CONTROL OF CLOSTRIDIUM BOTULINUM AND STAPHYLOCOCCUS AUREUS IN SEMI-PRESERVED MEAT PRODUCTS

Clostridium botulinum and Staphylococcus aureus are naturally occurring contaminants in semi-preserved meat products. They can be inhibited by (a) storage below 3 C, (b) 10% sodium chloride (brine concentration), (c) pH values below 4.5, or (d) proper combinations of these factors. However, most meat products do not have the pH values and brine concentrations required to completely inhibit C. botulinum and S. aureus and there is always a risk of temperature abuse. Improved safety can be achieved by adding 1% or more glucose to the product. The glucose will, in the event of temperature abuse, generally be fermented to lactic acid by the indigenous microflora in the product. As a result, the pH value drops to a level at which the brine concentration is sufficient to inhibit C. botulinum and S. aureus. A better approach to safety is to add, together with glucose, a radiation-killed preparation of lactic acid bacteria, e.g., Pediococcus cerevisiae. Such preparations cause a rapid decline in pH only when the product is exposed to a high temperature, and they are stable during storage of meat products. Addition of irradiated lactic acid bacteria to meat products has not yet been officially approved. Another way to improve the safety of semi-preserved meat is to add sufficient glucono-delta-lactone to reduce the initial pH of the product to a level at which the salt concentration is inhibitory. Use of larger amounts of glucono-delta-lactone may result in flavor and color problems even when the meat product is kept at refrigeration temperatures.