Globally, a substantial amount of food that could potentially be repurposed as feed for farm animals is discarded each year. Former food products—originally manufactured for human consumption in compliance with legal standards—are removed from the human food chain. When used as feed, these products do not pose a risk to animal health. As part of this master’s thesis, we conducted a comprehensive review of the available literature on former food products. In Slovenia, we collected and analyzed the feed composition of selected samples (number of samples in parentheses): savoury (6), sweet (6), and mixed (1) bakery products, as well as fruit (2) and vegetables (7). The parameters examined included fatty acid profiles and oxidation indicators (peroxide value and malondialdehyde concentration). The results show that savoury and sweet bakery products are rich sources of fats, nitrogen-free extract, and energy, indicating their potential—albeit with certain limitations—as feed for farm animals. Compared to published data, the analyzed bakery products contained, on average, similar levels of crude fat, crude ash, and nitrogen-free extract, slightly higher crude protein, and lower crude fiber. Average concentrations of Ca, Na, and Mg were comparable to literature values, whereas P and K were lower. Fruit and vegetable samples exhibited high moisture content, which accelerates spoilage; therefore, rapid utilization or processing is essential. In bakery products, fruits, and vegetables, the average proportion of linoleic acid (C18:2 n-6) and polyunsaturated fatty acids exceeded that of monounsaturated and saturated fatty acids. Evidence of fat oxidation, indicated by peroxide values, was found in some savoury and sweet bakery samples and in all fruit and vegetable samples. Malondialdehyde measurements confirmed secondary oxidation in apples and all vegetables. Collecting and converting these products into animal feed could reduce reliance on imported feed and associated transportation, thereby contributing to lower greenhouse gas emissions. However, rapid consumption or processing is necessary to enable their safe reintroduction into the feed chain.
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