Simple Method of Sample Preparation for Bacterial Counts in Quality Control of Frozen Vegetables 1.

Samples of frozen broccoli, cauliflower, mixed vegetables, peas and corn were prepared for coliforms, enterococcal and aerobic plate counts by: (a) official blending technique, (b) shaking in dilution blanks by hand, and (c) by dry dispersion in plastic bags with an in-house-made press (SVC-Press) followed by addition of diluent and hand shaking. Bacterial counts with the SVC-Press were comparable to those of the standard blending method and superior to those of the shake bottle method used for quality control in many food industry operations. The press was made of aluminum and plexi-glass with simple tools at a cost of $365.00. The SVC-Press provides bacterial recoveries statistically comparable to blending along with simplified sample handling, reduction in labor cost and instrument cost affordable to small frozen food industrial operations.

Evaluation of a Membrane Filter Test Kit for Monitoring Bacterial Counts in Cannery Cooling Waters.

Performance of the Millipore SPC Sampler was compared with the Standard Plate count method for routine checks of bacterial counts in cannery cooling waters. Methods were tested with cooling waters from a hydrostatic retort. Recovery of viable bacteria was very low when the Millipore samples were incubated for 24 h, but incubation for 48 or 72 h consistently yielded higher counts with the Millipore than with the standard method. Duplication of counts between analysts was approximately equal with both methods. Replication of bacterial counts within samples was more erratic and skips were more frequent with the Millipore than with the standard method. Procedures to control replications and skips are discussed. The Millipore procedure is a convenient alternative to the Standard Plate Count for routine quality audit of cannery cooling waters.

Microbiological Studies on Aging of Intact and Excised Beef Muscle 1.

Beef cattle from the University herd were used for these studies; aging treatments after slaughter were as follows: (a) sides were held at room temperature (21-23 C), (b) sides were held at 2 C, (c) sides were kept for 6 hat room temperature and then the round was removed and placed at 2 C for 18 h (d) sides were held for 3 days at 2 C, then the excised round was kept for 4 days at 2 C for a total of 1 week of low temperature aging. After aging by procedures described, steaks were cut from the round, packaged and stored in a display case at about 5 C. Similar treatment was given to ground beef prepared from the same round muscles. Holding an entire side of beef at high temperature for 24 h promoted bacterial growth on the surface with subsequent proliferation on retail cuts. Shortening the aging treatment at high temperature resulted in reduced bacterial populations on packaged items. Highest bacterial loads and most rapid spoilage resulted from excising the muscle after low temperature holding and then continuing to hold the muscle in the cooler. This treatment was even more conducive to spoilage than was holding at room temperature for 24 h, and is not to be recommended.