This Halacha is an excerpt from our Sefer
Leaving a gentile alone in one’s home and how it effects the Kashrus of one’s kitchen:
It is initially forbidden to allow a gentile to remain alone with one’s eating utensils/vessels due to worry that he may use the vessels to cook non-Kosher foods [either non-Kosher ingredients or meat with milk]. This applies even if one plans to not use the vessels again until after 24 hours. This applies whether one desires to leave a vessel in the house of a gentile, or desires to leave a gentile alone in his home.
Yotzei Venichnas: If one is coming in and out of the house constantly, then it is permitted to leave the gentile alone in one’s home even initially.
Leaving a gentile at home while food is cooking: One is to be stringent not to leave pots [of cooking food] with one’s gentile maid, if no Jews will remain at home. If, however, one is constantly coming in and out of the house, than one may do so, as stated above. If, however, the maid knows that one will be gone for quite some time, such as he will be leaving to go to Shul and the like, one should be stringent.
Coming up in Part 2!
It is forbidden to leave one’s eating utensils, cookware, or food that is in the midst of cooking, in the care of a gentile, unless one is entering and exiting the area constantly.
May one leave eating utensils alone with a non-religious Jew?
It is forbidden to leave a Jew who is known to desecrate Shabbos in public, alone in one’s home with one’s Kosher kitchen unless a Torah observant Jew is constantly coming in and out of the house.
 Michaber/Rama Y.D. 122:9; Mordechai Perek Ein Mamidim, quoted in Taz 122:8; Igros Moshe Y.D. 3:61
 Igros Moshe Y.D. 3:61
 Michaber ibid; Mordechai ibid
 Rama ibid; Shach 122:8; Taz 122:8
 Michaber Y.D. 122:9 regarding bringing to house of gentile; Rama ibid that the same applies to leaving a gentile in one’s home “And initially one is to be careful in all cases even regarding maids and slaves in ones home, that our vessels should not remain with them as they amy come to use them with not Kosher food”; Mordechai ibid likewise mentions both cases; See Igros Moshe Y.D. 3:61 who even regarding bedieved treats the latter case the same as the former
 Shach 122:9 that so is custom today being that one may even initially rely on Yotzei Venichnas; Rama 118:12 brought next
 Michaber 118:12; Tur in name of Rosh Kelal 19:18; Vetzaruch Iyun why the Poskim here make no mention of the discussion of Bedieved in 122:9; Perhaps one can say there is a difference between one’s maid working in one’s house [the case here], in which we are always lenient Bedieved, and a case where one sends his item to the gentile’s house [the case in 122]. Vetzaruch Iyun. See coming footnotes in Bedieved.
The reason: As she may cook non-Kosher food in it. [Shach 118:37]
 Rama ibid
 Shach 118:37 in conclusion of opinion of Rama in Tur and Rosh ibid
 See Michaber 119:7 that such a Jew is like a gentile for all matters and is hence Chashud for everything; See also Michaber Y.D. 2:5 and Admur Shechita 2:10; Regarding a Jew who keeps Shabbos but eats non-Kosher: See Michaber 119:3 that one who is Chashud to eat Treif is not Chashud to steal Treif; See Rama 1181 and Shach 118:16