One-third of global food, about 1.3 billion tons/year, are lost or wasted. Anaerobic digestion (AD) offers a sustainable route for recovering energy from food waste through biogas production, but conventional systems are commonly operated under mesophilic or thermophilic conditions and therefore require heating. Psychrophilic (low temperature) digestion could reduce the energy demand of AD in colder climates, although slower hydrolysis and lower microbial activity remain important operational challenges. To overcome these, cost-effective feedstock pretreatment technologies and inoculum selection are potential approaches to improve process performance. Mild pretreatment, such as torrefaction, may improve substrate accessibility, while cold-adapted microbiomes may support more efficient conversion at lower temperatures. Anoxic marine sediments are of particular interest because they host diverse cold-adapted microbial communities capable of sustaining the conversion of organic matter to volatile fatty acids and subsequently methane under low-temperature conditions. This study evaluated biogas production from untreated food waste (UFW) and torrefied food waste at 175°C (TFW) under low-temperature conditions (15±1°C and 20±2°C) during long-term operation. A cold-adapted inoculum derived from anoxic Baltic Sea sediment (BSS) was compared with anaerobic digester sludge (ADS), representing a conventional engineered mesophilic inoculum. Long-term operation has been conducted in 850 mL BPC® Air fermentation bottles at an initial substrate-to-inoculum ratio of 3 and an initial pH of 7. The results obtained so far demonstrate that UFW consistently resulted in higher cumulative methane yields than TFW across both inocula and temperature conditions. Moreover, BSS showed a longer lag phase than ADS at both temperatures, but achieved higher biogas yields from day 16 onwards. At day 35, cumulative methane yields from UFW with BSS reached 130.55 and 129.56 mL CH₄/g VS at 15 °C and 20 °C, respectively. In comparison, ADS achieved 113.39 mL and 120.82 mL CH₄/g VS at 15 °C and 20 °C, respectively. The study is ongoing; however, the preliminary findings show that BSS outperformed ADS across both temperatures and food waste samples. This suggests that cold-adapted marine sediment microbiomes may support methane production from food waste at temperatures as low as 15 °C. From an implementation perspective, the findings highlight inoculum selection as a key factor in developing lower-energy biogas processes under moderate ambient temperature conditions.