Are blood spots in eggs developing into chicks?
As the fear of fat recedes, and the danger of carbohydrates looms on the horizon, the consumption of eggs is rising. Increasing consumption is followed by increasing questions and concerns about the commercial supply of eggs. One of these concerns regards the existence of blood spots. Many people believe that the presence of a blood spot indicates the beginning of a young chicken. A little known fact is that eggs sold for consumption are usually infertile. According to Dr. Frank Robinson, Associate Dean of the Faculty of Agriculture at the University of Alberta, “The average person is probably unaware that hens can lay an egg without knowing a rooster at all.” Without the hens being bred, the eggs produced by a chicken are not fertile, and cannot develop into chicks. Another concern is that these eggs are unsafe to eat. This is also untrue. Blood spots are not an indicator of egg contamination.
So what are blood spots? The female chicken’s reproductive system contains one ovary and an oviduct, which provide the machinery to form eggs. The yolk is the ovum that is released from the ovary. It passes down the oviduct and is coated in albumen (egg white). Near the end of the oviduct the shell is formed over the egg and then it is laid. Before it is released from the ovary (a process called ovulation), the yolk grows inside a membrane called the follicle wall. This covering ruptures releases the yolk by splitting along a line called the stigma. Normally this line is avascular, meaning that it contains no blood vessels. If there is a vessel crossing this line, it will rupture when the yolk is released. A small amount of blood will adhere to the yolk while the rest of the egg forms over it.
In commercial egg layers, the incidence of blood spots is directly related to the stress level of the laying hens. Stress factors include sudden loud noises, inappropriate housing, feed and water regimes. Careful management prevents most of these stress factors. “Some producers play soft music in their barns to dampen outside noises” states Dr. Robinson. Other factors that may affect the incidence of blood spots include activity level, age, vitamin balance and genetics. There is a slightly higher incidence of blood spots laid in brown eggs. Some research on this topic is being done at the University of Alberta. One study suggests that hens which lay brown eggs produce 25 times more blood spots. Through selection, the levels of blood spots are being reduced in all strains of laying hens. According to Dr. George Ansah, lead geneticist for Hubbard ISA, “All breeding programs in Canada focus on improving internal egg quality in both brown and white egg layers. Genetic selection of hens is one way of improving the final product for the consumer.”
Management and selection greatly reduce the already low level of naturally occurring blood spots, however, there is another reason that very few blood spots are found in commercial eggs. After eggs are collected from the hens, they are moved along a conveyor belt over a very bright light in a process known as candling. The light penetrates the shell and glows through, allowing a spotter to see any defects inside the egg. If a meat spot or a blood spot is seen, the egg is removed from the production line or downgraded to “B”. “Few grade B eggs get to grocery store level. For the most part, such eggs go to further processing – for use in other products requiring eggs” asserts Brenda White of the Alberta Egg Producer’s Board. In brown eggs small blood spots are more difficult to see because the light shining through the shell glows red.
The brown egg market is still small compared to the standard white egg market. Recently it is also losing ground to specialty eggs. Brenda White stated, “For the first time ever in the many years that this research has been done omega-3 eggs were the number two most purchased egg choice of Albertans, positioning brown shelled eggs to third place.”
Eggs with blood spots are removed because they are unappealing to the consumer, not because they pose a health risk. A contaminated egg will generally look perfectly normal, while one with a defect may be safe. The best way to prevent egg-born illness is to properly handle and cook eggs before eating them. Most egg born illness are actually picked up by cross-contamination in the kitchen. Those human illnesses that can be transmitted directly from the hen are destroyed by cooking. If a spot is unappealing, it can be removed easily with the tip of a clean knife before the egg is cooked.
Blood spots naturally occur at a low level as a consequence of the way eggs are formed within the hen. They do not represent the beginning of chick development. In fact, the hens that produce commercially marketed egg are not bred. The eggs they lay areusually infertile and could never mature into chicks. The exception is when there is an over abundance of hatching eggs, and some of these eggs may end up in the table egg market.
- Ken Lopes, Ken Schur, Chelsea Whittaker
What's all the range about beef jerkey anyway?
Did you know that the word “jerky” originated from the Incan term Charqui (shar-kee), meaning dried meat? Thousands of years ago, prior to refrigeration, meat that was not immediately used was dried for later use. The meat was thinly sliced and hung over a smoky fire to give it flavour. The result? One of the earliest applications of food
preservation. This method enabled ancient peoples to use the meat as a staple during the long winter months without it spoiling.
Today, meat is still dried to make jerky. It is made by trimming the excess fat off of the raw meat; it is then thinly sliced, marinated in a curing solution, and dried. This preserves the meat, provides a better taste, and a longer shelf life. During the drying and dehydration process, the moisture content of the meat is reduced from 75% (raw) to 20-40% (dried) to limit the growth of microorganisms such as bacteria, yeast, and moulds which require a specific amount of water for survival. There are various methods that may be used to dry the meat, although not all are recommended, as it is difficult to maintain a steady, controlled dry heat. Food processing companies use large drying ovens. This method is safer than using a conventional oven or a food dehydrator.
In any food processing facility, Hazard Analysis Critical Control Points (HACCP) are very important. The HACCP system is designed to prevent the occurrence of any problems that may occur during food processing. This is achieved by ensuring that there are controls in place throughout the production process where any potential danger exists, such as biological contamination, or personal injury. One must prevent the growth of micro-organisms during processing and in the final product. When jerky is processed, biological contamination is controlled by regulating the time and temperature of the drying process.
Once the meat has been dried to 20-40% moisture content, it is cooled and packaged in a vacuum-sealed bag. The vacuum-sealed package is designed to remove as much oxygen as possible from the package to prevent spoilage of the jerky due to oxidation. Proper packaging of the jerky also contributes to its long shelf life.
Commercially-packaged jerky has a shelf life of 12 months in comparison to the 1-2 month shelf life of home-made jerky. Home processing is becoming increasingly popular among hunters and farmers who find themselves with a large quantity of meat at one time. Ryan Campbell utilizes a home processor to make deer jerky: “I have no room left in my freezer. Making jerky lets me store some of the meat in my fridge without it going bad too quickly.”
According to Michael Tratch from Cameron’s Meats located in Edmonton, Alberta, jerky is usually made from the “outside round, inside round and eye of round.” While any cut from the animal may be used for jerky, prime cuts are normally used to make products with larger profit margins like steaks and roasts. Jerky provides a use for cuts that are originally of lower quality.
The success of jerky is not limited to just beef: jerky can be fashioned from almost any meat. Forms of jerky have been developed from bison, elk, turkey, deer, and even salmon. Outside Canada, jerky is made from unique animals like emus, crocodiles, and kangaroos. Though not as common as beef jerky, other forms such as bison jerky are gaining popularity. The strength of beef jerky as a product goes along with the recent popularity of diets like the Atkins Diet. Protein-based diets, such as this one, support snacking on products like beef jerky as opposed to
high-sugar foods. With its long shelf-life, high-protein, low carbohydrate and low fat content, it’s the ideal snack for hikers, bikers, campers, and any outdoor enthusiasts.
Have you ever considered jumping on the beef jerky band wagon? Not only is it convenient, it’s a traditional food, with multiple nutritional benefits, and enough flavour choices to ensure that your favourite is on a shelf somewhere.
- Graham Collier, Nadin Laffin, Connor LaForge and Wendy Sheane
