I work in the professional egg world. I know by name the vast majority of people who supervise the production, transport, grading, marketing and delivery of the eggs you find in your grocery stores, restaurants, farmers markets (yes, legally, those eggs need to be professionally graded too), and industrial users of eggs (think bread, cake, cookie, cereal, etc. makers). I know how much care, concern, time, money and worry is dedicated to preserving the safety of eggs. Being a vet, I am very involved in advising on many aspects of egg safety, right from chicken health to giving opinions on egg handling, and even national programs for salmonella control.
We, in the world of Canadian large-scale egg production, are quite proud of our safety record, and the programs we have in place. We often debate whether small producers (read backyarders and hobby farmers) can produce a product that is comparable in safety. We snicker a little at activists that say we need to get away from large-scale farming, since you can produce healthier eggs in your backyard, or on your apartment house roof. How on earth can removing the expertise and care that we provide result in a healthier product? By concentrating the number of birds on a farm, you allow a person to focus strictly on the care and protection of the hens….learn about them and become truly an expert. I admit to having this opinion much of the time.
Many, many people disagree though. “Factory farms”, “industrial production”, “bacterial breeding grounds” have been used to describe professional farms….unfairly, I think, but the terms are sincerely used by many people. The problem is that there are many confounding factors. Depending on what you WANT to read in a paper, almost any study can say anything. Professional, caged farms are much bigger than extensive farms, and exponentially bigger than recreational farms. If there is 1 contaminated egg per 1000 in a cage barn, the farm will produce many contaminated eggs per day. A backyard flock with a rate of 1 contaminated egg per hundred would only have 1 contaminated egg per month. If you eat 2 eggs per day, however, which is safer?
The fact remains (check any activist website for examples) that many studies show that large farms have higher bacterial contamination. Conversely (check any egg farming website for examples) many studies show that professional farms are much safer, contamination wise. So, what’s right?
There is a very recent scientific paper from Spain that describes bacterial contamination that I think is quite balanced. It must be taken with a grain of salt, however, since in North America, all graded eggs are washed, whereas in the EU, this is not the case. Also, the rules on antibiotic use is different. That being said, the study found that there was more significantly more bacterial contamination in free-range, organic and backyard (called “domestic eggs”) production than in free run (birds free inside of a barn), while cage barns had the least contamination.
Having said that, the authors went on to evaluate the antibiotic resistance in the different systems. Free run barns were worst, then cage barns, then free range (outside), organic and backyard flocks had the least antibiotic resistance. Both these findings make sense to me. Large scale farms have a higher tendency to use antibiotics (thus the resistance), whereas backyard flocks almost never medicate (sometimes that is itself a problem).
Which is more important? I don’t know. Antibiotic resistance doesn’t necessarily mean that the bacteria is likely to make you sick…it just means that if you treat an infection, you are more likely to clear it. Some resistant bacteria don’t make you sick at all….some susceptible bacteria make you deathly ill, very quickly. On the other hand, if you DO get sick from a resistant bacteria, it can be a serious problem.
Bottom line, eggs from backyard flocks are more likely to be contaminated by bacteria than anything you would buy in a grocery store. Be careful with them….wash your hands; keep the eggs in the fridge, separate from other foods; rinse eggs in running water to remove contamination before packing them in the fridge……and then relax. Contamination rates are very low, and most bacteria are not pathogenic. Take reasonable precautions and then just enjoy the fruits of your labours. You are as likely to give yourself an ulcer from stressing about the bacteria as you are of getting food poisoning.
Mike the Chicken Vet