Typical data |
| Medical and health care | Skin redness and swelling, chemical burns; damage to vaginal flora, increased risk of infection; delayed wound healing | When the concentration of skin disinfection exceeds 1.5%, the incidence of irritation reactions increases; when the concentration of vaginal douching exceeds 0.05%, the proportion of patients with inflammation reaches 12%; when the concentration of wound treatment exceeds 0.7%, the healing time is extended by 3-5 days. |
| Aquaculture | Increased respiratory diseases in livestock and poultry; skin burns; thyroid dysfunction, affected growth and development | Excessive disinfection of pig farms increased the incidence of respiratory diseases from 5% to 15%; the probability of skin damage increased when the surface disinfection concentration of young livestock and poultry exceeded 0.3%. |
| food processing | The water ecology is unbalanced, and harmful substances such as ammonia and nitrogen accumulate; the hatching rate of fish eggs decreases, and the health of fish is damaged. | If the disinfection concentration of fish ponds exceeds 0.5mg/L, the ammonia nitrogen content will increase from 0.2mg/L to 1.5mg/L within a week; if the disinfection concentration of fish eggs exceeds 30mg/L, the hatching rate will drop by 30% - 50% |
| food processing | Disinfectant residues contaminate food and affect thyroid function | Residues in food exceeding 0.1 mg/kg may affect thyroid function |
Industry measures to deal with excessive use of povidone iodine
In order to avoid the harm caused by excessive use of povidone iodine, the industry needs to take measures in a coordinated manner. Regulatory authorities should strengthen supervision of the use of povidone iodine products and increase penalties for violations; manufacturers need to optimize product packaging labels and clearly mark the concentration and precautions for use in different scenarios; at the same time, all industries should strengthen training to improve users' awareness of the scientific use of povidone iodine, eliminate excessive use from the source, and ensure safe and healthy development in all fields.