Antioxidants belong to a class of compounds used to retard oxidation of chemicals in foods. These compounds, such as BHA, BHT, TBHQ, PG, etc. are approved to be used in foods by government agencies. In the past 10 years considerable interest has been directed to the antimicrobial properties of these compounds due to the observations by various scientists that many of these compounds can suppress the growth of viruses, protozoa, bacteria, yeast, and molds and their subsequent production of toxic materials in foods. Thus, the dual purpose usage of these compounds (i.e., antioxidation and antimicrobial) has been the subject of many research papers. This review is designed to summarize major publications on this subject as well as present some detailed studies on the effect of major antioxidants on bacteria and mold generated in the laboratory of the author in recent years.

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Butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), tertiary butylhydroquinone (TBHQ) and propyl gallate (PG) at 0, 50, 100, 150, 200, 250, 300, 350, 400, 450 and 500 ppm and selected combinations at 0, 100, 200, 300 and 400 ppm in nutrient agar and in brain heart infusion were tested for antimicrobial activity on sixteen gram-negative and eight gram-positive bacteria. In general, in laboratory media the antioxidants inhibited gram-positive bacteria more than gram-negative bacteria. The antioxidants were more effective in nutrient agar (solid system) than in brain heart infusion (liquid system). In nutrient agar, BHA inhibited the greatest number of organisms followed by PG, TBHQ and BHT, respectively. In brain heart infusion, TBHQ inhibited the greatest number of organisms followed by PG, BHA and BHT, respectively. Of the six combinations tested, the TBHQ-PG combination inhibited the greatest number of organisms followed by BHA-PG, BHT-TBHQ, BHA-TBHQ, BHT-PG and BHA-BHT, respectively. Tests in ground pork indicated the four antioxidants at 100, 200 or 400 ppm significantly (P<0.05) reduced psychrotrophs, coliforms and fecal coliform counts after 4 wk of storage at 4°C. There were no significant differences between the control and the samples treated with antioxidants after either 1 or 2 wk of storage.

The Sudanese dry meat SHARMOOT is a major food product in East Africa. No information is available on microbial profiles or improved methods of processing the product. We have developed a pre-cooking and grinding procedure that produces the meat efficiently. The product is chemically and microbiologically stable for at least 4 months without refrigeration. While staphylococci and Enterobacteriaceae were the most common major bacterial groups isolated from dried meat samples at the beginning, micrococci and bacilli predominated during the last stages of storage. Microbiological data (total, spore, yeast and mold, and Staphylococcus aureus counts and Clostridium perfringens detection) indicated that the product made by us is microbiologically more acceptable than a comparable product made traditionally in Sudan. The potential exists for large-scale production of SHARMOOT.