The 29-year-old said the hair, believed to be part of the cow's hide, had come from a £3 packet of frozen mince bought at Iceland's Gosport store.
Ms Stock said Iceland had investigated and given her £30 in vouchers as an apology.
It's completely traumatised her now. She was in buckets of tears. She was enjoying it until she found that and burst out crying.
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Wednesday evening's forecast for the west of the region
Wednesday evening's forecast for the east of the region
French president Emmanuel Macron has reportedly agreed to allow the artwork to leave France for the first time in its 950-year history.