Shelf life extension of liquid whole eggs by heat and bacteriocin treatment

During a 15-month period, samples of commercially pasteurised liquid whole egg (LWE) were tested for the presence of spoilage microflora. The total bacterial counts were 2.2+/-0.6 log CFU/g and total lactic acid bacteria (LAB) counts were 1.9+/-0.6 log CFU/g. Enterobacteriaceae were detected in 2 samples. Out of the tested samples, 45 LAB were isolated and identified, with 30 strains identified as Enterococcus faecium, 12 as Enterococcus faecalis, and 3 as Lactobacillus paracasei subsp. paracasei. All strains, except 6 strains of E. faecium, possessed lipolytic activity. All the E. faecalis strains and one strain of E. faecium showed a high proteolytic activity, while moderate proteolytic activity was shown by 3 lactobacilli strains. Minimum inhibitory concentration of nisin and Micocin X was measured against groups of isolated strains, and ranged from 10.4 microg/mL to 41.7 microg/mL for nisin and from 0.2 mg/mL to 1.6 mg/mL for Micocin X. The LWEs supplemented with 6.25 mg/L of nisin or with 500 mg/mL of Micocin X were pasteurised at 65 deg C for 2.5 minutes. The shelf life of LWE with the addition of nisin or Micocin X stored under refrigerator conditions was extended by a minimum of 5 weeks.