INHIBITION OF Staphylococcus BY ILACTIC ACID BACTERIA IN COUNTRY‐STYLE HAMS

Lactic acid bacteria were tested for inhibition of staphylococci prevalent in country‐style ham. Tests were conducted in broth and agar media and in a model meat system. Lactobacillus plantarum and Pediococcus cerevisiae were selected as antagonists against a strain of Staphylococcus epidermidis isolated from country‐style ham. Culture introduction into muscle tissue was more effective by syringe injection than surface or puncture application. The model meat system was applied by using 27 hams in a 3 × 3 × 3 cubed factorial design experiment. The three factors were as follows: Sucrose at 20, 40, 60% of curing mixtures; salt equalization time at 0, 1, or 2 wk; and inoculation with either L. plantarum at 2.2 × 10 8 , P. cerevisiae at 1.6 × 10 8 , or S. epidermidis at 3.4 × 10 5 cells/g of ham. Seventeen hams had at least some putrefactive spoilage due to Clostridium sporogenes or Proteus vulgaris. Spoilage was greatest at 0 time in equalization and for lowest sucrose levels. Ham pH was successfully monitored during processing by placing a pH probe in desired muscle areas, but this appeared to contribute to spoilage. L. plantarum inhibited S. epidermidis when the 60% sucrose treatment was used and acid production appeared necessary for staphylococcal inhibition to occur.