Hello all,
I found this post via google, it is rather informative although I have no idea regarding the source of the information.
"Fill a quart container full of water and freeze it solid. What will happen? Water turning into ice expands. It will rupture the container if there is no 'give' to it.
The same happens inside a cell in a piece of meat. When frozen, the moisture inside the cell expands and will rupture the cell wall. When unthawed, that moisture will escape through the rupture and becomes 'juice' (purge is the correct term) in the bottom of the COV or pan or on the counter, leaking out. We all know to put towels under a product we're thawing out to capture this runoff. But, this purge is drawing the natural flavor, moistness and juiciness of that piece of meat out of it. This is what freezing does to meat.
Now, there are different levels of freezing. There's hard freezing at below zero, freezing to complete hardness all the way through, maximum expansion. This does the most damage. A good example of this and what effect it has is turkeys. These are killed and hard frozen sometimes years before going to market; they have an approximate 3 yr shelf life. You've see blow-out sales prior to holidays for 29¢ / lb birds; they're at the end of their shelf life and have to be sold or thrown out. Now are they totally shot? No, not at all. But they will be dry if cooked too long as what moisture is left after thawing in each cell will evaporate quickly. These should be cooked to no more than 155-160° maximum, not the recommended 180° on the package (anything over 135° you've killed any bacteria unless you've unthawed improperly, like on the counter until the bird is room temp - if so, throw it out!).
Then there's 'hard chill' freezing. This is just to 32° - point of freezing. This technically freezes the outer cells but to the least level of damage and interal cells can be at slightly higher temp but still in 'suspended animation' where bacteria will not grow. Chicken is a good example. Chicken cut up and pre-packaged in a packing plant (like Tyson, Pilgrim, etc.) is passed through a nitrogen 'quick chill' cooling process that puts a 'hard chill' on the product for transporting. Held in reefers at 32° it arrives across the country in a barely hard state but bacteria growth has been minimal to none. You can press on it and it will give even though it is hard, so it has done almost no damage to the flesh. Laying it out in the meatcase in the morning at 38° to 40°, a quick sheen of frost shows then the packages are new and fresh and ready to sell as if the 4 day trip to the distributor and 2 day hold time until redistributed had never happened, the shelf life stamped on the package well ahead of that day's date to insure freshness. This key procedure is what is allowing central meat processing to take over the meatcutting industry and taking individual meatcutters out of every Walmart in the country. It's applied to beef, pork and chicken and offals, etc. - hard chilling for transport and distribution storage until delivered to the end destination.
In the case of pork, almost all is frozen and held at under 5° for 20 days (or -4° for 3 days), this is 'certified' pork. Freezing in this manner does one thing well. It kills the trichinosis worm that is most likely to be in pork. However, many species of trichnae are resistant to freezing and invade game animals so freezing will not kill those, only cooking will. Here's a chart on cooking times and temps minimum from Wikipedia
:
Larvae may be inactivated by the heating, freezing (caution), or irradiation of raw meat. Freezing may only be effective for T. spiralis, since some other species, such as T. nativa, are freeze resistant and can survive long-term freezing. [11]
Unsafe and unreliable cooking of meat includes the use of microwave ovens, curing, drying, and smoking, as these methods are difficult to standardize and control. [11]
Cooking meat products to an internal temperature of 165 °F (74 °C) for a minimum of 15 seconds.
Cooking pork to a minimum uniform internal temperature per USDA Title 9 section 318.10 Table below. It is prudent to use a margin of error to allow for variation in internal temperature and error in the thermometer.
°F °C Minimum Time
120 49 21 hours
122 50.0 9.5 hours
124 51.1 4.5hours
126 52.2 2 hours
128 53.4 1 hours
130 54.5 30 minutes
132 55.6 15 minutes
134 56.7 6 minutes
136 57.8 3 minutes
138 58.9 2 minutes
140 60.0 1 minute
142 61.1 1 minute
144 62.2 Instant
Freezing pork less than 6 inches thick for 20 days at 5 °F (?15 °C) or three days at ?4 °F (?20 °C) kills larval worms.
Cooking wild game meat thoroughly. Freezing wild game meats, unlike freezing pork products, even for long periods of time, may not effectively kill all worms. This is because the species of trichinella that typically infects wild game is more resistant to freezing than the species that infects pigs.
So, freezing does denegrate the meat vs. fresh, but to what extent depends on the type of freezing, the length, to what depth, and it is beneficial in the case of pork or transportation."
It seems that the rupturing of cells on frozen meat would change the terrain and allow for proliferation of pathogenic bacteria in certain situations. Have people had success making high-meat using lightly or heavily frozen meat?
I have a vacuum sealed grass fed chuck roast that no longer seems vacuum sealed, it has been stored in my shoddy freezer for a month but who knows how old it was when it was packaged i got it from some amish girl, is there any risk of botulism in vacuum sealed meat package if it is stored to warm for too long?
Topic: Dangers of thawing and refreezing (Read 68639 times)