Dear Dr. Blonz: I read your column pretty regularly here in the San Francisco East Bay, and had to deal with our recent power outage. I was able to have a friend take my frozen food to keep it cold, but forgot about the mayonnaise, sour cream, milk and cream-based salad dressings. My power was out for 36 hours, and these items were only moderately cold when it restarted. What is a safe period for these types of food to be unrefrigerated? — B., San Francisco, California
Dear B.: I went through that same outage. It was quite disconcerting to experience this planned outage, complicated by howling winds, the very real threat of fire, and the knowledge that at any moment you might get the call to evacuate. All this with no reliable cell service. We had purchased a couple of hefty backup batteries to provide power for the fridge, and a solar panel to recharge the batteries. We could only get updates via AM radio.
With all the angst, our situation paled in comparison with those who ended up in the path of the fires and lost it all. Many others have yet to get their power turned back on. I am hopeful that these events will be a stark reminder of the need to invest in all aspects of infrastructure associated with our health and well-being, and not to wait for a tragedy to remind us what we should have been doing all along.
Stepping down from the soapbox, let me address the substance of your question. My thoughts are that in such situations, it is always prudent to toss “marginal” foods or those suspected of having been improperly stored. This would especially be the case for the items you list, as they are typically consumed without additional heat treatment that might help destroy unsafe elements.
Food safety experts say that four hours without power is the mark after which perishables should be tossed. In your case, we are talking about foods that remained in the fridge, so they would remain somewhat cold, depending on your appliance’s ability to retain its temperature. That ability is affected by the age, size and quality of the appliance, as well as each food’s location in the fridge, and how each product had been handled prior to the outage — i.e., whether, and how often, it had been opened and kept at room temperature before being returned to the fridge.
Then, we have the questions of how often the door was opened during the outage; were bags of ice or cold-packs put in the fridge to help maintain the cold; were the containers surrounded by objects that might have helped retain the cold, etc.
Finally, there is the issue of who will be consuming those items, and the status of their immune system. This is not an exact science; I am attempting to describe a gamble with lots of variables. The omnipresent bottom line is that, where health is concerned, it is a smaller, wiser investment to toss and replace than roll the dice.
(Ed Blonz, Ph.D., is a nutrition scientist and an assistant clinical professor at the University of California, San Francisco. He is the author of the digital book “The Wellness Supermarket Buying Guide” (2012), which is also available as a free digital resource at blonz.com/guide.)
Send questions to: “On Nutrition,” Ed Blonz, c/o Andrews McMeel Syndication, 1130 Walnut St., Kansas City, MO, 64106. Send email inquiries to firstname.lastname@example.org. Due to the volume of mail, personal replies cannot be provided.