With emergence of antibiotic resistant organisms affecting wound and limited armamentarium available to combat these microorganisms, there has been a big resurgence in use of honey. The use of honey on wounds is not new. There are enough documented evidence that shows honey been used since ancient times on wounds in view of it having healing properties [1-2]. The first mention of honey being used for wound care was in Egypt between 2600 and 2200 BC [3]. In modern era, there is considerable interest among experts who have documented benefits of medicinal honey on wound healing [4]. 

However, honey has to be sterilized for it to be therapeutically used and it is often achieved through gamma irradiation ass heat sterilization destroys various effect enzymes in honey [5].

There are various studies done on effectiveness of gamma irradiation in sterilizing the honey [6-8]. The aim of this study was to assess the long term sterility of Indian honey.

We used sterilized honey that was available at Amit Jain’s Centre for Apitherapy at Amit Jain’s Institute of Diabetic Foot and Wound Care, Brindhavvan Areion hospital, Bengaluru, in this study. The Amit Jain’s Centre for Apitherapy is one of the eponymous wings within the Amit Jain’s Institute for Diabetic Foot and Wound Care that deals with acquisition, sterilization, storage and use of different types of honey on different wounds apart from doing research work on the honey. The Amit Jain’s Centre for Apitherapy is first of its kind that is run by the diabetic foot & wound care specialist and is aimed at propagating the use of honey on wounds in India.

This honey was already sterilized with Cobalt 60 gamma chamber-5000 (GC-5000) by us in 2019 as our centre regularly uses medical grade for wounds. This Indian honey was from giant combs of Apis dorsata bee which is an Indian rock bee.  This honey had yielded Bacteroides species in anaerobic culture and Penicillium species in fungal culture prior to sterilization. It was then subjected for gamma irradiation and dose used was 15kGy. Post sterilization the honey was re-cultured and there was no growth of organisms. We had stored 100 ml of this irradiated honey in a sterile container and this sample was stored in dark room undisturbed. Rest of the medical grade honey was used by us in different wounds. 18 months later, we took the stored honey out and resent the samples to microbiology laboratory. The honey samples were inoculated onto chocolate agar, 5% sheep blood agar and McConkey agar to look for bacterial aerobic growth at 37^O C, thioglycolate media for anaerobic bacterial growth and sabourauds dextrose agar for fungal growth at 37^o C and 25^oC for 2 and 7 days respectively.

We noticed that this gamma sterilized honey that was stored for 18 months yielded no growths and was still sterile and could be continued to be used.

Honey is well known to promote healing through its antimicrobial action, anti-inflammatory effect that decreases odema and exudates and has antioxidant properties [9]. Honey has been used both alone or is incorporated into other dressing materials like alginates and hydrogels [10]. The antimicrobial action of honey is believed to be due to low PH, high osmolarity and enzymatic production of hydrogen peroxide [9]. Research shows honey to be effective against wide variety of organisms like Escherichia coli, staphylococcus aureus, enterococci, pseudomonas, etc [11]. It is believed that honey from different sources can vary 100 folds in the potency of their antimicrobial action [12]. It is used in different wounds like venous ulcers, burns, diabetic foot ulcers, etc [13].

However, it is well known that honey has microorganisms in it especially the raw honey and this honey is advisable to be sterilized before using on wounds [10,14. This honey is then called medical grade honey [6,10,15]. Gamma irradiation is considered to be the mode of sterilization advised for honey as it is does not affect the honey’s antimicrobial properties [16]. Although different studies suggest different doses, we have found 15kgy to be an effective dose in achieving decontamination of the honey [6,16]. 

Though most of us are aware of honey being sterilized effectively with gamma irradiation, there were hardly any studies done that looked into maintenance of the sterility of irradiated honey and period that is could remain free from microorganisms. This simple study shows that even at the end of 18 months of gamma irradiation, the Indian honey was free from microorganisms and it could be continued to be used.

Honey is the new natural antimicrobial that is now frequently advised to be used in wounds that are affected with multidrug resistant organisms. The honey is considered to be medical grade honey once it is sterilized and the commonest mode of sterilization is gamma irradiation. This study shows that gamma irradiated honey remained sterile even after 18 months of storage showing the long term sterility of honey post irradiation. Further studies need to be done on this concept of long term maintenance of honey sterility.

1. Saikaly, S.K. and Khachemoune, A. “Honey and wound healing: an update.” American Journal of Clinical Dermatology, vol. 18, 2017, pp. 237–251.

2. De Rooster, H. and Declercq, J. “Honey for wound care: myth or science?” Flemish Veterinary Magazine, vol. 78, 2008.

3. Song, J.J. and Salcido, R. “Use of honey in wound care.” Advances in Skin and Wound Care, vol. 24, no. 1, 2011, pp. 40–44.

4. Shan, Y. “Medicinal honey in clinical practice: viable alternative or useful adjunct in wound care management.” British Journal of Nursing, vol. 28, no. 12, 2019, pp. S23–S30.

5. Lusby, P.E. et al. “Honey: a potent agent for wound healing.” Journal of Wound, Ostomy and Continence Nursing, vol. 29, no. 6, 2002, pp. 295–300.

6. Jain, A.K.C. and Apoorva, H.C. “Medical grade Indian honey as an effective agent in moisture associated skin damage.” SAR Journal of Medical Case Reports, vol. 1, no. 2, 2020, pp. 21–25.

7. Molan, P.C. and Allen, K.L. “The effect of gamma irradiation on the antibacterial activity of honey.” Journal of Pharmacy and Pharmacology, vol. 48, no. 11, 1996, pp. 1206–1209.

8. Hussein, S.Z. et al. “Does gamma irradiation affect physicochemical properties of honey.” Clinica Terapeutica, vol. 165, no. 2, 2014, pp. e125–e133.

9. Kefani, P.E.P. et al. “Honey clinically stimulates granulation and epithelialization in chronic wounds: a report of two cases.” Medical Journal of Indonesia, vol. 27, no. 1, 2018, pp. 62–68.

10. Cooper, R. “The use of honey in diabetic foot ulcers.” The Diabetic Foot Journal, vol. 25, no. 3, 2017, pp. 154–159.

11. Mandal, M.D. and Mandal, S. “Honey: its medicinal property and antibacterial activity.” Asian Pacific Journal of Tropical Biomedicine, vol. 1, no. 2, 2011, pp. 154–160.

12. Simon, A. et al. “Medical grade honey for wound care: still the ‘latest resort’?” Evidence-Based Complementary and Alternative Medicine, vol. 6, no. 2, 2009, pp. 165–173.

13. Alam, F. et al. “Honey: a potential therapeutic agent for managing diabetic wounds.” Evidence-Based Complementary and Alternative Medicine, 2014, pp. 169130.

14. Jain, A.K.C. et al. “Use of low dose gamma irradiation for honey sterilization.” Wound Asia, vol. 4, no. 1, 2021, pp. 15–17.

15. Jain, A.K.C. and Apoorva, H.C. “Effect of medical grade Indian honey on biofilms: a case series.” Wounds Asia, vol. 3, no. 3, 2020, pp. 26–30.

16. Jain, A.K.C. et al. “Sterilization of Indian honey with cobalt 60 gamma irradiation.” Journal of Apitherapy and Nature, vol. 3, no. 2, 2020, pp. 99–103.