Certain biological and physical parameters of vacuum packaged fresh pork sirloin roasts

"The preservation of meat has always presented a complex problem to man. The first means of preservation was probably rubbing salt onto the meat surface. This dried out the surface enough and produced a high enough salt concentration to inhibit the growth of spoilage organisms. It is believed that the salt used at first contained many impurities such as salt peter (sodium nitrate), which were also inhibitory to spoilage organisms. The meat would last longer than fresh unprotected meat, but the high salt concentration produced a rather unpalatable finished product. New means of preservation were provided with an increase in technology. A new method of preservation was developed by Nicholas Appert in the late 1700's. He found that foods heated in sealed containers lasted longer than foods that were unprotected as long as the container was not opened. This finding developed into the canning industry. Refrigeration was the most important technological advancement in meat preservation since canning. The reduction in temperature down to 0-5 [degrees] C decreased the rate of growth of spoilage organisms. Refrigeration greatly expanded the length of time meat could be stored. Meat could be transported further with increased shelf-life and storage time at home was increased. With the advent of refrigeration in the retail store, meat could be individually packaged and self-service meat cases evolved. The retail shelf-life was still limited to several days because the meat packaging material was oxygen permeable and provided an environment for bacterial growth. New types of packaging systems have been introduced that replace or remove oxygen and thus inhibit spoilage bacterial growth. Different gasses have been used to replace oxyqen to extend the storage life of meat. Carbon dioxide has been used successfully to replace oxygen and has caused significant increases in storage time (Baran et al., 1970; Huffman, 1974). Huffman, (1974) also reported using nitrogen to replace oxygen, but found no decrease in bacterial counts. In addition, Pierson et al., 1970, reported finding no difference between vacuum packaging and nitrogen gas packaging. Vacuum packaging excludes oxygen from the meat package thereby inhibiting aerobic spoilage organisms. Oxygen impermeable films have been developed to facilitate vacuum packaging. The use of vacuum packaging has become very popular in the distribution of beef wholesale cuts. Vacuum packaging of pork has not been utilized much in industry to date. Very little is known about the effects of vacuum packaging on pork. The objectives of this research were to determine: 1. The impact of (a) chill method and storage temperature and (b) meat quality on weight losses, tenderness, and oxygen saturation of the purge in vacuum packaged fresh boneless pork sirloin roasts. 2. The impact of leakers on (a) the subsequent microbial profile population and (b) fresh meat color after three days of retail display of vacuum packaged fresh boneless pork sirloin roasts."--Introduction.