San Mateo, CA — A former employee of the Atria Park of San Mateo assisted living community was sentenced to 40 days in county jail after a 2022 incident in which toxic cleaning fluid left in a pitcher was mistaken for juice and served to residents, killing two of them, according to court records and local reports.
Alisia Rivera Mendoza, 36, of East Palo Alto, pleaded no contest in August 2025 to felony elder abuse. A San Mateo County judge imposed the jail term and ordered 350 hours of community service in November 2025. The case stemmed from a criminal filing in April 2023 that initially included involuntary manslaughter and elder abuse counts, prosecutors said at the time.
What happened in 2022
In August 2022, Mendoza left a pitcher containing cleaning solution unattended at the Atria facility, according to case summaries. Another worker, believing the liquid was juice, served it to three residents. Two residents — Maxwell and Peter Schroder, both 93 — died following the poisoning. A third resident was hospitalized.
Authorities described the episode as an accidental but deadly lapse involving hazardous chemicals in a care setting. The charges and subsequent plea centered on Mendoza’s role in leaving the fluid in a container typically used for beverages, according to court filings.
How the case proceeded
San Mateo County prosecutors brought charges in April 2023, citing the residents’ deaths and the alleged negligence. Mendoza later entered her no-contest plea to a felony elder abuse count in August 2025, a change from the original manslaughter charge. In November 2025, the court imposed a 40-day jail sentence and community service, concluding the criminal case, according to local reports.
Officials did not provide additional details about the sentencing hearing, and the exact date in November was not specified in public summaries.
Facility response and safety questions
The incident occurred at Atria Park of San Mateo, part of Atria Senior Living. Public reports tied the 2022 poisonings to the facility but did not outline specific enforcement actions or penalties against the operator. Available coverage has focused on the criminal case against Mendoza and the tragic outcomes for the residents.
The case has renewed attention on how assisted living communities handle and store hazardous cleaning agents and how staff are trained to keep chemicals securely separated from food and beverage service. While no new regulatory actions were detailed in public reports, the episode underscores the stakes for safety protocols in senior care settings.
Key timeline
- August 2022: Cleaning solution left in a pitcher is mistakenly served to three residents; two later die.
- April 2023: County prosecutors file charges including involuntary manslaughter and elder abuse.
- August 2025: Mendoza pleads no contest to felony elder abuse.
- November 2025: She is sentenced to 40 days in jail and 350 hours of community service.
The sentencing closes a case that drew widespread concern over basic safeguards inside assisted living communities and the catastrophic consequences when those safeguards fail.
